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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Millimeter-wave pseudomorphic HEMT MMIC phased array components for space communications

Recent advances in pseudomorphic HEMT MMIC (PMHEMT/MMIC) technology have made it the preferred candidate for high performance millimeter-wave components for phased array applications. This paper describes the development of PMHEMT/MMIC components at Ka-band and V-band. Specifically, the following PMHEMT/MMIC components will be described: power amplifiers at Ka-band; power amplifiers at V-band; and four-bit phase shifters at V-band. For the Ka-band amplifier, 125 mW output power with 5.5 dB gain and 21 percent power added efficiency at 2 dB compression point has been achieved. For the V-band amplifier, 112 mW output power with 6 dB gain and 26 percent power added efficiency has been achieved. And, for the V-band phase shifter, four-bit (45 deg steps) phase shifters with less than 8 dB insertion loss from 61 GHz to 63 GHz will be described.

Lan, G. L.↗
NASA NTRS1991

High efficiency Ka-band MMIC amplifiers

This paper describes recent progress in the Ka-band MMIC power amplifier program. New materials, material growth techniques, device designs and circuit design techniques have made it possible to design and fabricate MMIC amplifiers with both high efficiency and high power at Ka-band and higher frequencies. MMIC amplifiers using pseudomorphic AlGaAs/InGaAs/GaAs HEMT devices presently achieve 400 mW with 25 percent efficiency at Ka-band and 1 W, 35 percent efficient amplifiers are being developed.

Haugland, Edward J.↗
NASA NTRS1988

Ka-band MMIC beam steered transmitter array

A 32 GHz six element linear transmitter array which employs MMIC phase shifters and power amplifiers is developed and its performance is evaluated. The MMIC phase shifters contains 14 MESFETs in three digital switched line and one analog loaded line phase shifter, and the MMIC power amplifiers are two stage amplifiers using GaAs MESFETs with 0.25 micron gate lengths and gate widths of 0.1 mm and 0.3 mm. The design of the array is described. The phase shift measurements for the MMIC devices are analyzed. The data reveal that the switched line phase shifters are accurate to within 7 pct; the power amplifier 1 dB compressed output power varied over 0.3 dB; the beamwidth of the array is 7.5 deg; and beam steering is over + or - 8 deg.

Riley, A. L.↗
NASA NTRS1989

Telecommunications technology development for the Deep Space Network

The telecommunications technology that is currently being developed for the Deep Space Network (DSN), a system providing communications and navigation support for NASA's deep space missions, is discussed. The major areas of development include Ka-band (32 GHz) technology, beam waveguide antennas, low-noise amplifiers, coding, navigation techniques, high-power transmitters, and optical technology. The expected payoffs of the new technology during the mid-1990's and later are examined.

Yuen, J. H.↗
NASA NTRS1989

Ka-band MMIC beam steered transmitter array

A 32-GHz six-element linear transmitter array utilizing monolithic microwave integrated circuit (MMIC) phase shifters and power amplifiers was designed and tested as part of the development of a spacecraft array feed for NASA deep-space communications applications. Measurements of the performance of individual phase shifters, power amplifiers, and microstrip radiators were carried out, and electronic beam steering of the linear array was demonstrated. The switched-line phase shifters were accurate to within 7 percent on average and the power amplifier 1-dB compressed output power varied over 0.3 dB. The array had a beamwidth of 7.5 deg and demonstrated acceptable beam steering over + or - 8 deg. From the results, it can be concluded that this MMIC phased array has adequate beam-scanning capability for use in the two-dimensional array. The areas that need to be improved are the efficiency of the MMIC power amplifier and the insertion loss of the MMIC phase shifter.

Rascoe, D. L.↗
NASA NTRS1992

Ka-band active MMIC subarray development

A 4 x 8 array consisting of two adjacent 4 x 4 MMIC subarray modules under development as part of a MMIC insertion program for the ACTS communication experiments is presented. The subarray features a high-density 'tile' configuration integrating 16 MMIC power amplifiers and 16 MMIC phase shifters. The radiating elements are cavity-backed, aperture coupled, linearly polarized microstrip patches arranged on a 4 x 4 square grid. Each module also incorporates a MMIC controller to set the phase shifts and to turn individual amplifiers 'on' or 'off'. The novel module construction technique is expected to establish a benchmark in Ka-band and higher-frequency array architectures. The hybrid integration approach used for the module can be replaced by multifunctional chips and multilayer distribution boards. The higher level of integration is to permit the dense grid spacing required for wide-angle scanning and reduced size, weight, and cost for the array.

Lee, Richard↗
NASA NTRS1990

NASA developments in solid state power amplifiers

Over the last ten years, NASA has undertaken an extensive program aimed at development of solid state power amplifiers for space applications. Historically, the program may be divided into three phases. The first efforts were carried out in support of the advanced communications technology satellite (ACTS) program, which is developing an experimental version of a Ka-band commercial communications system. These first amplifiers attempted to use hybrid technology. The second phase was still targeted at ACTS frequencies, but concentrated on monolithic implementations, while the current, third phase, is a monolithic effort that focusses on frequencies appropriate for other NASA programs and stresses amplifier efficiency. The topics covered include: (1) 20 GHz hybrid amplifiers; (2) 20 GHz monolithic MESFET power amplifiers; (3) Texas Instruments' (TI) 20 GHz variable power amplifier; (4) TI 20 GHz high power amplifier; (5) high efficiency monolithic power amplifiers; (6) GHz high efficiency variable power amplifier; (7) TI 32 GHz monolithic power amplifier performance; (8) design goals for Hughes' 32 GHz variable power amplifier; and (9) performance goals for Hughes' pseudomorphic 60 GHz power amplifier.

Leonard, Regis F.↗
NASA NTRS1992

Proposed Solar Probe telecommunications system concept

A proposed telecommunications system concept for NASA's Solar Probe mission is described. Key system requirements include 70 kbps data rate at perihelion and operation at X-band (uplink/downlink) and Ka-band (downlink). A design control table is presented to demonstrate design compliance with telecommunication needs. The Ka-band feed is to be a hexagonal array of 37 active elements, each containing 1/4W HEMT amplifiers. The array is located at the Cassegrain point of a 0.75-m reflector. When compared to the TWTA-based system, the Ka-band active array feed provides advantages of reduced mass, increased dc power efficiency, enhanced reliability, graceful degradation, and reduced volume requirements.

Kellogg, K.↗
NASA NTRS1992

The ACTS multibeam antenna

The Advanced Communications Technology Satellite (ACTS) to be launched in 1993 introduces several new technologies including a multibeam antenna (MBA) operating at Ka-band. The satellite is introduced briefly, and then the MBA, consisting of electrically similar 30 GHz received and 20 GHz transmit offset Cassegrain systems utilizing orthogonal linear polarizations, is described. Dual polarization is achieved by using one feed assembly for each polarization in conjunction with nested front and back subreflectors, the gridded front subreflector acting as a window for one polarization and a reflector for the other. The antennas produce spot beams with approximately 0.3 deg beamwidth and gains of approximately 50 dbi. High surface accuracy and high edge taper produce low sidelobe levels and high cross-polarization isolation. A brief description is given of several Ka-band components fabricated for ACTS. These include multiflare antenna feedhorns, beam-forming networks utilizing latching ferrite waveguide switches, a 30 GHz high mobility electron transmitter (HEMT) low-noise amplifier and a 20 GHz TWT power amplifier.

Regier, Frank A.↗
NASA NTRS1992

Proposed Ka-band array-fed near field Cassegrain system for NASA's Polar Probe Mission

A Ka-band array-fed near-field Cassegrain antenna envisioned for NASA's Solar Probe Mission is the basis of the present spacecraft telecommunications system, which is designed for operation at X-band up/downlink and Ka-band downlink. The hexagonal array employed, which is located at the Cassegrain point of the 0.75-m reflector, encompasses 37 active elements; each of these contains 1/4-W HEMT amplifiers. Relative to a TWTA-based system, this active array feed reduces mass, increases dc power efficiency, enhanced reliability, and reduces volume requirements.

Kellogg, K.↗
NASA NTRS1985

High power Ka-band transmitter for planetary radar and spacecraft uplink

A proposed conceptual design of a 400 kW CW Ka-Band transmitter and associated microwave components to be used for planetary radar and serve as a prototype for feature spacecraft uplinks is discussed. System requirements for such a transmitter are presented. Performance of the proposed high power millimeter wave tube, the gyroklystron, is discussed. Parameters of the proposed power amplifier, beam supply, and monitor and control devices are also presented, Microwave transmission line components consisting of signal monitoring devices, signal filtering devices, and an overmoded corrugated feed are discussed. Finally, an assessment of the state of the art technology to meet the system requirements is given and possible areas of difficulty are summarized.

Bhanji, A.M.↗
NASA NTRS1986

Conceptual design of high power Ka-band radar transmitter

A proposed conceptual design of a 400-kW CW Ka-band transmitter and associated microwave components to be used for planetary radar and serve as a prototype for future spacecraft uplinks is discussed. System requirements for such a transmitter are presented. Performance of the proposed high-power millimeter-wave tube, the gyroklystron, is discussed. Parameters of the proposed power amplifier, beam supply, and monitor and control devices are also presented. Microwave transmission-line components consisting of signal-monitoring devices, mode converter, and an overmoded corrugated feed are discussed. Finally, an assessment of the state-of-the-art technology to meet the system requirements is given, and possible areas of difficulty are summarized.

Bhanji, Alaudin↗
NASA NTRS1981

The 30/20 GHz demonstration system SSUS-D/BSE

The systems consisting of a 30/20 GHz communication satellite featuring a multiple fixed beam and scanning beam antenna, SS-TDMA, onboard processing and high power TWT's and IMPATT amplifiers, a trunking space-diversity Earth station, a customer premise system (CPS) portable Earth station and a Master Control Station. Hardware, software and personnel are included to build and launch one satellite and to carry on a two year experimentation and demonstration period of advanced Ka-band systems concepts and technology. Included are first level plans identifying all tasks, a schedule for system development and an assessment of critical technology and risk and a preliminary experiments plan.

Source record↗
NASA NTRS1987

An advanced geostationary communications platform

A large geostationary communications platform can offer many attractive possibilities for providing lower cost communications. The platform payload concept described in this paper attempts to exploit these possibilities. The use of a combination of spot and wide-area coverage beams accommodates users in both high- and low-density population areas, and provides a good degree of frequency reuse. A standard channel bandwidth, used for most traffic, facilitates interconnectivity among C-, Ku-, and Ka-band users who may all access the platform. Adoption of a 36-MHz channel bandwidth leads to transmission rates that would be easily handled by low-cost terminals providing direct customer premises service. This also lends itself well to a solution using a large number of solid-state power amplifiers operating in all three frequency bands and sharing a common, redundant, conditioned power supply.

Hawkes, Thaddeus A.↗
NASA NTRS1991

A high efficiency Ka-band monolithic pseudomorphic HEMT amplifier

A monolithic three-stage Ka-band amplifier has been designed and fabricated on a doped channel heterostructure. Devices with gate length of 0.2 micron and gate width of 50, 100, and 250 micron were cascaded. The gate and drain bias networks were also integrated. The small signal gain is 31 dB and the amplifier is capable of an output power of 190 mW with 23 dB gain and 30.2 percent power added efficiency at 31 GHz. This is a record efficiency for a multistage MMIC at this frequency.

Saunier, Paul↗
NASA NTRS1991

Monolithic microwave integrated circuits for sensors, radar, and communications systems; Proceedings of the Meeting, Orlando, FL, Apr. 2-4, 1991

Consideration is given to MMICs for airborne phased arrays, monolithic GaAs integrated circuit millimeter wave imaging sensors, accurate design of multiport low-noise MMICs up to 20 GHz, an ultralinear low-noise amplifier technology for space communications, variable-gain MMIC module for space applications, a high-efficiency dual-band power amplifier for radar applications, a high-density circuit approach for low-cost MMIC circuits, coplanar SIMMWIC circuits, recent advances in monolithic phased arrays, and system-level integrated circuit development for phased-array antenna applications. Consideration is also given to performance enhancement in future communications satellites with MMIC technology insertion, application of Ka-band MMIC technology for an Orbiter/ACTS communications experiment, a space-based millimeter wave debris tracking radar, low-noise high-yield octave-band feedback amplifiers to 20 GHz, quasi-optical MESFET VCOs, and a high-dynamic-range mixer using novel balun structure.

Leonard, Regis F.↗
NASA NTRS1991

A personal communications network using a Ka-band satellite

The feasibility of portable communications terminals that can provide 4.8-kbps voice communications to a hub station via a Ka-band geosynchronous satellite was investigated. Tradeoffs are examined so that the combined system of the hub and gateway earth stations, the satellite, and the personal terminals can provide a competitive service in terms of cost, availability, and quality. A baseline system is described using a spacecraft with approximately 140 spot beams that cover CONUS with 5-watt power amplifiers in each beam. Satellite access in both the forward and return directions uses Frequency Division Multiple Access/Code Division Multiple Access (FDMA/CDMA) with a chip rate of 2.5 Mchip/sec. An experiment is recommended using the Advanced Communications Technology Satellite (ACTS) to demonstrate some of the features of the portable terminal concept.

Palmer, L. C.↗
NASA NTRS1992

A personal communications network using a Ka-band satellite

The feasibility of a personal communications network using portable terminals that can provide 4.8-kb/s voice communications to a hub station via a Ka-band geosynchronous satellite has been investigated. Tradeoffs are examined so that the combined system of hub and gateway earth stations, the satellite, and the personal terminals can provide a competitive service in terms of cost, availability, and quality. A baseline system that uses a spacecraft with approximately 140 spot beams to cover the contiguous US (CONUS) and 5-W power amplifiers in each beam is described. Satellite access in both the forward and return directions uses frequency-division multiple-access/code-division multiple-access (FDMA/CDMA) with a chip rate of 2.5 Mchip/s.

Palmer, Larry C.↗