Showing papers on "Ka band published in 1992"
TL;DR: The implemented flexible, processor based, TDMA station, together with the good performance of Olympus, shows that the Ka band is usable for the mentioned types of networks without prohibitive fade degradation, at least for limited coverages.
Abstract: Summary A flexible, processor based, TDMA station has been implemented. This station and its associated variable data rate modem enables users to implement very complex frame structures under software control. Burst rates of 512 Kbit/s - 8.192 Mbit/s and different coding rates are possible allowing the transmitted bit energy from each station in the network to be adapted to prevailing conditions. The proposed application of the station is the transmission of mixed stream and packet traffic, in a LANs interconnection v ia satellite e nvironment, using a modification o f the FODA 5 technique. The association o f the up-link po wer control feature with the bit and coding rate variation g ives the system an interesting ability to cope with fade conditions. The link outage probability is investigated for the Olympus transponder in Ka band. The a bility o f the system, together with the good performance of Olympus, shows that t he Ka band is usable for the a bove mentioned types of networks without prohibitive fade degradation, at least for limited coverages.
34 citations
18 Jun 1992
TL;DR: In this article, a frequency-selective subreflector (FSS) design for the CRAF/Cassini (C/C) project is presented, which allows a Cassegrain configuration at X (7.2 and 8.4 GHz), and a prime focus configuration at S (2.3 GHz) and Ku (13.8 GHz) bands.
Abstract: NASA's CRAF/Cassini (C/C) project requires the use of multiple RF frequencies at S, X, Ku, and Ka bands for science investigations and data communications links. A single high-gain antenna (HGA) will be used. It incorporates a frequency-selective subreflector (FSS) to allow a Cassegrain configuration at X (7.2 and 8.4 GHz) and Ka (32 and 34.5 GHz) bands, and a prime focus configuration at S (2.3 GHz) and Ku (13.8 GHz) bands. A four-based FSS design for the C/C application is reported. The selection of the concentric ring elements is based on the fact that the ring's geometry is particularly conformable to the present circular polarization requirement and ease of manufacture. >
29 citations
NEC1
TL;DR: In this article, a 1/16 frequency divider was implemented with a silicon bipolar technology with a cutoff frequency of 40 GHz, covering the Ka band (18-26.5 GHz).
Abstract: A dynamic frequency divider applying the regenerative frequency division principle has been developed. A spiral inductor on the silicon substrate used as a load is characterized, and an improved one-port model with the substrate resistance is discussed. A 1/16 frequency divider was implemented with a silicon bipolar technology with a cutoff frequency of 40 GHz. The operation frequency range was 11.8-28.1 GHz, covering the Ka band (18-26.5 GHz). The inductive load has improved the maximum operation frequency by 7%, compared with a conventional circuit. Complemented with a 21-GHz static frequency divider previously reported by the authors, the whole microwave frequency range up to 26.5 GHz has been completely covered with the silicon bipolar technology. The maximum operation frequency of a silicon MMIC has been extended to the millimeter-wave frequency region for the first time. >
22 citations
01 Jun 1992
TL;DR: In this paper, the design and performance of high-efficiency, broadband (up to 7 GHz), monolithic Ka-band amplifiers using doped channel power pseudomorphic high-electron-mobility transistors (HEMTs) are discussed.
Abstract: The design and performance of high-efficiency, broadband (up to 7 GHz), monolithic Ka-band amplifiers using doped channel power pseudomorphic high-electron-mobility transistors (HEMTs) are discussed. Amplifiers with output powers as high as 500 mW and power-added-efficiencies as high as 40% were demonstrated. >
16 citations
TL;DR: The feasibility of a personal communications network using portable terminals that can provide 4.8 kb/s voice communications to a hub station via Ka-band geosynchronous satellite has been investigated and tradeoffs are examined.
Abstract: The feasibility of a personal communications network using portable terminals that can provide 4.8 kb/s voice communications to a hub station via 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. >
13 citations
01 Aug 1992
TL;DR: In this paper, the performance of gold and superconducting Ka-band microstrip antennas at various temperatures was evaluated using a closed cycle gas-cooled refrigerator in a far field range.
Abstract: The measurement of cryogenic antennas poses unique logistical problems since the antenna under test must be embedded in the cooling chamber. A method for measuring the performance of cryogenic microstrip antennas using a closed cycle gas-cooled refrigerator in a far field range is described. Antenna patterns showing the performance of gold and superconducting Ka-band microstrip antennas at various temperatures are presented.
11 citations
TL;DR: In this article, an MMIC transmitter for high-volume smart munition applications in the Ka band is developed using 0.25 mu m MESFET technology, consisting of a voltage-controlled oscillator (VCO) and power amplifier (PA).
Abstract: An MMIC transmitter for high-volume smart munition applications in Ka band is developed using 0.25 mu m MESFET technology. The transmitter, consisting of a voltage-controlled oscillator (VCO) and power amplifier (PA), delivers more than 100 mW of power with an overall efficiency of 10% and a linear tuning range of more than 700 MHz around 35 GHz. >
8 citations
6 citations
29 Sep 1992
TL;DR: In this article, the limitations of a class of earth terminals, including handheld units, operating at the Ka-band are explored, and it is shown that satellite handheld communicators are feasible if certain operating constraints are accepted.
Abstract: Personal communications will be supported in metropolitan areas using terrestrial-based transmission means and the L-band portion of the frequency spectrum. On the other hand, satellite communications' global coverage makes it attractive to provide service to remote areas. The Ka-band offers several advantages to support such services, notably the abundance of available spectrum. The limitations of a class of earth terminals, including handheld units, operating at Ka-band are explored. These limitations include service availability (effect of rain), radiation hazards, call notification and antenna pointing. It is shown that satellite handheld communicators are feasible if certain operating constraints are accepted. Finally the characteristics of the satellite and the multiple access techniques suitable for providing this service are described. >
6 citations
11 Aug 1992
TL;DR: In this paper, an SS-TDMA transponder equipped with a large-scale, dynamic satellite switch and a highly flexible and efficient high-power mobile communications transPonder have been developed.
Abstract: An SS-TDMA transponder equipped with a large-scale, dynamic satellite switch, and a highly flexible and efficient high power mobile communications transponder have been developed. Utilizing these multibeam transponders is one of the most promising approaches for enhancing transmission capacity and economization, and for facilitating improvements in the mass, size and DC power efficiency of the system.
4 citations
04 Oct 1992
TL;DR: In this paper, two Ka-band amplifiers in coplanar waveguide (CPW) technology are presented, one based on 0.3-mu m MESFETs and the other based on a 0.25- mu m high-electron-mobility transistors.
Abstract: Two Ka-band amplifiers in coplanar waveguide (CPW) technology are presented. The four-stage design is based on 0.3- mu m MESFETs, whereas in the three-stage amplifier 0.25- mu m high-electron-mobility transistors (HEMTs) are used. The monolithic microwave integrated circuits (MMICs) are designed for a gain of 20 dB. The authors present the realized MMICs and in particular the way in which typical difficulties arising from transforming theoretical demands into a coplanar circuit layout can be overcome. The applicability and accuracy of the developed design procedures are demonstrated by comparison of simulated and measured results. >
06 Dec 1992
TL;DR: A concept for a future advanced mobile satellite communications system using a geostationary satellite is described in this article, where a multiple spotbeam antenna, onboard beam interconnection, and millimeter-wave and Ka-band components are required.
Abstract: A concept for a future advanced mobile satellite communications system using a geostationary satellite is described. In the satellite of this system, a multiple spotbeam antenna, onboard beam interconnection, and millimeter-wave and Ka-band components are required. The configuration of the payloads of Japan's COMETS (Communications and Broadcasting Engineering Test Satellite) for advanced mobile satellite communication experiments is also described. The transponder has an IF filter bank and a SCPC/TDM (signal-carrier-per-channel/time-dimension multiplexing) regenerative modem for beam interconnection. >
TL;DR: In this article, a single-ended three-stage MESFET power amplifier designed for high-volume, low-cost applications shows an average of 15-21% power added efficiency in Ka-band with 100-150 mW of power output over 30-35 GHz.
Abstract: A single-ended three-stage MESFET power amplifier designed for high-volume, low-cost applications shows an average of 15-21% power added efficiency in Ka-band with 100-150 mW of power output over 30-35 GHz. Delta >
01 Jan 1992
TL;DR: In this article, a Ka-band array-fed near-field Cassegrain antenna was used for NASA's Solar Probe Mission (SPM) communications system, which was designed for operation at X-band up/downlink and K-band downlink.
Abstract: 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.
15 May 1992
TL;DR: In this article, the design and breadboard of an active transmitting array at Ka-band frequencies and its application to a reflector antenna system is described, where the array is intended as a feed array in a near-field Cassegrain or Gregorian dual-reflector antenna systems.
Abstract: The design and breadboard of an active transmitting array at Ka-band frequencies and its application to a reflector antenna system is described. The array is intended as a feed array in a near-field Cassegrain or Gregorian dual-reflector antenna system. It uses tapered slot (Vivaldi) elements in a break architecture. The array has been tested for RF performance. Its performance is acceptable, but there are some areas where improvements in the performance are possible. It was found that particular attention must be paid to the losses at the input to the array elements and in the element itself. Variation of the array phase center in different azimuth planes is another area of concern. The Vivaldi elements have a linear polarization and do not lend themselves easily to a circularly polarized arrangement. For lower losses and circular polarization, microstrip patch arrays in a tile configuration were found to be more advantageous. >
TL;DR: In this paper, the design, fabrication, and performance of a Ka-band, two-stage, low-noise hybrid amplifier (LNA) is discussed, and the LNA's extremely wide-band measured performance is state of the art with a gain exceeding 10 dB from 14 to 37 GHz and a noise figure less than 3 dB from at least 27 to 38 GHz.
Abstract: The design, fabrication, and performance of a Ka-band, two-stage, low-noise hybrid amplifier (LNA) are discussed. The LNA's extremely wide-band measured performance is state of the art with a gain exceeding 10 dB from 14 to 37 GHz and a noise figure less than 3 dB from at least 27 to 37 GHz.
01 Jun 1992
TL;DR: In this paper, integrated circuit (IC) modules have been developed for a multichannel Ka-band receiver, which includes a monolithic microwave integrated circuit compatible mixer/IF amplifier and a MIC local oscillator (LO) distribution network.
Abstract: Integrated circuit (IC) modules have been developed for a multichannel Ka-band receiver. The modules include a monolithic microwave integrated circuit (MMIC)-compatible mixer/IF amplifier and a microwave integrated circuit (MIC) local oscillator (LO) distribution network. Four mixer/IF modules have been integrated with the LO network and other components to form a multichannel receiver prototype. Measurements of the receiver confirmed that the system objectives have been achieved. The system showed high sensitivity, wide dynamic range, and the ability to accurately measure the relative amplitude among channels. By using MMIC-compatible front-end components in key locations, the feasibility of low-cost production has been demonstrated. >
01 Aug 1992
TL;DR: In this article, an antenna system consisting of three experimental Ka-band active arrays using GaAs MMIC devices at each radiating element for electronic beam steering and distributed power amplification is presented.
Abstract: An antenna system consisting of three experimental Ka-band active arrays using GaAs MMIC devices at each radiating element for electronic beam steering and distributed power amplification is presented. The MMIC arrays are to be demonstrated in the ACTS Aeronautical Terminal Experiment, planned for early 1994. The experiment is outlined, with emphasis on a description of the antenna system. Attention is given to the way in which proof-of-concept MMIC arrays featuring three different state-of-the-art approaches to Ka-band MMIC insertion are being incorporated into an experimental aircraft terminal for the demonstration of an aircraft-to-satellite link, providing a basis for follow-on MMIC array development.
25 Jun 1992
TL;DR: 12 different hybrid satellite-terrestrial network configurations developed and tested using Telesat's Ku-band Anik C/E satellites are presented and the results of these experiments are discussed.
Abstract: The integration of local wireless radio (e.g. cordless technology) with satellite networks is expected to provide a practical, economic solution for the provision of wide area personal communication services in a reasonable timeframe. The authors have considered and analysed a number of alternative hybrid (terrestrial+satellite) network architectures for evolving viable option(s). The paper briefly presents 12 different hybrid satellite-terrestrial network configurations developed and tested using Telesat's Ku-band Anik C/E satellites. The tests were repeated using European Olympus Ka-band satellite. The results of these experiments are discussed. >
01 Aug 1992
TL;DR: In this article, the design and development of a small, optically controlled phased array antenna suitable for communication satellite applications are discussed, which minimizes the size of the array with its associated beamforming network (BFN).
Abstract: The design and development of a small, optically controlled phased array antenna suitable for communication satellite applications are discussed. A vertical integration architecture is used which minimizes the size of the array with its associated beamforming network (BFN). The antenna features a four-element linear microstrip array that uses aperture coupling of the antenna elements to the BFN; a modified Wilkinson power divider BFN; and 32 GHz, four-bit monolithic microwave integrated circuit (MMIC) phase shifters in customized quartz packages with corresponding optoelectronic interface circuits (OEIC's) for control signal reception.
01 Jan 1992
TL;DR: In this article, the authors developed a new class of Ka-band TWT amplifiers (TWTAs) which achieved their high efficiency/low power performance goals by means of an advanced dynamic velocity taper (DVT).
Abstract: NASA has developed a new class of Ka-band TWT amplifiers (TWTAs) which achieve their high efficiency/low power performance goals by means of an advanced dynamic velocity taper (DVT). The DVT is characterized by a continuous, nonlinear reduction in helix pitch from its initial synchronous value in the output section of the TWT to near the end of the helix. Another efficiency-maximizing feature is the inclusion of a multistage depressed collector employing oxygen-free, high-conductivity Cu electrodes treated for secondary electron emission suppression by means of ion bombardment. An efficiency of 43 percent is expected to be reached.
TL;DR: In this paper, a Ka-band monolithic HEMT power amplifier, based on 0.25- mu m gatelength single quantum-well AlGaAs-InGaAs pseudomorphic high-electron mobility transistor (PM-HEMT) technology, has been developed for millimeter-wave system applications.
Abstract: A Ka-band monolithic HEMT power amplifier, based on 0.25- mu m gatelength single quantum-well AlGaAs-InGaAs pseudomorphic high-electron mobility transistor (PM-HEMT) technology, has been developed for millimeter-wave system applications. These amplifiers include single-ended and on-chip combined configurations and have on-chip DC-block, RF-bypass and bias network. A cascaded four-stage power amplifier exhibited 210 mW output power with an associated gain of 21.3 dB at 34.5 GHz. The saturated output power of this amplifier exceeded 230 mW. These power modules need only single positive bias to simplify system power supply requirements, and are highly stable. Moreover, multistages can easily be cascaded/combined to achieve even higher gain and power for future millimeter-wave systems. >
01 Jun 1992
TL;DR: In this article, the authors investigated monostatic and bistatic polarization and electromagnetic phenomenology at various low and high frequencies such as L, X and Ka bands for the purpose of enhancing the performance of synthetic aperture ground imaging radars for automatic target detection/classification.
Abstract: : This is the final report on Contract No. F33615-88-C-1792 for Wright-Patterson Air Force Base over the period August 1988 through May 1991. The overall goals and accomplishments are summarized. The goal of this contract is the investigation of monostatic and bistatic polarization and electromagnetic phenomenology at various low and high frequencies such as L, X and Ka bands for the purpose of enhancing the performance of synthetic aperture ground imaging radars for automatic target detection/classification. This is accomplished via measurements and analytic modeling of simple scatterers and complex targets comprising an ensemble of simple scatterers. Specific radar scattering data are obtained in the frequency range 2-18 GHz on scale model targets and at frequencies below 2 GHz for full size targets. In both cases, coherent magnitude and phase signal versus target orientation, frequency and polarization are collected.
25 Jun 1992
TL;DR: Ka-band offers several advantages to support personal communications using terrestrial-based transmission means and the L-band portion of the frequency spectrum, notably the abundant spectrum space available.
Abstract: Personal communications will be supported in metropolitan areas using terrestrial-based transmission means and the L-band portion of the frequency spectrum. On the other hand, satellite communications' global coverage makes it attractive to provide service to remote areas. Ka-band offers several advantages to support such services, notably the abundant spectrum space available. The service concept gives rise to a number of systems issues which are analyzed. It is shown that service availability, radiation hazards, and long and short term frequency stability severely limit the possible approaches to system design. >
TL;DR: In this paper, a monolithic Ka-band transmitter consisting of a voltage-controlled oscillator (VCO) and a power amplifier using 0.25 mu m MESFET technology has been developed for high volume production.
Abstract: A monolithic Ka-band transmitter consisting of a voltage-controlled oscillator (VCO) and a power amplifier using 0.25 mu m MESFET technology has been developed for high volume production. An output power of 21.5 dBm at 35.4 GHz with a tuning range of 600 MHz has been achieved. Hundreds of these monolithic transmitters have been fabricated, and an RF yield of 40% has ben achieved from the GaAs MMIC pilot line based on the total number of wafers started. The high yield obtained from this high level integration of multifunctional MMIC chips indicates the maturity of the design and processing capability of millimeter-wave (MMW) GaAs MESFET technology. >
01 Jan 1992
TL;DR: In this article, the authors describe the development of a 4x4 microstrip array which will be used as a feed for a low cost ACTS ground terminal, which is fed with coplanar waveguide power dividing networks.
Abstract: Because of low cost and ease of fabrication, microstrip arrays are attractive as feeds for reflector antenna systems. This paper describes the development of a 4x4 microstrip array which will be used as a feed for a low cost ACTS ground terminal. The array feed consisting of four 2x2 subarrays is fed with coplanar waveguide power dividing networks. The patch radiator is designed to excite two orthogonal, linearly polarized waves at Ka-band frequencies (around 20 and 30 GHz). Test results for the developed array are presented.