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  • 1
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    Ka-band MMIC array system for ACTS aeronautical terminal experiment (Aero-X) (1995)
    In:  CASI
    Details
    Publication Date: 2004-12-03
    Description: During the summer of 1994, the Advanced Communication Technology Satellite (ACTS) Aeronautical Terminal Experiment (Aero-X) was successfully completed by the NASA Lewis Research Center (LeRC) and the Jet Propulsion Laboratory (JPL). 4.8 and 9.6 Kbps duplex voice links were established between the LeRC Learjet and the ACTS Link Evaluation Terminal (LET) in Cleveland, Ohio, via the ACTS. The antenna system used in this demonstration was developed by LeRC and featured LeRC and US Air Force experimental arrays using GaAs MMIC devices at each radiating element for electronic beam steering and distributed power amplification. The antenna system consisted of three arrays mounted inside the LeRC Learjet, pointing out through the windows. An open loop tracking controller developed by LeRC used information from the aircraft position and attitude sensors to automatically steer the arrays toward ACTS during flight JPL ACTS Mobile Terminal (AMT) system hardware was used as transceivers both on the aircraft and at the LET. The single 32 element MMIC transmit array developed by NASA/LeRC and Texas Instruments has an EIRP of 23.4 dBW at boresight. The two 20 GHz MMIC receive arrays were developed in a cooperative effort with the USAF Rome Laboratory/Electronic System Center, taking advantage of existing USAF array development contracts with Boeing and Martin Marietta. The Boeing array has 23 elements and a G/T of 16/6 db/degK at boresight. The Martin Marietta array has 16 elements and a G/T of 16.1 db/degK at boresight. The three proof-of-concept arrays, the array control system and their integration and operation in the Learjet for Aero-X are described.
    Keywords: Communications and Radar
    Type: Proceedings of the Fourth International Mobile Satellite Conference (IMSC 1995); 312-317; NASA-CR-199955
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    The Effects of Ground Plane and Parasitic Layer on Linearly Tapered Slot Antenna (1996)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The effects of a large ground plane and an upper parasitic layer on a linearly tapered slot antenna has been experimentally investigated. Results indicate that the presence of a large ground plane causes the beam to steer by as much as 50 deg from the endfire direction in the H-plane. With the addition of a parasitic layer above the fed antenna, further beam scanning can be achieved when the spacing between the fed and parasitic layers is properly chosen.
    Keywords: Communications and Radar
    Type: NASA-TM-111721 , NAS 1.15:111721
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Phased-Array Antenna With Optoelectronic Control Circuits (1995)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Prototype phased-array antenna features control of amplitude and phase at each radiating element. Amplitude- and phase-control signals transmitted on optical fiber to optoelectronic interface circuit (OEIC), then to monolithic microwave integrated circuit (MMIC) at each element. Offers advantages of flexible, rapid electronic steering and shaping of beams. Furthermore, greater number of elements, less overall performance of antenna degraded by malfunction in single element.
    Keywords: ELECTRONIC COMPONENTS AND CIRCUITS
    Type: LEW-15391 , Laser Tech. Brief.; 1; P. 86
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    Conformal, Transparent Printed Antenna Developed for Communication and Navigation Systems (1999)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: Conformal, transparent printed antennas have advantages over conventional antennas in terms of space reuse and aesthetics. Because of their compactness and thin profile, these antennas can be mounted on video displays for efficient integration in communication systems such as palmtop computers, digital telephones, and flat-panel television displays. As an array of multiple elements, the antenna subsystem may save weight by reusing space (via vertical stacking) on photovoltaic arrays or on Earth-facing sensors. Also, the antenna could go unnoticed on automobile windshields or building windows, enabling satellite uplinks and downlinks or other emerging high-frequency communications.
    Keywords: Communications and Radar
    Type: Research and Technology 1998; NASA/TM-1999-208815
    Format: application/pdf
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  • 5
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    Feasibility Study of Optically Transparent Microstrip Patch Antenna (1997)
    In:  Other Sources
    Details
    Publication Date: 2018-06-02
    Description: The paper presents a feasibility study on optically transparent patch antennas with microstrip line and probe feeds. The two antennas operate at 2.3 GHz and 19.5 GHz respectively. They are constructed from a thin sheet of clear polyester with an AgHT-8 optically transparent conductive coating. The experimental results show good radiation patterns and input impedance match. The antennas have potential applications in mobile wireless communications.
    Keywords: Communications and Radar
    Type: IEEE Antennas and Propagation Society International Symposium 1997. Volume 4: Digest; 2100-2103; IEEE-Catalog-97CH36122-Vol-4
    Format: text
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  • 6
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    Orthogonal feeding techniques for tapered slot antennas (1998)
    In:  Other Sources
    Details
    Publication Date: 2018-06-05
    Description: For array of "brick" configuration there are electrical and mechanical advantages to feed the antenna with a feed on a substrate perpendicular to the antenna substrate. Different techniques have been proposed for exciting patch antennas using such a feed structure.Rncently, an aperture-coupled dielectric resonator antenna using a perpendicular feed substrate has been demonstrated to have very good power coupling efficiency. For a two-dimensional rectangular array with tapered slot antenna elements, a power combining network on perpendicular substrate is generally required to couple power to or from the array. In this paper, we will describe two aperture-coupled techniques for coupling microwave power from a linearly tapered slot antenna (LTSA) to a microstrip feed on a perpendicular substrate. In addition, we will present measured results for return losses and radiation patterns.
    Keywords: Communications and Radar
    Type: IEEE Antennas and Propagation Society International Symposium 1998 Digest. Antennas: Gateways to the Global Network, Volume 2; 1172-1175; IEEE-Catalog-98CH36194-Vol-2
    Format: text
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    NASA TECHNICAL REPORTS
  • 7
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    Multibeam Phased-Array Antennas Developed and Characterized (2003)
    In:  CASI
    Details
    Publication Date: 2018-06-05
    Description: Fixed-formation microsatellites have been proposed for future NASA missions to lower costs and improve data collection and reliability. Achieving seamless connectivity communications between these satellites requires the use of multibeam array antennas. As a result of NASA Glenn Research Center s collaborative efforts with the University of Colorado and Texas A&M University, two prototype multibeam array antennas have been developed and demonstrated at Ka-band frequencies. These arrays are designed to be dual-beam, dual-frequency arrays, with two fixed scan beams at around +/- 30 . They can be used in both ground and space systems for transmit and receive functions.
    Keywords: Communications and Radar
    Type: Research and Technology 2002; NASA/TM-2003-211990
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 8
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    A Spherical to Plane Wave Transformation Using a Reflectarray (1997)
    In:  Other Sources
    Details
    Publication Date: 2018-06-05
    Description: A reflectarray has generally been used as a replacement for a reflector antenna. Using in this capacity, different configurations (prime focus, offset etc.) and various applications (dual frequency, scanning etc.) have been demonstrated with great success. Another potential application that has not been explored previously is the use of reflectarrays to compensate for phase errors in space power combining applications such as space-fed lens and power combining amplifier. In these applications, it is required to convert a spherical wave to a plane wave with proper phase correction added to each element of the reflectarray. This paper reports an experiment to investigate the feasibility of using a reflectarray as an alternative to a lens in space power combining. The experiment involves transforming a spherical wave from a orthomode horn to a plane wave at the horn aperture. The reflcctarray consists of square patches terminated in open stubs to provide necessary phase compensation. In this paper, preliminary results will be presented and the feasibility of such compensation scheme will be discussed.
    Keywords: Communications and Radar
    Type: IEEE Antennas and Propagation Society International Symposium 1997. Volume 2: Digest; 1284-1287; IEEE-Catalog-97CH36122-Vol-2
    Format: text
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    NASA TECHNICAL REPORTS
  • 9
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    Small X-Band Oscillator Antennas (2009)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A small, segmented microstrip patch antenna integrated with an X-band feedback oscillator on a high-permittivity substrate has been built and tested. This oscillator antenna is a prototype for demonstrating the feasibility of such devices as compact, low-power-consumption building blocks of advanced, lightweight, phased antenna arrays that would generate steerable beams for communication and remotesensing applications.
    Keywords: Communications and Radar
    Type: LEW-18114-1 , NASA Tech Briefs, November 2009; 11-12
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 10
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    Notch Antennas (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: Notch antennas, also known as the tapered slot antenna (TSA), have been the topics of research for decades. TSA has demonstrated multi-octave bandwidth, moderate gain (7 to 10 dB), and symmetric E- and H- plane beam patterns and can be used for many different applications. This chapter summarizes the research activities on notch antennas over the past decade with emphasis on their most recent advances and applications. This chapter begins with some discussions on the designs of single TSA; then follows with detailed discussions of issues associated with TSA designs and performance characteristics. To conclude the chapter, some recent developments in TSA arrays and their applications are highlighted.
    Keywords: Communications and Radar
    Type: NASA/TM-2004-213057 , E-14503
    Format: application/pdf
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