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  • 11
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    Model of the Radio Frequency (RF) Excitation Response from Monopole and Dipole Antennas in a Large Scale Tank (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Good antenna-mode coupling is needed for determining the amount of propellant in a tank through the method of radio frequency mass gauging (RFMG). The antenna configuration and position in a tank are important factors in coupling the antenna to the natural electromagnetic modes. In this study, different monopole and dipole antenna mounting configurations and positions were modeled and responses simulated in a full-scale tank model with the transient solver of CST Microwave Studio (CST Computer Simulation Technology of America, Inc.). The study was undertaken to qualitatively understand the effect of antenna design and placement within a tank on the resulting radio frequency (RF) tank spectrum.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-2012-217267 , E-18022
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 12
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    Simulating Global AeroMACS Airport Ground Station Antenna Power Transmission Limits to Avoid Interference With Mobile Satellite Service Feeder Uplinks (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: The Aeronautical Mobile Airport Communications System (AeroMACS), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low Earth orbit from transmitters at global airports was simulated with the Visualyse Professional software. The dependence of the interference power on antenna distribution, gain patterns, duty cycle, and antenna tilt was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power from global airports required to maintain the cumulative interference power under the established threshold.
    Keywords: Communications and Radar
    Type: NASA/TP-2013-216480 , E-18566 , GRC-E-DAA-TN6942
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 13
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    Magnetic Tunnel Junction-Based On-Chip Microwave Phase and Spectrum Analyzer (2014)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A magnetic tunnel junction (MTJ)-based microwave detector is proposed and investigated. When the MTJ is excited by microwave magnetic fields, the relative angle between the free layer and pinned layer alternates, giving rise to an average resistance change. By measuring the average resistance change, the MTJ can be utilized as a microwave power sensor. Due to the nature of ferromagnetic resonance, the frequency of an incident microwave is directly determined. In addition, by integrating a mixer circuit, the MTJ-based microwave detector can also determine the relative phase between two microwave signals. Thus, the MTJbased microwave detector can be used as an on-chip microwave phase and spectrum analyzer.
    Keywords: Instrumentation and Photography; Communications and Radar
    Type: NASA/TM-2014-218305 , E-18906 , GRC-E-DAA-TN13799
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 14
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    Space-Qualified Traveling-Wave Tube (2010)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: The L-3 Communications Electron Technologies, Inc. Model 999HA traveling-wave tube (TWT), was developed for use as a high-power microwave amplifier for high-rate transmission of data and video signals from deep space to Earth (see figure). The 999HA is a successor to the 999H a non-space qualified TWT described in High-Power, High-Efficiency Ka-Band Traveling-Wave Tube (LEW-17900-1), NASA Tech Briefs, Vol. 31, No. 2 (February 2007), page 32. Operating in the 31.8-to-32.3 GHz frequency band, the 999HA has been shown to generate 252 W of continuous- wave output power at 62 percent overall power efficiency a 75-percent increase in output power over the 999H. The mass of the 999HA is 35 percent less than that of the 999H. Moreover, taking account of the elimination of a Faraday cage that is necessary for operation of the 999H but is obviated by a redesign of high-voltage feed-throughs for the 999HA, the overall reduction in mass becomes 57 percent with an 82 percent reduction in volume. Through a series of rigorous tests, the 999HA has been qualified for operation aboard spacecraft with a lifetime exceeding seven years. Offspring of the 999HA will fly on the Kepler and Lunar Reconnaissance Orbiter missions.
    Keywords: Man/System Technology and Life Support
    Type: LEW-18220-1 , NASA Tech Briefs, March 2010; 9
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 15
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    Investigating Dielectric and Metamaterial Effects in a Terahertz Traveling-Wave Tube Amplifier (2008)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Adding material enhancements to a terahertz traveling-wave tube amplifier is investigated. Isotropic dielectrics, negative-index metamaterials, and anisotropic crystals are simulated, and plans to increase the efficiency of the device are discussed. Early results indicate that adding dielectric to the curved sections of the serpentine-shaped slow-wave circuit produce optimal changes in the cold-test characteristics of the device and a minimal drop in operating frequency. Additional results suggest that materials with simultaneously small relative permittivities and electrical conductivities are best suited for increasing the efficiency of the device. More research is required on the subject, and recommendations are given to determine the direction.
    Keywords: Electronics and Electrical Engineering
    Type: NASA/TM-2008-215059 , E-16271
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 16
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    Application of Multihop Relay for Performance Enhancement of AeroMACS Networks (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091-5150 MHz has been created by ITU to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.
    Keywords: Communications and Radar
    Type: E-18335-1 , 2012 Integrated Communications, Navigation, and Surveillance Conference; Apr 24, 2012 - Apr 26, 2012; Herndon, VA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 17
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    Dependence of AeroMACS Interference on Airport Radiation Pattern Characteristics (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: AeroMACS (Aeronautical Mobile Airport Communications System), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service (MSS) feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low earth orbit from AeroMACS transmitters at the 497 major airports in the contiguous United States was simulated with the Visualyse Professional software. The dependence of the interference power on the number of antenna beams per airport, gain patterns, and beam direction orientations was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power required to maintain the cumulative interference power under the established threshold.
    Keywords: Aircraft Communications and Navigation
    Type: NASA/TM-2012-217657 , E-18334 , Integrated Communications, Navigation and Surveillance (ICNS) 2012 Conference; Apr 24, 2012 - Apr 26, 2012; Herndon, VA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 18
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    Application of Multihop Relay for Performance Enhancement of AeroMACS Networks (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091 to 5150 MHz has been created by International Telecommunications Union (ITU) to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.
    Keywords: Aircraft Communications and Navigation
    Type: NASA/TM-2012-217658 , E-18335 , Integrated Communications, Navigation and Surveillance (ICNS) 2012 Conference; Apr 24, 2012 - Apr 26, 2012; Herndon, VA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 19
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    Interference Analysis for an Aeronautical Mobile Airport Communications System (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The next generation of aeronautical communications for airport surface applications has been identified through a NASA research program and an international collaborative future communications study. The result, endorsed by both the United States and European regulatory agencies is called AeroMACS (Aeronautical Mobile Airport Communications System) and is based upon the IEEE 802.16e mobile wireless standard. Coordinated efforts to develop appropriate aviation standards for the AeroMACS system are now underway within RTCA (United States) and Eurocae (Europe). AeroMACS will be implemented in a recently allocated frequency band, 5091-5150 MHz. As this band is also occupied by fixed satellite service uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference to the fixed satellite service are under analysis in order to enable the definition of standards that assure that such interference will be avoided. The NASA Glenn Research Center has been involved in this analysis, and the first results of modeling and simulation efforts directed at this analysis are the subject of this presentation.
    Keywords: Communications and Radar
    Type: E-17733V , 2011 IEEE Aerospace Conference; Mar 05, 2011 - Mar 12, 2011; Big Sky, MT; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 20
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    Using COMSOL Multiphysics Software to Model Anisotropic Dielectric and Metamaterial Effects in Folded-Waveguide Traveling-Wave Tube Slow-Wave Circuits (2008)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The electromagnetic effects of conventional dielectrics, anisotropic dielectrics, and metamaterials were modeled in a terahertz-frequency folded-waveguide slow-wave circuit. Results of attempts to utilize these materials to increase efficiency are presented.
    Keywords: Communications and Radar
    Type: NASA/TM-2008-215267 , P1.35 , E-16537 , Ninth International Vacuum Electronics Conference (IVEC 2008); Apr 22, 2008 - Apr 24, 2008; Monterey, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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