ALBERT

Beschreibung: A programmable energy efficient readout chip for a multiparameter highly integrated implantable biosensor system M. Nawito, H. Richter, A. Stett, and J. N. Burghartz Adv. Radio Sci., 13, 103-108, doi:10.5194/ars-13-103-2015, 2015 In this work an Application Specific Integrated Circuit (ASIC) for an implantable electrochemical biosensor system is presented. The ASIC drives the measurement electrodes and performs amperometric measurements for determining the oxygen concentration, potentiometric measurements for evaluating the pH‐level as well as temperature measurements. The chip was fabricated and shows good result which conform to the Simulation data.

Beschreibung: Reflexionseigenschaften von Windenergieanlagen im Funkfeld von Funknavigations- und Radarsystemen S. Sandmann, S. Divanbeigi, and H. Garbe Adv. Radio Sci., 13, 9-18, doi:10.5194/ars-13-9-2015, 2015 Die hier behandelte Untersuchung befasst sich mit den Störungen des elektrischen Feldes einer Doppler Very High Frequency Omnidirectional Radio Range Navigationsanlage (DVOR) in der Gegenwart von Windenergieanlagen (WEA). Hierfür wird die Feldstärke auf 25 konzentrischen Kreisbahnen, sog. Orbit Flights verschiedener Höhen und mit verschiedenen Radien rund um die DVOR-Anlage numerisch simuliert. Insbesondere werden die Einflüsse diverser Parameter der WEA wie deren Anzahl, Position, Rotorwinkel, Turmhöhe und Rotordurchmesser auf die Feldverteilung herausgestellt, sowie die Anwendbarkeit der Simulationsmethode Physical Optics (PO) durch Vergleich der Simulationsergebnisse mit denen der Multi Level Fast Multipol Method (MLFMM) untersucht.

Beschreibung: Validation of the radiation pattern of the VHF MST radar MAARSY by scattering off a sounding rocket's payload T. Renkwitz, C. Schult, R. Latteck, and G. Stober Adv. Radio Sci., 13, 41-48, doi:10.5194/ars-13-41-2015, 2015 The Middle Atmosphere Alomar Radar System (MAARSY) is a monostatic radar with an active phased array antenna designed for studies of phenomena in the mesosphere and lower thermosphere. Its design, in particular the flexible beam forming and steering capability, makes it a powerful instrument to perform observations with high angular and temporal resolution. For the configuration and analysis of experiments carried out with the radar it is essential to have knowledge of the actual radiation pattern. Therefore, during the time since the radar was put into operation various active and passive experiments have been performed to gain knowledge of the radiation pattern. With these experiments the beam pointing accuracy, the beam width and phase distribution of the antenna array were investigated. Here, the use of a sounding rocket and its payload as a radar target is described which was launched in the proximity of the radar. The analysis of these observations allows the detailed investigation of the two-way radiation pattern for different antenna array sizes and beam pointing positions.

Beschreibung: Improving the range of UHF RFID transponders using solar energy harvesting under low light conditions A. Ascher, M. Lehner, M. Eberhardt, and E. Biebl Adv. Radio Sci., 13, 81-86, doi:10.5194/ars-13-81-2015, 2015 The sensitivity of passive UHF RFID transponders (Radio Frequency Identification) is the key issue, which determines the maximum read range of an UHF RFID system. During this work the ability of improving the sensitivity using solar energy harvesting, especially for low light conditions, is shown. To use the additional energy harvested from the examined silicon and organic solar cells, the passive RFID system is changed into a semi-active one. This needs no changes on the reader hardware itself, only the used RFIC (Radio Frequency Integrated Circuit) of the transponder has to possess an additional input pin for an external supply voltage. The silicon and organic cells are evaluated and compared to each other regarding their low light performance. The different cells are examined in a shielded box, which is protected from the environmental lighting. Additionally, a demonstrator is shown, which makes the measurement of the extended read range with respect to the lighting conditions possible. If the cells are completely darkened, the sensitivity gain is ascertained using high capacity super caps. Due to the measurements an enhancement in range up to 70 % could be guaranteed even under low light conditions.

Beschreibung: Spherical-multipole analysis of an arbitrarily directed complex-source beam diffracted by an acoustically soft or hard circular cone A. Reinhardt, H. Bruens, L. Klinkenbusch, M. Katsav, and E. Heyman Adv. Radio Sci., 13, 57-61, doi:10.5194/ars-13-57-2015, 2015 An arbitrarily directed complex-source beam (CSB) is diffracted by an acoustically soft or hard semi-infinite circular cone. The method can be used to probe any desired part of the cone inclduing its tip. The scattered field is isolated by subtracting the incident from the diffracted field and can be used to derive diffraction coefficients for improving asymptotic methods such as the GTD or the UTD.

Beschreibung: Efficient determination of the left-eigenvectors for the Method of Lines S. F. Helfert Adv. Radio Sci., 13, 19-29, doi:10.5194/ars-13-19-2015, 2015 To enforce the continuity of transverse electric and magnetic fields at boundaries, rectangular matrices containing the field distribution ('right eigenvectors') have to be inverted. This can be done with left eigenvectors. Here, it is shown how the latter ones can be determined with simple matrix products from previously determined right eigenvectors. For this purpose the relation between the transverse electric and magnetic fields known from Maxwell's equations is utilized.

Beschreibung: Potential of dynamic spectrum allocation in LTE macro networks H. Hoffmann, P. Ramachandra, I. Z. Kovács, L. Jorguseski, F. Gunnarsson, and T. Kürner Adv. Radio Sci., 13, 95-102, doi:10.5194/ars-13-95-2015, 2015 In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km 2 . The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells.

Beschreibung: An active UHF RFID localization system for fawn saving M. Eberhardt, M. Lehner, A. Ascher, M. Allwang, and E. M. Biebl Adv. Radio Sci., 13, 87-94, doi:10.5194/ars-13-87-2015, 2015 This paper presents a localization concept for fawn saving. Fawns can be saved during pasture mowing by marking them with an active UHF RFID transponder. The system consists of a mowing-machine mounted direction-of-arrival (DOA) system and a handheld DOA device. Only by estimating the DOA one can reliable localize the marked fawns. The whole RFID and DOA system is presented and communication concept is shown.

Beschreibung: Charge pump design in 130 nm SiGe BiCMOS technology for low-noise fractional-N PLLs M. Kucharski and F. Herzel Adv. Radio Sci., 13, 133-139, doi:10.5194/ars-13-133-2015, 2015 This paper presents a charge pump (CP) designed for a high linearity and a low noise to be used in a fractional-N phase-locked loop (PLL). An internal supply regulator with low intrinsic device noise is included in the design optimization. The high CP linearity is shown to reduce the level of in-band spurs in a fractional-N PLL tremendously.

Beschreibung: A test method for analysing disturbed ethernet data streams M. Kreitlow, F. Sabath, and H. Garbe Adv. Radio Sci., 13, 149-153, doi:10.5194/ars-13-149-2015, 2015 Ethernet connections can suffer from data corruption due to intentional electromagnetic interference. In this paper a software-based measuring method is presented, which allows a direct assessment of the effects on the link layer without an unwanted influence of software related effects on higher protocol layers. This gives a simple tool for a quantitative analysis of the disturbance of an Ethernet connection based on time domain data.

Beschreibung: Design investigation to improve voltage swing and bandwidth of the SiGe driver circuit for a silicon electro-optic ring modulator A. Fatemi, H. Gaul, U. Keil, and H. Klar Adv. Radio Sci., 13, 121-125, doi:10.5194/ars-13-121-2015, 2015 This paper reports on a new SiGe driver IC to address the low breakdown voltage level of modern BiCMOS transistors. An optical modulator driver IC in SiGe 250 nm technology with a supply voltage of 4.5 V is presented. This driver IC consists of pre- and main driver stages where a newly modified cascode topology and capacitance degeneration technique is employed to meet current application requirements; high voltage swing at high datarate.

Beschreibung: High-voltage circuits for power management on 65 nm CMOS S. Pashmineh and D. Killat Adv. Radio Sci., 13, 109-120, doi:10.5194/ars-13-109-2015, 2015 This paper presents two high-voltage circuits used in power management, a switching driver for buck converter with optimized on-resistance and a low dropout (LDO) voltage regulator with 2-stacked pMOS pass devices. The circuit design is based on stacked MOSFETs, thus the circuits are technology independent.

Beschreibung: Impedance spectra classification for determining the state of charge on a lithium iron phosphate cell using a support vector machine P. Jansen, D. Vergossen, D. Renner, W. John, and J. Götze Adv. Radio Sci., 13, 127-132, doi:10.5194/ars-13-127-2015, 2015 New method for determining the state of charge on lithium iron phosphate cells using frequency domain data.

Beschreibung: Comparison of electromagnetic solvers for antennas mounted on vehicles M. S. L. Mocker, S. Hipp, F. Spinnler, H. Tazi, and T. F. Eibert Adv. Radio Sci., 13, 49-55, doi:10.5194/ars-13-49-2015, 2015 An electromagnetic solver comparison for various use cases of antennas mounted on vehicles is presented. For this purpose, several modeling approaches, called transient, frequency and integral solver, including the features fast resonant method and autoregressive filter, offered by CST MWS, are investigated. The solvers and methods are compared for a roof antenna itself, a simplified vehicle, a roof including a panorama window and a combination of antenna and vehicle. With these examples, the influence of different materials, data formats and parameters such as size and complexity are investigated. Also, the necessary configurations for the mesh and the solvers are described.

Beschreibung: Ein Konzept für den energieeffizienten Betrieb von Mobilfunknetzen N. Bayer and D. von Hugo Adv. Radio Sci., 13, 63-72, doi:10.5194/ars-13-63-2015, 2015 Maßnahmen zur Senkung des Energieverbrauches im Mobilfunk wurden im Forschungsförderungsprojekt ComGreen untersucht. Ein an die tatsächliche Auslastung angepasster Betrieb des Funkzugangsnetzes, der durch intelligente dynamische Rekonfiguration unter Nutzung von Kontextinformation erreicht werden kann, ermöglicht Energieeinsparungen im Bereich von 25–40 %. Dies wird durch Ergebnisse von Computer-Simulationen und anhand von Messungen, die an einer Testinstallation durchgeführt wurden, belegt.

Beschreibung: Is model-order reduction viable for the broadband finite-element analysis of electrically large antenna arrays? O. Floch, A. Sommer, O. Farle, and R. Dyczij-Edlinger Adv. Radio Sci., 13, 31-39, doi:10.5194/ars-13-31-2015, 2015 Model-order reduction provides an efficient way of computing frequency sweeps for finite-element models, because the dimension of the reduced-order system depends on the complexity of the frequency response rather than the size of the original model. For electrically large domains, however, the applicability of such methods is unclear because the system response may be very complicated. This paper provides a numerical study of the effects of bandwidth, electrical size, and scan angle on the size and convergence of the ROM, by considering linear antenna arrays. A mathematical model is proposed and validated against numerical experiments.

Beschreibung: Definition and test of the electromagnetic immunity of UAS for first responders C. Adami, S. Chmel, M. Jöster, T. Pusch, and M. Suhrke Adv. Radio Sci., 13, 141-147, doi:10.5194/ars-13-141-2015, 2015 Recent technological developments considerably lowered the barrier for unmanned aerial systems (UAS) to be employed in a variety of usage scenarios, comprising live video transmission from otherwise inaccessible vantage points. As an example, in the French-German ANCHORS project several UAS guided by swarm intelligence provide aerial views and environmental data of a disaster site while deploying an ad-hoc communication network for first responders. Since being able to operate in harsh environmental conditions is a key feature, the immunity of the UAS against radio frequency (RF) exposure has been studied. Conventional Electromagnetic Compatibility (EMC) applied to commercial and industrial electronics is not sufficient since UAS are airborne and can as such move beyond the bounds within which RF exposure is usually limited by regulatory measures. Therefore, the EMC requirements have been complemented by a set of specific RF test frequencies and parameters where strong sources are expected to interfere in the example project test case of an inland port environment. While no essential malfunctions could be observed up to field strengths of 30 V m −1 , a sophisticated, more exhaustive approach for testing against potential sources of interference in key scenarios of UAS usage should be derived from our present findings.

Beschreibung: 〈b〉Radar target simulator with complex-valued delay line modeling based on standard radar components〈/b〉〈br〉 Andreas R. Diewald, Manuel Steins, and Simon Müller〈br〉 Adv. Radio Sci., 16, 203-213, https://doi.org/10.5194/ars-16-203-2018, 2018〈br〉 A concept of low-cost hardware for radar target simulation is presented. The theoretical foundations are derived and analyzed. An implementation of a demonstrator operating in the 24 GHz ISM band is shown for which the dynamical range simulation was implemented in a FPGA with fast sampling 10 ADCs and DACs. By using a FIR filtering approach a fine discretization of the range could be reached which will furthermore allow an inherent and automatic Doppler simulation by moving the target.

Beschreibung: 〈b〉Spectrum management and compatibility studies with Python〈/b〉〈br〉 Benjamin Winkel and Axel Jessner〈br〉 Adv. Radio Sci., 16, 177-194, https://doi.org/10.5194/ars-16-177-2018, 2018〈br〉 We developed the software "pycraf". It allows to analyse the compatibility between applications and services that make use of radio waves, for example mobile communications providers. The radio wave spectrum is very limited, which makes it important that devices do not interfere with each other. One major application of "pycraf" is to calculate protection criteria for radio astronomy observatories, which are extremely sensitive to man-made radio emission, potentially rendering them blind.

Beschreibung: 〈b〉Propagation of current waves along a transmission line with randomly located non-uniformities inside a rectangular resonator〈/b〉〈br〉 Sergey V. Tkachenko, Jürgen B. Nitsch, Moustafa Raya, Ronald Rambousky, and Ralf Vick〈br〉 Adv. Radio Sci., 16, 195-201, https://doi.org/10.5194/ars-16-195-2018, 2018〈br〉 In this paper, we investigate the propagation of high-frequency current waves along a stochastic transmission line inside a rectangular cavity using as basis the model of a transmission line with the symmetry of the resonator. The stochastization of the line is created by a stochastically arranged chain of loads. Using similar models one also can take into account stochastic geometry of the line.

Beschreibung: Challenges for Wireless Mesh Networks to provide reliable carrier-grade services Advances in Radio Science, 9, 377-382, 2011 Author(s): D. von Hugo and N. Bayer Provision of mobile and wireless services today within a competitive environment and driven by a huge amount of steadily emerging new services and applications is both challenge and chance for radio network operators. Deployment and operation of an infrastructure for mobile and wireless broadband connectivity generally requires planning effort and large investments. A promising approach to reduce expenses for radio access networking is offered by Wireless Mesh Networks (WMNs). Here traditional dedicated backhaul connections to each access point are replaced by wireless multi-hop links between neighbouring access nodes and few gateways to the backbone employing standard radio technology. Such a solution provides at the same time high flexibility in both deployment and the amount of offered capacity and shall reduce overall expenses. On the other hand currently available mesh solutions do not provide carrier grade service quality and reliability and often fail to cope with high traffic load. EU project CARMEN (CARrier grade MEsh Networks) was initiated to incorporate different heterogeneous technologies and new protocols to allow for reliable transmission over "best effort" radio channels, to support a reliable mobility and network management, self-configuration and dynamic resource usage, and thus to offer a permanent or temporary broadband access at high cost efficiency. The contribution provides an overview on preliminary project results with focus on main technical challenges from a research and implementation point of view. Especially impact of mesh topology on the overall system performance in terms of throughput and connection reliability and aspects of a dedicated hybrid mobility management solution will be discussed.

Beschreibung: Meteor radar measurements of mean winds and tides over Collm (51.3° N, 13° E) and comparison with LF drift measurements 2005–2007 Advances in Radio Science, 9, 335-341, 2011 Author(s): C. Jacobi An all-sky VHF meteor radar (MR) has been continuously operated at Collm (51.3° N, 13° E) since summer 2004. The radar measures meteor parameters, diffusion coefficients, and horizontal winds in the mesopause region. There exists a temporal overlap of the MR wind measurements with co-located low-frequency (LF) ionospheric drift measurements until 2007. Comparison of MR and LF semidiurnal tidal phases allows to empirically determine the virtual height overestimation of LF reflection heights due to the group retardation of LF waves. LF reference heights have to be reduced by up to 20 km to match real heights. Correction of LF heights for group retardation allows to determine the wind underestimation by the LF method compared with meteor radar measurements and opens the possibility to continue long-term trend analysis using mesosphere/lower thermosphere winds.

Beschreibung: IP-based mobility management for heterogeneous wireless access Advances in Radio Science, 10, 319-325, 2012 Author(s): H. J. Einsiedler and D. von Hugo Future high quality communication services will be offered in an integrated or converged network infrastructure maintaining both fixed wireless and mobile access via multi-mode user terminals. A support of various scenarios of user and/or terminal mobility within a common IP-based infrastructure requires intelligently designed control protocols. A major challenge is to provide seamless (i.e. lossless and low delay) handover between different radio cells and operator domains to enable continuation of unicast and multicast sessions while using network resources most efficiently. IETF (Internet Engineering Task Force) is specifying related IP mobility management protocols to be applicable also to a flat architecture as envisaged by Next Generation (Mobile) Networks (NGNs/NGMNs). The contribution will describe operator requirements towards such an approach. Both single-domain and multi-domain scenarios will be discussed based on federation ideas. Already existing solutions are taken into consideration and application of solution proposals towards a Distributed Mobility Management (DMM) currently under evaluation within IETF will be outlined.

Beschreibung: STF Optimierung von single-bit CT ΣΔ Modulatoren basierend auf skalierten Filterkoeffizienten Advances in Radio Science, 10, 313-317, 2012 Author(s): C. Widemann, C. Zorn, T. Brückner, M. Ortmanns, and W. Mathis Die vorliegende Arbeit beschäftigt sich mit dem Signalübertragungsverhalten von single-bit continuous-time (CT) ΣΔ Modulatoren. Dabei liegt der Fokus der Untersuchung auf dem Peaking der Signaltransferfunktion (STF). Dieser Effekt kann die Performance und die Stabilität des Gesamtsystems negativ beeinflussen, da bei auftretendem STF-Peaking Signale außerhalb des Signalbands verstärkt werden. In dieser Arbeit wird ein neuer Ansatz zur Reduktion des Peakings vorgestellt, der auf der Optimierung der Systemdynamik basiert. Dabei werden die Filterkoeffizienten des Modulators systematisch angepasst. Anhand eines Beispielsystems wird gezeigt, dass der Ansatz genutzt werden kann, um das Übertragungsverhalten des Modulators abhängig vom Ausgangssystem zu verändern. So kann entweder die Systemsperformance verbessert werden, ohne Peaking in der STF zu erzeugen, oder das STF-Peaking reduziert werden, ohne die Systemperformance stark zu beeinflussen.

Beschreibung: Differential Algebraic Equations of MOS Circuits and Jump Behavior Advances in Radio Science, 10, 327-332, 2012 Author(s): P. Sarangapani, T. Thiessen, and W. Mathis Many nonlinear electronic circuits showing fast switching behavior exhibit jump effects which occurs when the state space of the electronic system contains a fold. This leads to difficulties during the simulation of these systems with standard circuit simulators. A method to overcome these problems is by regularization, where parasitic inductors and capacitors are added at the suitable locations. However, the transient solution will not be reliable if this regularization is not done in accordance with Tikhonov's Theorem. A geometric approach is taken to overcome these problems by explicitly computing the state space and jump points of the circuit. Until now, work has been done in analyzing example circuits exhibiting this behavior for BJT transistors. In this work we apply these methods to MOS circuits (Schmitt trigger, flip flop and multivibrator) and present the numerical results. To analyze the circuits we use the EKV drain current model as equivalent circuit model for the MOS transistors.

Beschreibung: Is model-order reduction viable for the broadband finite-element analysis of electrically large antenna arrays? O. Floch, A. Sommer, O. Farle, and R. Dyczij-Edlinger Adv. Radio Sci., 13, 31-39, doi:10.5194/ars-13-31-2015, 2015 Model-order reduction provides an efficient way of computing frequency sweeps for finite-element models, because the dimension of the reduced-order system depends on the complexity of the frequency response rather than the size of the original model. For electrically large domains, however, the applicability of such methods is unclear because the system response may be very complicated. This paper provides a numerical study of the effects of bandwidth, electrical size, and scan angle on the size and convergence of the ROM, by considering linear antenna arrays. A mathematical model is proposed and validated against numerical experiments.

Beschreibung: Ein Konzept für den energieeffizienten Betrieb von Mobilfunknetzen N. Bayer and D. von Hugo Adv. Radio Sci., 13, 63-72, doi:10.5194/ars-13-63-2015, 2015 Maßnahmen zur Senkung des Energieverbrauches im Mobilfunk wurden im Forschungsförderungsprojekt ComGreen untersucht. Ein an die tatsächliche Auslastung angepasster Betrieb des Funkzugangsnetzes, der durch intelligente dynamische Rekonfiguration unter Nutzung von Kontextinformation erreicht werden kann, ermöglicht Energieeinsparungen im Bereich von 25–40 %. Dies wird durch Ergebnisse von Computer-Simulationen und anhand von Messungen, die an einer Testinstallation durchgeführt wurden, belegt.

Beschreibung: Improving the range of UHF RFID transponders using solar energy harvesting under low light conditions A. Ascher, M. Lehner, M. Eberhardt, and E. Biebl Adv. Radio Sci., 13, 81-86, doi:10.5194/ars-13-81-2015, 2015 The sensitivity of passive UHF RFID transponders (Radio Frequency Identification) is the key issue, which determines the maximum read range of an UHF RFID system. During this work the ability of improving the sensitivity using solar energy harvesting, especially for low light conditions, is shown. To use the additional energy harvested from the examined silicon and organic solar cells, the passive RFID system is changed into a semi-active one. This needs no changes on the reader hardware itself, only the used RFIC (Radio Frequency Integrated Circuit) of the transponder has to possess an additional input pin for an external supply voltage. The silicon and organic cells are evaluated and compared to each other regarding their low light performance. The different cells are examined in a shielded box, which is protected from the environmental lighting. Additionally, a demonstrator is shown, which makes the measurement of the extended read range with respect to the lighting conditions possible. If the cells are completely darkened, the sensitivity gain is ascertained using high capacity super caps. Due to the measurements an enhancement in range up to 70 % could be guaranteed even under low light conditions.

Beschreibung: Spherical-multipole analysis of an arbitrarily directed complex-source beam diffracted by an acoustically soft or hard circular cone A. Reinhardt, H. Bruens, L. Klinkenbusch, M. Katsav, and E. Heyman Adv. Radio Sci., 13, 57-61, doi:10.5194/ars-13-57-2015, 2015 An arbitrarily directed complex-source beam (CSB) is diffracted by an acoustically soft or hard semi-infinite circular cone. The method can be used to probe any desired part of the cone inclduing its tip. The scattered field is isolated by subtracting the incident from the diffracted field and can be used to derive diffraction coefficients for improving asymptotic methods such as the GTD or the UTD.

Beschreibung: Potential of dynamic spectrum allocation in LTE macro networks H. Hoffmann, P. Ramachandra, I. Z. Kovács, L. Jorguseski, F. Gunnarsson, and T. Kürner Adv. Radio Sci., 13, 95-102, doi:10.5194/ars-13-95-2015, 2015 In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km 2 . The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells.

Beschreibung: Charge pump design in 130 nm SiGe BiCMOS technology for low-noise fractional-N PLLs M. Kucharski and F. Herzel Adv. Radio Sci., 13, 133-139, doi:10.5194/ars-13-133-2015, 2015 This paper presents a charge pump (CP) designed for a high linearity and a low noise to be used in a fractional-N phase-locked loop (PLL). An internal supply regulator with low intrinsic device noise is included in the design optimization. The high CP linearity is shown to reduce the level of in-band spurs in a fractional-N PLL tremendously.

Beschreibung: Definition and test of the electromagnetic immunity of UAS for first responders C. Adami, S. Chmel, M. Jöster, T. Pusch, and M. Suhrke Adv. Radio Sci., 13, 141-147, doi:10.5194/ars-13-141-2015, 2015 Recent technological developments considerably lowered the barrier for unmanned aerial systems (UAS) to be employed in a variety of usage scenarios, comprising live video transmission from otherwise inaccessible vantage points. As an example, in the French-German ANCHORS project several UAS guided by swarm intelligence provide aerial views and environmental data of a disaster site while deploying an ad-hoc communication network for first responders. Since being able to operate in harsh environmental conditions is a key feature, the immunity of the UAS against radio frequency (RF) exposure has been studied. Conventional Electromagnetic Compatibility (EMC) applied to commercial and industrial electronics is not sufficient since UAS are airborne and can as such move beyond the bounds within which RF exposure is usually limited by regulatory measures. Therefore, the EMC requirements have been complemented by a set of specific RF test frequencies and parameters where strong sources are expected to interfere in the example project test case of an inland port environment. While no essential malfunctions could be observed up to field strengths of 30 V m −1 , a sophisticated, more exhaustive approach for testing against potential sources of interference in key scenarios of UAS usage should be derived from our present findings.

Beschreibung: A test method for analysing disturbed ethernet data streams M. Kreitlow, F. Sabath, and H. Garbe Adv. Radio Sci., 13, 149-153, doi:10.5194/ars-13-149-2015, 2015 Ethernet connections can suffer from data corruption due to intentional electromagnetic interference. In this paper a software-based measuring method is presented, which allows a direct assessment of the effects on the link layer without an unwanted influence of software related effects on higher protocol layers. This gives a simple tool for a quantitative analysis of the disturbance of an Ethernet connection based on time domain data.

Beschreibung: Analysis of the effect of different absorber materials and loading on the shielding effectiveness of a metallic enclosure S. Parr, H. Karcoon, S. Dickmann, and R. Rambousky Adv. Radio Sci., 13, 155-159, doi:10.5194/ars-13-155-2015, 2015 Absorbers used for improving the Shielding Effectiveness (SE) are compared in their electromagnetic performance. Therefore the permittivity and permeability are determined with a coaxial line experiment. The effect of loading in the form of metallic and dielectric structures inside a metallic enclosure on the SE is analyzed. It turns out, that the SE can be improved by using absorber. Also, the SE is affected by loading inside the metallic enclosure.

Beschreibung: A novel ZePoC encoder for sinusoidal signals with a predictable accuracy for an AC power standard T. Vennemann, T. Frye, Z. Liu, M. Kahmann, and W. Mathis Adv. Radio Sci., 13, 1-8, doi:10.5194/ars-13-1-2015, 2015 In this paper we present an analytical formulation of a Zero Position Coding (ZePoC) encoder for an AC power standard based on class-D topologies. For controlling a class-D power stage a binary signal with special spectral characteristics will be generated by this ZePoC encoder for sinusoidal signals. These spectral characteristics have a predictable accuracy within a separated baseband to keep the noise floor below a specified level. Simulation results will validate the accuracy of this novel ZePoC encoder. For a real-time implementation of the encoder on a DSP/FPGA hardware architecture a trade-off between accuracy and speed of the ZePoC algorithm has to be made. Therefore the numerical effects of different floating point formats will be analyzed.

Beschreibung: Reflexionseigenschaften von Windenergieanlagen im Funkfeld von Funknavigations- und Radarsystemen S. Sandmann, S. Divanbeigi, and H. Garbe Adv. Radio Sci., 13, 9-18, doi:10.5194/ars-13-9-2015, 2015 Die hier behandelte Untersuchung befasst sich mit den Störungen des elektrischen Feldes einer Doppler Very High Frequency Omnidirectional Radio Range Navigationsanlage (DVOR) in der Gegenwart von Windenergieanlagen (WEA). Hierfür wird die Feldstärke auf 25 konzentrischen Kreisbahnen, sog. Orbit Flights verschiedener Höhen und mit verschiedenen Radien rund um die DVOR-Anlage numerisch simuliert. Insbesondere werden die Einflüsse diverser Parameter der WEA wie deren Anzahl, Position, Rotorwinkel, Turmhöhe und Rotordurchmesser auf die Feldverteilung herausgestellt, sowie die Anwendbarkeit der Simulationsmethode Physical Optics (PO) durch Vergleich der Simulationsergebnisse mit denen der Multi Level Fast Multipol Method (MLFMM) untersucht.

Beschreibung: Efficient determination of the left-eigenvectors for the Method of Lines S. F. Helfert Adv. Radio Sci., 13, 19-29, doi:10.5194/ars-13-19-2015, 2015 To enforce the continuity of transverse electric and magnetic fields at boundaries, rectangular matrices containing the field distribution ('right eigenvectors') have to be inverted. This can be done with left eigenvectors. Here, it is shown how the latter ones can be determined with simple matrix products from previously determined right eigenvectors. For this purpose the relation between the transverse electric and magnetic fields known from Maxwell's equations is utilized.

Beschreibung: A programmable energy efficient readout chip for a multiparameter highly integrated implantable biosensor system M. Nawito, H. Richter, A. Stett, and J. N. Burghartz Adv. Radio Sci., 13, 103-108, doi:10.5194/ars-13-103-2015, 2015 In this work an Application Specific Integrated Circuit (ASIC) for an implantable electrochemical biosensor system is presented. The ASIC drives the measurement electrodes and performs amperometric measurements for determining the oxygen concentration, potentiometric measurements for evaluating the pH‐level as well as temperature measurements. The chip was fabricated and shows good result which conform to the Simulation data.

Beschreibung: High-voltage circuits for power management on 65 nm CMOS S. Pashmineh and D. Killat Adv. Radio Sci., 13, 109-120, doi:10.5194/ars-13-109-2015, 2015 This paper presents two high-voltage circuits used in power management, a switching driver for buck converter with optimized on-resistance and a low dropout (LDO) voltage regulator with 2-stacked pMOS pass devices. The circuit design is based on stacked MOSFETs, thus the circuits are technology independent.

Beschreibung: Design investigation to improve voltage swing and bandwidth of the SiGe driver circuit for a silicon electro-optic ring modulator A. Fatemi, H. Gaul, U. Keil, and H. Klar Adv. Radio Sci., 13, 121-125, doi:10.5194/ars-13-121-2015, 2015 This paper reports on a new SiGe driver IC to address the low breakdown voltage level of modern BiCMOS transistors. An optical modulator driver IC in SiGe 250 nm technology with a supply voltage of 4.5 V is presented. This driver IC consists of pre- and main driver stages where a newly modified cascode topology and capacitance degeneration technique is employed to meet current application requirements; high voltage swing at high datarate.

Beschreibung: Impedance spectra classification for determining the state of charge on a lithium iron phosphate cell using a support vector machine P. Jansen, D. Vergossen, D. Renner, W. John, and J. Götze Adv. Radio Sci., 13, 127-132, doi:10.5194/ars-13-127-2015, 2015 New method for determining the state of charge on lithium iron phosphate cells using frequency domain data.

Beschreibung: Comparison of electromagnetic solvers for antennas mounted on vehicles M. S. L. Mocker, S. Hipp, F. Spinnler, H. Tazi, and T. F. Eibert Adv. Radio Sci., 13, 49-55, doi:10.5194/ars-13-49-2015, 2015 An electromagnetic solver comparison for various use cases of antennas mounted on vehicles is presented. For this purpose, several modeling approaches, called transient, frequency and integral solver, including the features fast resonant method and autoregressive filter, offered by CST MWS, are investigated. The solvers and methods are compared for a roof antenna itself, a simplified vehicle, a roof including a panorama window and a combination of antenna and vehicle. With these examples, the influence of different materials, data formats and parameters such as size and complexity are investigated. Also, the necessary configurations for the mesh and the solvers are described.

Beschreibung: Validation of the radiation pattern of the VHF MST radar MAARSY by scattering off a sounding rocket's payload T. Renkwitz, C. Schult, R. Latteck, and G. Stober Adv. Radio Sci., 13, 41-48, doi:10.5194/ars-13-41-2015, 2015 The Middle Atmosphere Alomar Radar System (MAARSY) is a monostatic radar with an active phased array antenna designed for studies of phenomena in the mesosphere and lower thermosphere. Its design, in particular the flexible beam forming and steering capability, makes it a powerful instrument to perform observations with high angular and temporal resolution. For the configuration and analysis of experiments carried out with the radar it is essential to have knowledge of the actual radiation pattern. Therefore, during the time since the radar was put into operation various active and passive experiments have been performed to gain knowledge of the radiation pattern. With these experiments the beam pointing accuracy, the beam width and phase distribution of the antenna array were investigated. Here, the use of a sounding rocket and its payload as a radar target is described which was launched in the proximity of the radar. The analysis of these observations allows the detailed investigation of the two-way radiation pattern for different antenna array sizes and beam pointing positions.

Beschreibung: An active UHF RFID localization system for fawn saving M. Eberhardt, M. Lehner, A. Ascher, M. Allwang, and E. M. Biebl Adv. Radio Sci., 13, 87-94, doi:10.5194/ars-13-87-2015, 2015 This paper presents a localization concept for fawn saving. Fawns can be saved during pasture mowing by marking them with an active UHF RFID transponder. The system consists of a mowing-machine mounted direction-of-arrival (DOA) system and a handheld DOA device. Only by estimating the DOA one can reliable localize the marked fawns. The whole RFID and DOA system is presented and communication concept is shown.

Beschreibung: A high throughput architecture for a low complexity soft-output demapping algorithm I. Ali, U. Wasenmüller, and N. Wehn Adv. Radio Sci., 13, 73-80, doi:10.5194/ars-13-73-2015, 2015 Iterative channel decoders such as Turbo-Code and LDPC decoders show exceptional performance and therefore they are a part of many wireless communication receivers nowadays. These decoders require a soft input, i.e., the logarithmic likelihood ratio (LLR) of the received bits with a typical quantization of 4 to 6 bits. For computing the LLR values from a received complex symbol, a soft demapper is employed in the receiver. The implementation cost of traditional soft-output demapping methods is relatively large in high order modulation systems, and therefore low complexity demapping algorithms are indispensable in low power receivers. In the presence of multiple wireless communication standards where each standard defines multiple modulation schemes, there is a need to have an efficient demapper architecture covering all the flexibility requirements of these standards. Another challenge associated with hardware implementation of the demapper is to achieve a very high throughput in double iterative systems, for instance, MIMO and Code-Aided Synchronization. In this paper, we present a comprehensive communication and hardware performance evaluation of low complexity soft-output demapping algorithms to select the best algorithm for implementation. The main goal of this work is to design a high throughput, flexible, and area efficient architecture. We describe architectures to execute the investigated algorithms. We implement these architectures on a FPGA device to evaluate their hardware performance. The work has resulted in a hardware architecture based on the figured out best low complexity algorithm delivering a high throughput of 166 Msymbols/second for Gray mapped 16-QAM modulation on Virtex-5. This efficient architecture occupies only 127 slice registers, 248 slice LUTs and 2 DSP48Es.

Beschreibung: Local Dynamic Map als modulares Software Framework für Fahrerassistenzsysteme Advances in Radio Science, 13, 203-207, 2015 Author(s): P. Reisdorf, A. Auerswald, and G. Wanielik Moderne Fahrerassistenzsysteme basieren auf der Verarbeitung von Informationen, welche durch die Umfeldwahrnehmung mit unterschiedlicher Sensorik erfolgt. Neben den Informationen aus dem eigenen Fahrzeug ergeben sich durch unterschiedliche Kommunikationsmöglichkeiten (Car2Car, Car2X,...) erweiterte Umfeldwahrnehmungen (siehe Abb. 1). Diese Daten gilt es aufbereitet und zielorientiert einer Anwendung zur Verfügung zu stellen, was mit Hilfe einer Local Dynamic Map (LDM) erfüllt werden kann. Die vorliegende Veröffentlichung beschreibt den Aufbau, Verwendungszweck und Eigenschaften einer entwickelten LDM und geht auf einige Applikationen ein, die mit Hilfe dieser realisiert wurden.

Beschreibung: Understanding and optimizing microstrip patch antenna cross polarization radiation on element level for demanding phased array antennas in weather radar applications Advances in Radio Science, 13, 251-268, 2015 Author(s): D. Vollbracht The antenna cross polarization suppression (CPS) is of significant importance for the accurate calculation of polarimetric weather radar moments. State-of-the-art reflector antennas fulfill these requirements, but phased array antennas are changing their CPS during the main beam shift, off-broadside direction. Since the cross polarization (x-pol) of the array pattern is affected by the x-pol element factor, the single antenna element should be designed for maximum CPS, not only at broadside, but also for the complete angular electronic scan (e-scan) range of the phased array antenna main beam positions. Different methods for reducing the x-pol radiation from microstrip patch antenna elements, available from literature sources, are discussed and summarized. The potential x-pol sources from probe fed microstrip patch antennas are investigated. Due to the lack of literature references, circular and square shaped X-Band radiators are compared in their x-pol performance and the microstrip patch antenna size variation was analyzed for improved x-pol pattern. Furthermore, the most promising technique for the reduction of x-pol radiation, namely "differential feeding with two RF signals 180° out of phase", is compared to single fed patch antennas and thoroughly investigated for phased array applications with simulation results from CST MICROWAVE STUDIO (CST MWS). A new explanation for the excellent port isolation of dual linear polarized and differential fed patch antennas is given graphically. The antenna radiation pattern from single fed and differential fed microstrip patch antennas are analyzed and the shapes of the x-pol patterns are discussed with the well-known cavity model. Moreover, two new visual based electromagnetic approaches for the explanation of the x-pol generation will be given: the field line approach and the surface current distribution approach provide new insight in understanding the generation of x-pol component in microstrip patch antenna radiation patterns.

Beschreibung: Networks of high frequency inhomogeneous transmission lines Advances in Radio Science, 13, 189-195, 2015 Author(s): F. Ossevorth, H. G. Krauthäuser, S. Tkachenko, J. Nitsch, and R. Rambousky It is well known from classical transmission line theory, that transmission lines can be folded into impedances and thereby used in an electrical network setting. But it is also possible to create large networks of transmission lines consisting of tubes and junctions. The tubes contain the transmission lines and the junctions consider the mutual influences of the adjacent tubes or the terminals. The calculation of the currents and voltages at the junctions can be performed with the help the BLT-equation. So far this method is not applicable for nonuniform transmission lines described in a full wave method, because the lack of a distinct voltage gives no possibility for junctions. Junctions only make sense, when the considered network offers the possibility to propagate a TEM-Mode. If this requirement is fullfilled, nonuniform transmission lines could be included in an electrical network. This approach is validated in this paper in form of numerical simulations as well as measurements.

Beschreibung: 3-D transponder antennas for future SHF RFID applications Advances in Radio Science, 9, 401-405, 2011 Author(s): R. Zichner and R. R. Baumann The radio frequency identification (RFID) technology is omnipresent since a few years. Some of the most popular fields of application are the use for security tasks, for logistics and for the consumer segment. For example, chip card or key ring sized RFID transponders can allow wireless access to secured rooms. The number of applications for wireless data transmission for the identification and tracking of objects increases every year. There is a large development need for highly functional and inexpensive RFID transponders due to the ever-increasing demand on improved reliability, higher data rates and read and write ranges of the RFID systems. Therefore, research was performed on new 3-D transponder antennas for the Super High Frequency Band around 5.8 GHz. Additionally, wave propagation effects and the influence of different dielectric environments were considered. Parallel to the design of the novel antenna structures, the printing process for inexpensive manufacturing was investigated. The gained results are the basis for prospective RFID applications.

Beschreibung: Traditional protection ratios in FM sound broadcasting – still appropriate for interference management? Advances in Radio Science, 9, 391-396, 2011 Author(s): J. Philipp A detailed analysis of the measurement procedures recommended by the International Telecommunication Union (ITU) shows that – with proper definition of audio quality – the FM broadcasting system can provide an audio signal-to-noise ratio of no better than 40 dB, when the interference in the neighboring channels exhausts the limits established by the internationally agreed protection ratios. Thus any attempt to relax the protection, be it motivated by the desire to implement additional FM or new digital services in the FM band, would inevitably degrade reception quality of existing services to levels hardly acceptable by broadcast listeners.

Beschreibung: Equitable access to spectrum in further development of the Geneva 2006 frequency plan Advances in Radio Science, 9, 397-400, 2011 Author(s): J. Philipp Since the frequency plan of the Regional Radiocommunication Conference Geneva 2006 has come into force, many attempts have been made towards its enhancement. The preliminary results, however, seem not to be compliant with elementary principles of distribution justice. Therefore, the planning principles which lead to the observed imbalance will be scrutinized. Furthermore it will be shown that the utilization of spectrum can be advanced in a balanced way when the same (necessary) condition for "equitable access", which has been used by a group of middle European countries for the construction of the original frequency plan, is applied to plan refinements as well. The necessary condition mentioned consists simply in the parity of the number of coverages (constituted of disjoint allotments) configured in the plan for each country. In order to be able to plan enhancements, the concept of coverage number has to be generalized to the case of incomplete coverages of potentially overlapping allotments. The computation of coverage numbers is straightforward and renders the concept of coverage number parity a useful tool to be applied as a necessary condition in testing a frequency plan variant for equitable access.

Beschreibung: Some anomalies of mesosphere/lower thermosphere parameters during the recent solar minimum Advances in Radio Science, 9, 343-348, 2011 Author(s): Ch. Jacobi, P. Hoffmann, M. Placke, and G. Stober The recent solar minimum has been characterized by an anomalous strong decrease of thermospheric density since 2005. Here we analyze anomalies of mesosphere/lower thermosphere parameters possibly connected with this effect. In particular, nighttime mean LF reflection heights measured at Collm, Germany, show a very strong decrease after 2005, indicating a density decrease. This decrease is also visible in mean meteor heights measured with VHF meteor radar at Collm. This density decrease is accompanied by an increase of gravity wave (GW) amplitudes in the upper mesosphere and a decrease in the lower thermosphere. On the decadal scale, GWs are negatively correlated with the background zonal wind, but this correlation is modulated in the course of the solar cycle, indicating the combined effect of GW filtering and density decrease.

Beschreibung: Reduction of heat sink common-mode currents in switching mode power supply circuits Advances in Radio Science, 9, 317-321, 2011 Author(s): J. Kulanayagam, J. H. Hagmann, K. F. Hoffmann, and S. Dickmann In this paper, a new filter design for a heat sink is presented. The parasitic couplings between electric power devices and the heat sink are responsible for common-mode currents. The main focus is on the reduction of these currents to reduce the heat sink radiation. For this purpose a new filter design is proposed. In addition, experimental results are shown to validate the proposed filter.

Beschreibung: Betrachtungen zur Frequenzplanung für terrestrisches Fernsehen in den 50er Jahren in Mitteleuropa Advances in Radio Science, 9, 359-371, 2011 Author(s): U. Kühn Der Bericht beleuchtet die Entwicklung der Fernseh- und Rundfunknetze im Osten Deutschlands ab Anfang der 50er Jahre. Neben einer ausführlichen Darstellung der technischen Aspekte liegt ein weiterer Schwerpunkt auf der Darstellung der nötigen Zusammenarbeit mit den Arbeitsgruppen der angrenzenden Länder. Diese war, bedingt durch die politische Lage, gerade mit den Experten aus Westdeutschland oft schwierig. Die maßgeblich beteiligten Personen und ihre Arbeiten werden vorgestellt. Der Autor war in leitender Position an der Entwicklung in Ostdeutschland beteiligt und liefert mit diesem Bericht einen aus technischer und historischer Sicht wertvollen Beitrag zur Entwicklung des Rundfunks.

Beschreibung: Proposal for scalable models in EMC simulation Advances in Radio Science, 9, 329-334, 2011 Author(s): Á Leibinger and Á Hajdu In this paper a method "Component Series Modeling" (CoSeMod) is presented. This allows fast and easy implementation of scalable model generations for passive component series based on measurement data or specification provided by manufacturer. These can be used in circuit models for fast EMC analysis and optimization, especially in frequency ranges where conducted emission and susceptibility dominate. EMC tasks require high precision equivalent circuit models of components. Models generated with CoSeMod provide in many cases as high a quality as original (static) models do. One feature of scalability is that new netlisting is not needed after component changes. The process of model creation is based on similarities of the components of the same model series (packaging, manufacturing process, material etcetera). Required equations of the relationship between nominal and parasitic values are calculated by nonlinear regression. Model generation for unknown components of a known series is possible with interpolation. Implementation is possible with relatively simple actions made in circuit simulator Saber. An EMC application example of the implemented model is also shown in this paper.

Beschreibung: Advanced parametrical modelling of 24 GHz radar sensor IC packaging components Advances in Radio Science, 9, 383-389, 2011 Author(s): R. Kazemzadeh, W. John, J. Wellmann, U. B. Bala, and A. Thiede This paper deals with the development of an advanced parametrical modelling concept for packaging components of a 24 GHz radar sensor IC used in automotive driver assistance systems. For fast and efficient design of packages for system-in-package modules (SiP), a simplified model for the description of parasitic electromagnetic effects within the package is desirable, as 3-D field computation becomes inefficient due to the high density of conductive elements of the various signal paths in the package. By using lumped element models for the characterization of the conductive components, a fast indication of the design's signal-quality can be gained, but so far does not offer enough flexibility to cover the whole range of geometric arrangements of signal paths in a contemporary package. This work pursues to meet the challenge of developing a flexible and fast package modelling concept by defining parametric lumped-element models for all basic signal path components, e.g. bond wires, vias, strip lines, bumps and balls.

Beschreibung: Classifying user states in next generation networks Advances in Radio Science, 9, 373-376, 2011 Author(s): Y. He and A. Bilgic In this paper we apply a classification method to learn geographic regions using Location Based Services (LBS) in IP Multimedia Subsystem (IMS). We assume that the information in Local Network (cellular network) can be freely exchanged with Global IP Network (IMS) and the information can be gathered in a data base. LBS in the IMS also provide location information for the data sets. Statistic classification methods are applied to the data sets in the data base. Depending on the information provided by the users, they are divided into different user groups (event classes) using Type Filters (TF). Then discriminant analysis is applied to the position information offered by LBS in IMS to determine the geographic regions of the different classes. The learned geographic regions can be used to inform the users in this region or other regions over IMS. This kind of service can be used for any location-based events.

Beschreibung: Multi beam observations of cosmic radio noise using a VHF radar with beam forming by a Butler matrix Advances in Radio Science, 9, 349-357, 2011 Author(s): T. Renkwitz, W. Singer, R. Latteck, and M. Rapp The Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn started to install a new MST radar on the North-Norwegian island Andøya (69.30° N, 16.04° E) in 2009. The new Middle Atmosphere Alomar Radar System (MAARSY) replaces the previous ALWIN radar which has been successfully operated for more than 10 years. The MAARSY radar provides increased temporal and spatial resolution combined with a flexible sequential point-to-point steering of the radar beam. To increase the spatiotemporal resolution of the observations a 16-port Butler matrix has been built and implemented to the radar. In conjunction with 64 Yagi antennas of the former ALWIN antenna array the Butler matrix simultaneously provides 16 individual beams. The beam forming capability of the Butler matrix arrangement has been verified observing the galactic cosmic radio noise of the supernova remnant Cassiopeia A. Furthermore, this multi beam configuration has been used in passive experiments to estimate the cosmic noise absorption at 53.5 MHz during events of enhanced solar and geomagnetic activity as indicators for enhanced ionization at altitudes below 90 km. These observations are well correlated with simultaneous observations of corresponding beams of the co-located imaging riometer AIRIS (69.14° N, 16.02° E) at 38.2 MHz. In addition, enhanced cosmic noise absorption goes along with enhanced electron densities at altitudes below about 90 km as observed with the co-located Saura MF radar using differential absorption and differential phase measurements.

Beschreibung: Accelerating the numerical computation of indirect lightning effects by means of vector fitting Advances in Radio Science, 9, 323-328, 2011 Author(s): J. Anatzki and F. Gronwald In the context of numerical computation of indirect lightning effects it is customary to use volume-discretizing methods in time domain, such as the Finite Difference Time Domain (FDTD) method, the Finite Integration Technique (FIT), or the Transmission Line Matrix (TLM) method. If standard lightning electromagnetic pulses (LEMPs) of tenths of microseconds duration are used as excitations, these methods require long computation times, as implied by the Courant criterion. It is proposed to use shorter pulse forms and to compare the transfer functions obtained by different pulse durations by means of macromodels that are obtained from the vector fitting method. Numerical computation of lightning related transfer functions of a canonical structure indicate that the duration of the exciting pulse can typically be shortened by at least one order of magnitude if compared to a standard pulse.

Beschreibung: Measurement and evaluation of radar cross section for furniture in an indoor propagation channel Advances in Radio Science, 12, 273-278, 2014 Author(s): M. M. Maw, P. Supanakoon, S. Promwong, and J. Takada This paper has attempted to evaluate the radar cross section (RCS) of two furniture items in an indoor environment in a frequency range of 3–7 GHz of the ultra-wideband (UWB) range. The RCS evaluation is achieved through an extended version of the radar equation that incorporates the channel transfer function of scattering. The time-gating method was applied to remove the multipath effect, a phenomenon which typically occurs in the indoor environment. Two double-ridged waveguide horn antennas for both vertical and horizontal polarizations were used to obtain the transfer function of scattering of the furniture prior to analysis in order to derive their bistatic RCS. The RCS results validate the applicability of the proposed extended radar equation to the indoor propagation prediction.

Beschreibung: An extended mode-matching model for improved relative permittivity measurements using a split-cylinder resonator Advances in Radio Science, 12, 267-272, 2014 Author(s): S. Zinal and U. Arz In this paper we present an extended mode-matching model for a split-cylinder resonator involving TE and TM resonant modes. The new model enhances the known TE 0np mode-matching model by improving mode identification and distortion analysis and providing better frequency range coverage for relative permittivity estimation. In order to verify the new model, measured spectra of several substrate materials are analyzed and the estimation results are compared with those of the TE 0np mode-matching model.

Beschreibung: Ionospheric research in Germany prior to Karl Rawer Advances in Radio Science, 12, 225-230, 2014 Author(s): K. Schlegel This brief historical review summarizes the work and achievements of German researchers on ionospheric problems before Karl Rawer started his scientific career in 1937.

Beschreibung: Planetary radio astronomy: Earth, giant planets, and beyond Advances in Radio Science, 12, 211-220, 2014 Author(s): H. O. Rucker, M. Panchenko, and C. Weber The magnetospheric phenomenon of non-thermal radio emission is known since the serendipitous discovery of Jupiter as radio planet in 1955, opening the new field of "Planetary Radio Astronomy". Continuous ground-based observations and, in particular, space-borne measurements have meanwhile produced a comprehensive picture of a fascinating research area. Space missions as the Voyagers to the Giant Planets, specifically Voyager 2 further to Uranus and Neptune, Galileo orbiting Jupiter, and now Cassini in orbit around Saturn since July 2004, provide a huge amount of radio data, well embedded in other experiments monitoring space plasmas and magnetic fields. The present paper as a condensation of a presentation at the Kleinheubacher Tagung 2013 in honour of the 100th anniversary of Prof. Karl Rawer, provides an introduction into the generation mechanism of non-thermal planetary radio waves and highlights some new features of planetary radio emission detected in the recent past. As one of the most sophisticated spacecraft, Cassini, now in space for more than 16 years and still in excellent health, enabled for the first time a seasonal overview of the magnetospheric variations and their implications for the generation of radio emission. Presently most puzzling is the seasonally variable rotational modulation of Saturn kilometric radio emission (SKR) as seen by Cassini, compared with early Voyager observations. The cyclotron maser instability is the fundamental mechanism under which generation and sufficient amplification of non-thermal radio emission is most likely. Considering these physical processes, further theoretical investigations have been started to investigate the conditions and possibilities of non-thermal radio emission from exoplanets, from potential radio planets in extrasolar systems.

Beschreibung: Probability of occurrence of planetary ionosphere storms associated with the magnetosphere disturbance storm time events Advances in Radio Science, 12, 261-266, 2014 Author(s): T. L. Gulyaeva, F. Arikan, and I. Stanislawska The ionospheric W index allows to distinguish state of the ionosphere and plasmasphere from quiet conditions ( W = 0 or ±1) to intense storm ( W = ±4) ranging the plasma density enhancements (positive phase) or plasma density depletions (negative phase) regarding the quiet ionosphere. The global W index maps are produced for a period 1999–2014 from Global Ionospheric Maps of Total Electron Content, GIM-TEC, designed by Jet Propulson Laboratory, converted from geographic frame (−87.5:2.5:87.5° in latitude, −180:5:180° in longitude) to geomagnetic frame (−85:5:85° in magnetic latitude, −180:5:180° in magnetic longitude). The probability of occurrence of planetary ionosphere storm during the magnetic disturbance storm time, Dst, event is evaluated with the superposed epoch analysis for 77 intense storms (Dst ≤ −100 nT) and 230 moderate storms (−100 〈 Dst ≤ −50 nT) with start time, t 0 , defined at Dst storm main phase onset. It is found that the intensity of negative storm, iW - , exceeds the intensity of positive storm, iW + , by 1.5–2 times. An empirical formula of iW + and iW - in terms of peak Dst is deduced exhibiting an opposite trends of relation of intensity of ionosphere-plasmasphere storm with regard to intensity of Dst storm.

Beschreibung: Extreme ultraviolet (EUV) solar spectral irradiance (SSI) for ionospheric application – history and contemporary state-of-art Advances in Radio Science, 12, 251-260, 2014 Author(s): G. Schmidtke, Ch. Jacobi, B. Nikutowski, and Ch. Erhardt After a historical survey of space related EUV measurements in Germany and the role of Karl Rawer in pursuing this work, we describe present developments in EUV spectroscopy and provide a brief outlook on future activities. The group of Karl Rawer has performed the first scientific space project in Western Europe on 19th October 1954. Then it was decided to include the field of solar EUV spectroscopy in ionospheric investigations. Starting in 1957 an intensified development of instrumentation was going on to explore solar EUV radiation, atmospheric airglow and auroral emissions until the institute had to stop space activities in the early nineteen-eighties. EUV spectroscopy was continued outside of the institute during eight years. This area of work was supported again by the institute developing the Auto-Calibrating Spectrometers (SolACES) for a mission on the International Space Station (ISS). After more than six years in space the instrument is still in operation. Meanwhile the work on the primary task also to validate EUV data available from other space missions has made good progress. The first results of validating those data and combine them into one set of EUV solar spectral irradiance are very promising. It will be recommended for using it by the science and application community. Moreover, a new low-cost type of an EUV spectrometer is presented for monitoring the solar EUV radiation. It shall be further developed for providing EUV-TEC data to be applied in ionospheric models replacing the Covington index F 10.7 . Applying these data for example in the GNSS signal evaluation a more accurate determination of GNSS receiver positions is expected for correcting the propagation delays of navigation signals traveling through the ionosphere from space to earth. – Latest results in the field of solar EUV spectroscopy are discussed, too.

Beschreibung: Kleinheubach-U.R.S.I.: 48~years home for the German-Austrian Beacon Satellite Community (BSC) Advances in Radio Science, 12, 237-239, 2014 Author(s): G. K. Hartmann No abstract available.

Beschreibung: Remote sensing and modeling of lightning caused long recovery events within the lower ionosphere using VLF/LF radio wave propagation Advances in Radio Science, 12, 241-250, 2014 Author(s): E. D. Schmitter On the 4 November 2012 at 3:04:27 UT a strong lightning in the midst of the North Sea affected the propagation conditions of VLF/LF transmitter radio signals from NRK (Iceland, 37.5 kHz) and GBZ (UK, 19.58 kHz) received at 5246° N 8° E (NW Germany). The amplitude and phase dips show a recovery time of 6–12 min pointing to a LOng Recovery Early VLF (LORE) event. Clear assignment of the causative return stroke in space and time was possible with data from the WWLLN (Worldwide Lightning Location Network). Based on a return stroke current model the electric field is calculated and an excess electron density distribution which decays over time in the lower ionosphere is derived. Ionization, attachment and recombination processes are modeled in detail. Entering the electron density distribution in VLF/LF radio wave propagation calculations using the LWPC (Long Wavelength Propagation Capability) code allows to model the VLF/LF amplitude and phase behavior by adjusting the return stroke current moment. The results endorse and quantify the conception of lower ionosphere EMP heating by strong – but not necessarily extremely strong – return strokes of both polarities.

Beschreibung: Karl Rawer: space research and international cooperation – Laudation on the occasion of the 100 th birthday of Professor Karl Rawer Advances in Radio Science, 12, 221-223, 2014 Author(s): B. W. Reinisch This laudation is given in honor of the 100 th birthday of Prof. Karl Rawer which happens to coincide with the 45th anniversary of the International Reference Ionosphere (IRI). The ionosphere was discovered during Karl Rawer's lifetime, and he has dedicated his professional life to its exploration. World Wars I and II shaped his early life, but they also launched his career as one of the eminent geophysical scientists of the twentieth century. The paper looks back at Karl Rawer's life and his pioneering work and leadership in advancing and shaping the exploration of the ionosphere.

Beschreibung: The International Reference Ionosphere: Rawer's IRI and its status today Advances in Radio Science, 12, 231-236, 2014 Author(s): D. Bilitza When the Committee on Space Research (COSPAR) initiated the International Reference Ionosphere (IRI) project in 1968 it wisely selected K. Rawer as its first Chairperson. With a solid footing and good contacts in both the ground-based and space-based ionospheric communities he was ideally suited to pull together colleagues and data from both communities to help build the first version of the IRI. He assembled a team of 20+ international ionospheric experts in the IRI Working Group and chaired and directed the group from 1968 to 1984. The working group has now grown to 63 members and the IRI model has undergone many revisions as new data became available and new modeling techniques were applied. This paper was presented during a special session of the Kleinheubach Tagung 2013 in honor of K. Rawer's 100th birthday. It will review the current status of the IRI model and project and the international recognition it has achieved. It is quite fitting that this year we not only celebrate K. Rawer's 100th birthday but also the exciting news that his favorite science endeavor, IRI, has been internationally recognized as an ISO (International Standardization Organization) standard. The IRI homepage is at http://irimodel.org .

Beschreibung: 〈b〉Crosstalk Cancellation in Inductively Coupled Full-Duplex Data Transfer Systems by a single Multipole Dualport Coil Structure〈/b〉〈br〉 Christian Schmidt, Martin Buchholz, and Madhukar Chandra〈br〉 Adv. Radio Sci., 16, 29-34, https://doi.org/10.5194/ars-16-29-2018, 2018〈br〉 The current work presents a structure that can be used in magnetically coupled bi-directional data transfer structures. It allows for high-speed data transfer with high decoupling between both data channels and thus provides a highly reliable data link. The principal used to achieve the decoupling is the cancellation of magnetic fields generated by one part of the structure in the other part and vice versa. Three dimensional field simulations and measurements at a prototype were conducted.

Beschreibung: 〈b〉Design and implementation of a flexible node for IoT supporting 6LoWPAN and a sensor shield for home automation application〈/b〉〈br〉 Josua Arndt, Tim Lauber, Ralf Wunderlich, and Stefan Heinen〈br〉 Adv. Radio Sci., 16, 67-75, https://doi.org/10.5194/ars-16-67-2018, 2018〈br〉 The Internet of Things (IoT) and Industry 4.0 is evolving and has a high demand for reliable electronics. The topic is the development of a radio communication system regarding the requirements for the end user and concerning a high flexibility of the application. The result is a core board which can be combined with different sensor or actor shields to increase the flexibility and re-usability.

Beschreibung: 〈b〉Where to go from here? New cross layer techniques for LTE Turbo-Code decoding at high code rates〈/b〉〈br〉 Stefan Weithoffer and Norbert Wehn〈br〉 Adv. Radio Sci., 16, 77-87, https://doi.org/10.5194/ars-16-77-2018, 2018〈br〉 〈p〉The wide range of code rates and code block sizes supported by todays wireless communication standards, together with the requirement for a throughput in the order of Gbps, necessitates sophisticated and highly parallel channel decoder architectures. Code rates specified in the LTE standard, which uses Turbo-Codes, range up to 〈i〉r〈/i〉 = 0.94 to maximize the information throughput by transmitting only a minimum amount of parity information, which negatively impacts the error correcting performance. This especially holds for highly parallel hardware architectures. Therefore, the error correcting performance must be traded-off against the degree of parallel processing.〈/p〉 〈p〉State-of-the-art Turbo-Code decoder hardware architectures are optimized on code block level to alleviate this trade-off. In this paper, we follow a cross-layer approach by combining system level knowledge about the rate-matching and the transport block structure in LTE with the bit-level technique of on-the-fly CRC calculation. Thereby, our proposed Turbo-Code decoder hardware architecture achieves coding gains of 0.4–1.8 dB compared to state-of-the-art accross a wide range of code block sizes.〈/p〉 〈p〉For the fully LTE compatible Turbo-Code decoder, we demonstrate a negligible hardware overhead and a resulting high area and energy efficiency and give post place and route synthesis numbers.〈/p〉

Beschreibung: 〈b〉Measurement Uncertainty of Radiated Electromagnetic Emissions in In Situ Tests of Wind Energy Conversion Systems〈/b〉〈br〉 Sebastian Koj, Axel Hoffmann, and Heyno Garbe〈br〉 Adv. Radio Sci., 16, 13-22, https://doi.org/10.5194/ars-16-13-2018, 2018〈br〉 〈p〉The electromagnetic (EM) emissions of wind energy conversion systems (WECS) are evaluated in situ. Results of in situ tests, however, are only valid for the examined equipment under test (EUT) and cannot be applied to series production as samples, as the measurement uncertainty for in situ environment is not characterized. Currently measurements must be performed on each WECS separately, this is associated with significant costs and time requirement to complete. Therefore, in this work, based on the standard procedure according to the 〈q〉Guide to the Expression of Uncertainty〈/q〉 (GUM, 2008) the measurement uncertainty is characterized. From current normative situation obtained influences on the measurement uncertainty: wind velocity and undefined ground are evaluated. The influence of increased wind velocity on the measurement uncertainty is evaluated with an analytical approach making use of the dipole characteristic. A numerically evaluated model provides information about the expected uncertainty due to reflection on different textures and varying values of relative ground moisture. Using a classical reflection law based approach, the simulation results are validated. Thanks to the presented methods, it is possible to successfully characterize the measurement uncertainty of in situ measurements of WECS's EM emissions.〈/p〉

Beschreibung: 〈b〉Humidity and temperature sensor system demonstrator with NFC tag for HySiF applications〈/b〉〈br〉 Amro Eldebiky, Mourad Elsobky, Harald Richter, and Joachim N. Burghartz〈br〉 Adv. Radio Sci., 16, 109-116, https://doi.org/10.5194/ars-16-109-2018, 2018〈br〉 Hybrid System-in-Foil (HySiF) is one of the emerging branches of flexible electronics in which ultra-thin silicon chips are integrated with flexible sensors in polymeric foils. Intensive attention was given to the implementation of flexible environmental sensing platforms for logistics and food packaging. The aim of this work is the implementation of a sensor system demonstrator using HySiF components: an ultra-thin microcontroller chip, an on-chip temperature, and an on-foil humidity sensors.

Beschreibung: 〈b〉Polar Code decoder exploration framework〈/b〉〈br〉 Claus Kestel, Stefan Weithoffer, and Norbert Wehn〈br〉 Adv. Radio Sci., 16, 43-50, https://doi.org/10.5194/ars-16-43-2018, 2018〈br〉 We present a modular framework to automatically generate and evaluate a wide range of Polar Code decoders, with emphasis on design space exploration for efficient hardware architectures. To demonstrate the efficiency of our framework a very high throughput SCAN Polar Code decoder is shown that was automatically generated. This decoder is, to the best of our knowledge, the fastest SCAN Polar Code decoder published so far.

Beschreibung: 〈b〉The response of nonlinearly loaded antennas to repetitive HPEM excitations as obtained from equivalent circuit models〈/b〉〈br〉 Devanand Palur Palanivelu, Robert Michels, Matthias Kreitlow, and Frank Gronwald〈br〉 Adv. Radio Sci., 16, 135-140, https://doi.org/10.5194/ars-16-135-2018, 2018〈br〉 In this contribution the effects of repetitive pulse excitations on linearly and nonlinearly loaded antennas are studied on the basis of equivalent circuit models. This is important to understand in the context of Electromagnetic Compatibility possible nonlinear effects which often are not included in the analysis. It is found that a surprisingly large capacitive effect can be produced which has no counterpart in the linear case and is accompanied by the storage of unwanted electric energy.

Beschreibung: 〈b〉Order reduction of hierarchical interconnected dynamical systems〈/b〉〈br〉 Michael Popp and Wolfgang Mathis〈br〉 Adv. Radio Sci., 16, 89-97, https://doi.org/10.5194/ars-16-89-2018, 2018〈br〉 The simulation of large scale nonlinear dynamical interconnected systems is a usual task. Due to the high complexity of the considered systems, the principle of thinking in hierarchical structures is common among engineers. This contribution proposes an approach for the numerical simulation of large systems, which keeps the hierarchical system structure alive during the entire simulation and order reduction process, which results in several benefits compared with the state of the art.

Beschreibung: 〈b〉Forcing mechanisms of the 6 h tide in the mesosphere/lower thermosphere〈/b〉〈br〉 Christoph Jacobi, Christoph Geißler, Friederike Lilienthal, and Amelie Krug〈br〉 Adv. Radio Sci., 16, 141-147, https://doi.org/10.5194/ars-16-141-2018, 2018〈br〉 The possible sources of the quarterdiurnal tide (QDT) in the middle atmosphere are still under discussion. Therefore, meteor radar winds were analyzed with respect to non-linear interaction, which probably plays a role in winter, but to a lesser degree in summer. Numerical model experiments lead to the conclusion that, although non-linear tidal interaction is indeed one source of the QDT, the major source is direct solar forcing of the 6-hr tidal components.

Beschreibung: 〈b〉Ionospheric response to solar EUV variations: Preliminary results〈/b〉〈br〉 Rajesh Vaishnav, Christoph Jacobi, Jens Berdermann, Erik Schmölter, and Mihail Codrescu〈br〉 Adv. Radio Sci., 16, 157-165, https://doi.org/10.5194/ars-16-157-2018, 2018〈br〉 We investigate the ionospheric response to solar Extreme Ultraviolet (EUV) variations using different solar proxies and IGS TEC maps. An ionospheric delay in GTEC is observed at the 27 days solar rotation period with the time scale of about ~ 1–2 days. Here we present preliminary results from the CTIPe model simulations which qualitatively reproduce the observed ~1-2 days delay in GTEC, which is might be due to vertical transport processes.

Beschreibung: 〈b〉IRI the International Standard for the Ionosphere〈/b〉〈br〉 Dieter Bilitza〈br〉 Adv. Radio Sci., 16, 1-11, https://doi.org/10.5194/ars-16-1-2018, 2018〈br〉 This paper gives a brief overview over the International Reference Ionosphere (IRI) project and model. IRI is recognized as the official standard for the ionosphere by the International Standardization Organization (ISO). Of great importance are the external drivers of the model that help IRI to represent ionospheric conditions as realistically as possible. The paper discusses the solar and ionospheric measurements that are used as drivers and presents recent improvements and changes.

Beschreibung: 〈b〉High-Speed Serializer for a 64 GS s〈sup〉−1〈/sup〉 Digital-to-Analog Converter in a 28 nm Fully-Depleted Silicon-on-Insulator CMOS Technology〈/b〉〈br〉 Daniel Widmann, Markus Grözing, and Manfred Berroth〈br〉 Adv. Radio Sci., 16, 99-108, https://doi.org/10.5194/ars-16-99-2018, 2018〈br〉 Digital-to-analog converters (DACs) with very high conversion rates and bandwidth are of special interest for optical coherent transceiver systems and arbitrary waveform generators. An attractive solution to provide several channels with very high data rates of tens of Gbit/s is to use a high speed serializer. We present a CMOS serializer consisting of a 19 channel 16:1 multiplexer (MUX) for output data rates up to 64 Gbit/s per channel and a low skew clock distribution network.

Beschreibung: 〈b〉Near Infrared Diode Laser THz Systems〈/b〉〈br〉 Carsten Brenner, Yinghui Hu, Jared Gwaro, Nils Surkamp, Benjamin Döpke, Martin R. Hofmann, Besher Kani, Andreas Stöhr, Bernd Sumpf, Andreas Klehr, and Jörg Fricke〈br〉 Adv. Radio Sci., 16, 167-175, https://doi.org/10.5194/ars-16-167-2018, 2018〈br〉 The generation and detection of radiation in the THz frequency range can be achieved with many different electronic and photonic concepts. Among the many different photonic THz systems the most versatile are based on diode lasers. In this paper we describe and review the different concepts and optimization ideas for diode laser based THz systems in order to achieve the best performance for different types of THz setups.

Beschreibung: 〈b〉Influence of an Electrically Non-Conducting Heat Sink for Power Semiconductors on Radiated Interferences〈/b〉〈br〉 Stephan Chromy, Kai Rathjen, Sebastian Fahlbusch, Klaus F. Hoffmann, and Stefan Dickmann〈br〉 Adv. Radio Sci., 16, 117-122, https://doi.org/10.5194/ars-16-117-2018, 2018〈br〉 For energy efficient power conversion, fast switching power semiconductors are used within power electronics. The switching can lead to disturbances of other electrical devices because of interference on the power line and in the air. The common aluminium heat sinks for the cooling of the power semiconductors are electrically conductive and lead to more interference. Using an electrically isolating ceramic heat sink is an approach to reduce the interference from the heat sink.

Beschreibung: 〈b〉Modeling and Simulation of stochastically deformed Waveguides using Schelkunoff's Method〈/b〉〈br〉 Hoang Duc Pham, Soeren Ploennigs, and Wolfgang Mathis〈br〉 Adv. Radio Sci., 16, 35-41, https://doi.org/10.5194/ars-16-35-2018, 2018〈br〉 This paper deals with the propagation of electromagnetic waves in cylindrical waveguides with irregularly deformed cross-sections. Waveguides are of high interest because of its practical use as a transmission medium. Schelkunoff's method, is a semi-analytical method for computing electromagnetic waves in hollow and cylindrical waveguides bounded by PEC walls. The aim of this paper is to derive the so-called GTE's for irregular deformed waveguides.

Beschreibung: 〈b〉Using The Kramers-Kronig Transforms To Retrieve The Conductivity From The Effective Complex Permittivity〈/b〉〈br〉 Mostafa Bakry and Ludger Klinkenbusch〈br〉 Adv. Radio Sci., 16, 23-28, https://doi.org/10.5194/ars-16-23-2018, 2018〈br〉 A relatively simple numerical method is introduced to separate the electric conductivity from the effective (complex) permittivity. The latter is often the outcome of measurements of the electric properties of a material. The method includes a numerical evaluation of the Kramers-Kronig transform integrals also known as Hilbert transform. Exemplarily it is applied to extract the conductivity from measured data found in the literature describing the effective permittivity of composite material.

Beschreibung: 〈b〉Future integrated communication network architectures enabling heterogeneous service provision〈/b〉〈br〉 Paul Arnold and Dirk von Hugo〈br〉 Adv. Radio Sci., 16, 59-66, https://doi.org/10.5194/ars-16-59-2018, 2018〈br〉 During the recently successfully completed EU funded cooperative research project 5G NORMA a new and-to-end network concept for future integrated communication network architectures (known as 5G) has been proposed and analyzed. Such architecture allows to support multiple services and tenants according to their specific needs – based on a common jointly used and dynamically configured infrastructure. Flexibility and adaptability to meet demands of future 5G use cases could be proven.

Beschreibung: 〈b〉A digital receiver signal strength detector for multi-standard low-IF receivers〈/b〉〈br〉 Tobias Saalfeld, Tobias Piwczyk, Ralf Wunderlich, and Stefan Heinen〈br〉 Adv. Radio Sci., 16, 51-57, https://doi.org/10.5194/ars-16-51-2018, 2018〈br〉 With the increasing amount of mobile communication, special care has to be taken to avoid collision on wireless channels. The received power in the desired band is an indicator for the utilization of this frequency range. On a receiver several ways of detecting a Received Signal Strength Indicator are available, but don't necessarily fulfill efficiency or precision requirements. Therefore, this work presents a digital implementation which is both energy efficient and precise enough.

Beschreibung: 〈b〉Delayed response of the ionosphere to solar EUV variability〈/b〉〈br〉 Erik Schmölter, Jens Berdermann, Norbert Jakowski, Christoph Jacobi, and Rajesh Vaishnav〈br〉 Adv. Radio Sci., 16, 149-155, https://doi.org/10.5194/ars-16-149-2018, 2018〈br〉 Physical and chemical processes in the ionosphere are driven by complex interactions with the solar radiation. The ionospheric plasma is in particular sensitive to solar variations with a time delay between one and two days. Here we present preliminary results of the ionospheric delay based on a comprehensive and reliable database consisting of GNSS TEC Maps and EUV spectral flux data.

Beschreibung: Investigations on the magnetic field coupling of automotive high voltage systems to determine relevant parameters for an EMR-optimized designing David Krause, Werner John, and Robert Weigel Adv. Radio Sci., 13, 269-278, doi:10.5194/ars-13-269-2016, 2016 The implementation of electrical drive trains in modern vehicles is a new challenge for EMC development. One crucial issue is the appearance of magnetic fields, which need to be limited due to legal regulations. This contribution therefore depicts a variety of investigations on magnetic field coupling of automotive high-voltage systems. Within the scope of a comprehensive analysis decisive influence quantities are stated and design rules with regard to minimized magnetic fields are discussed.

Beschreibung: Terdiurnal signatures in sporadic E layers at midlatitudes Advances in Radio Science, 11, 333-339, 2013 Author(s): T. Fytterer, C. Arras, and C. Jacobi Global Positioning System radio occultation measurements by the FORMOsa SATellite mission-3/Constellation Observing System for Meteorology, Ionosphere and Climate satellites were used to analyse the behaviour of the signature of the terdiurnal tide in sporadic E ( E S ) layers at midlatitudes (43–63° N). According to theory, the occurrence of E S is expected when the vertical zonal wind shear, which is mainly owing to solar tides, is negative. 4 yr means, based on 3-monthly running mean zonal means from December 2006–November 2010, were constructed for the terdiurnal oscillation in the occurrence frequency of E S . Comparison of the results with VHF meteor radar observations of the terdiurnal tide and the 8 h oscillation in the vertical zonal wind shear at Collm, Germany (51.3° N, 13° E) shows a clear correspondence between the 8 h in E S and in wind shear signature.

Beschreibung: Investigation of horizontal structures at mesospheric altitudes using coherent radar imaging Advances in Radio Science, 11, 319-325, 2013 Author(s): S. Sommer, G. Stober, C. Schult, M. Zecha, and R. Latteck The Middle Atmosphere Alomar Radar System (MAARSY) in Northern Norway (69.30°N, 16.04°E) was used to perform interferometric observations of Polar Mesosperic Summer Echoes (PMSE) in June 2012. Coherent Radar Imaging (CRI) using Capon's method was applied allowing a high spatial resolution. The algorithm was validated by simulation and trajectories of meteor head echoes. Both data sets show a good correspondence with the algorithm. Using this algorithm, the aspect sensitivity of PMSE was analysed in a case study, making use of the capability of CRI to resolve the pattern within the beam volume. No correction of the beam pattern was made yet. It was found in this case study, that no large variations in the scattering width and the scattering center occured apart from a very short period of time at the upper edge of the PMSE.

Beschreibung: Quantitative data analysis of ESAR data Advances in Radio Science, 11, 291-295, 2013 Author(s): N. Phruksahiran and M. Chandra A synthetic aperture radar (SAR) data processing uses the backscattered electromagnetic wave to map radar reflectivity of the ground surface. The polarization property in radar remote sensing was used successfully in many applications, especially in target decomposition. This paper presents a case study to the experiments which are performed on ESAR L-Band full polarized data sets from German Aerospace Center (DLR) to demonstrate the potential of coherent target decomposition and the possibility of using the weather radar measurement parameter, such as the differential reflectivity and the linear depolarization ratio to obtain the quantitative information of the ground surface. The raw data of ESAR has been processed by the SAR simulator developed using MATLAB program code with Range-Doppler algorithm.

Beschreibung: New experiments to validate the radiation pattern of the Middle Atmosphere Alomar Radar System (MAARSY) Advances in Radio Science, 11, 283-289, 2013 Author(s): T. Renkwitz, G. Stober, R. Latteck, W. Singer, and M. Rapp The Middle Atmosphere Alomar Radar System (MAARSY) is a monostatic radar with an active phased array antenna designed for studies of phenomena in the mesosphere and lower thermosphere. Its design in particular the flexible beam forming and steering capability makes it to a powerful instrument to perform observations with high angular and temporal resolution. The knowledge of the actual radiation pattern is crucial to configure and analyze experiments carried out with the radar. The simulated radiation pattern is evaluated by the observation of cosmic radio emissions which are compared to a Global Sky temperature Maps model consisting of the most recent, thorough and accurate radio astronomy surveys. Additionally to these passive receive-only experiments active two-way experiments are presented, which corroborate the findings of the passive experiments.

Beschreibung: Single-element based ultra-wideband antenna array concepts for wireless high-precision 2-D local positioning Advances in Radio Science, 11, 297-305, 2013 Author(s): M. Gardill, G. Fischer, R. Weigel, and A. Koelpin We generally categorize the approaches for ultra-wideband antenna array design, and consequently propose simplified concepts for antenna arrays for a high-precision, ultra-wideband FMCW radar 2-D local positioning system to obtain robustness against multi path interference, perform angle of arrival analysis, as well as instantaneous heading estimation. We focus on low-cost and mechanical robust, industrial-application ready antennas. The antenna arrays are optimized for operation in the 5 GHz to 8 GHz frequency range and are designed towards supporting full omnidirectional 360° as well as partial half-plane direction of arrival estimation. Two different concepts for vehicle- as well as wall-mounted antenna array systems are proposed and discussed. We propose a wideband unidirectional bow-tie antenna array element having 97% impedance and 37% pattern bandwidth and a robust vehicle mounted omnidirectional antenna element having more than 85% impedance and pattern bandwidth.

Beschreibung: Application of postured human model for SAR measurements Advances in Radio Science, 11, 347-352, 2013 Author(s): M. Vuchkovikj, I. Munteanu, and T. Weiland In the last two decades, the increasing number of electronic devices used in day-to-day life led to a growing interest in the study of the electromagnetic field interaction with biological tissues. The design of medical devices and wireless communication devices such as mobile phones benefits a lot from the bio-electromagnetic simulations in which digital human models are used. The digital human models currently available have an upright position which limits the research activities in realistic scenarios, where postured human bodies must be considered. For this reason, a software application called "BodyFlex for CST STUDIO SUITE" was developed. In its current version, this application can deform the voxel-based human model named HUGO (Dipp GmbH, 2010) to allow the generation of common postures that people use in normal life, ensuring the continuity of tissues and conserving the mass to an acceptable level. This paper describes the enhancement of the "BodyFlex" application, which is related to the movements of the forearm and the wrist of a digital human model. One of the electromagnetic applications in which the forearm and the wrist movement of a voxel based human model has a significant meaning is the measurement of the specific absorption rate (SAR) when a model is exposed to a radio frequency electromagnetic field produced by a mobile phone. Current SAR measurements of the exposure from mobile phones are performed with the SAM (Specific Anthropomorphic Mannequin) phantom which is filled with a dispersive but homogeneous material. We are interested what happens with the SAR values if a realistic inhomogeneous human model is used. To this aim, two human models, a homogeneous and an inhomogeneous one, in two simulation scenarios are used, in order to examine and observe the differences in the results for the SAR values.

Beschreibung: Enhanced sporadic E occurrence rates during the Geminid meteor showers 2006–2010 Advances in Radio Science, 11, 313-318, 2013 Author(s): C. Jacobi, C. Arras, and J. Wickert Northern Hemisphere midlatitude sporadic E ( E s ) layer occurrence rates derived from FORMOSAT-3/COSMIC GPS radio occultation (RO) measurements during the Geminid meteor showers 2006–2010 are compared with meteor rates obtained with the Collm (51.3° N, 13.0° E) VHF meteor radar. In most years, E s rates increase after the shower, with a short delay of few days. This indicates a possible link between meteor influx and the production of metallic ions that may form E s . There is an indication that the increase propagates downward, probably partly caused by tidal wind shear. However, the correlation between E s rates and meteor flux varies from year to year. A strong correlation is found especially in 2009, while in 2010 E s rates even decrease during the shower. This indicates that additional processes significantly influence E s occurrence also during meteor showers. A possible effect of the semidiurnal tide is found. During years with weaker tidal wind shear, the correlation between E s and meteor rates is even weaker.

Beschreibung: Comparison of the Extended Kalman Filter and the Unscented Kalman Filter for Magnetocardiography activation time imaging Advances in Radio Science, 11, 341-346, 2013 Author(s): H. Ahrens, F. Argin, and L. Klinkenbusch The non-invasive and radiation-free imaging of the electrical activity of the heart with Electrocardiography (ECG) or Magnetocardiography (MCG) can be helpful for physicians for instance in the localization of the origin of cardiac arrhythmia. In this paper we compare two Kalman Filter algorithms for the solution of a nonlinear state-space model and for the subsequent imaging of the activation/depolarization times of the heart muscle: the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). The algorithms are compared for simulations of a (6×6) magnetometer array, a torso model with piecewise homogeneous conductivities, 946 current dipoles located in a small part of the heart (apex), and several noise levels. It is found that for all tested noise levels the convergence of the activation times is faster for the UKF.

Beschreibung: Data analysis of low frequency transmitter signals received at a midlatitude site with regard to planetary wave activity Advances in Radio Science, 10, 279-284, 2012 Author(s): E. D. Schmitter More than 2 yr of continuously recorded signal amplitude data from the MSK transmitters NRK/TFK (37.5 kHz, Iceland) and NSY (45.9 kHz, Sicily) received at (52° N 8° E) in the time range from August 2009 to September 2011 are analyzed with regard to planetary wave activity. Wavelet analysis of the day/night amplitude ratio reveals clear evidence of quasi 16 day periods mainly during winter time as well as traces of 5 and 10 day periods on both paths. The amplitude ratio is well correlated to the typical stratospheric (10 hPa) seasonal temperature profile – more clearly to be seen on the northern path. The results are in line and an extension of manifold research with regard of ionospheric absorption phenomena caused by atmospheric wave activity. Continuous monitoring of transmitters in the 40 kHz frequency range proved as an inexpensive tool for investigating mesospheric response to forcing from below.

Beschreibung: Statistics of long-term ionospheric measurements Advances in Radio Science, 10, 255-258, 2012 Author(s): T. Damboldt and P. Suessmann It is shown that after elimination of the dominant influence of solar activity, the height hmF2 of the maximum ionisation of the ionosphere (which is inversely linearly related to M(3000)F2 as described for example by the Shimazaki formula) shows a marked decrease during the recent solar minimum (2005 to 2009) of about 20 km. This is in accordance with results of studies of the decreased neutral density of the lower thermosphere and the density decrease at about 400 km during the unusual recent solar minimum. It is also shown that there is a trend reversal in the height of the ionosphere hmF2 in about 1963/1964 with a negative trend from 1942 to 1963 and a positive trend from 1964 to 2005. This is in contrast to the results reported in most other publications of ionospheric long-term trends. There is no significant trend in foF2 and, particularly, none of the effects described above for hmF2 could be found in foF2.

Beschreibung: Numerical modeling of solar wind influences on the dynamics of the high-latitude upper atmosphere Advances in Radio Science, 10, 299-312, 2012 Author(s): M. Förster, B. E. Prokhorov, A. A. Namgaladze, and M. Holschneider Neutral thermospheric wind patterns at high latitudes obtained from cross-track acceleration measurements of the CHAMP satellite above both polar regions are used to deduce statistical neutral wind vorticity distributions and were analyzed in their dependence on the Interplanetary Magnetic Field (IMF). The average pattern confirms the large duskside anticyclonic vortex seen in the average wind pattern and reveals a positive (cyclonic) vorticity on the dawnside, which is almost equal in magnitude to the duskside negative one. The IMF dependence of the vorticity pattern resembles the characteristic field-aligned current (FAC) and ionospheric plasma drift pattern known from various statistical studies obtained under the same sorting conditions as, e.g., the EDI Cluster statistical drift pattern. There is evidence for hemispheric differences in the average magnitudes of the statistical patterns both for plasma drift and even more for the neutral wind vorticity. The paper aims at a better understanding of the globally interconnected complex plasma physical and electrodynamic processes of Earth's upper atmosphere by means of first-principle numerical modeling using the Upper Atmosphere Model (UAM). The simulations of, e.g., thermospheric neutral wind and mass density at high latitudes are compared with CHAMP observations for varying IMF conditions. They show an immediate response of the upper atmosphere and its high sensitivity to IMF changes in strength and orientation.