Showing papers on "Ka band published in 1990"
TL;DR: In this article, a gyrotron backward-wave oscillator was operated and magnetically tuned over the frequency range 27-32 GHz and the output power was as large as 7 kW, corresponding to a device efficiency of 19%.
Abstract: A gyrotron backward-wave oscillator (gyro-BWO) has been operated and magnetically tuned over the frequency range 27-32 GHz. Tuning by varying the electron beam voltage was effective over a smaller frequency range ( Delta f approximately 1 GHz). Output power was as large as 7 kW, corresponding to a device efficiency of 19%. This large efficiency value was unexpected, and related analysis indicates it may be associated with the nonuniform magnetic field profile in the interaction region. >
93 citations
08 May 1990
TL;DR: In this paper, a 32 GHz, 21-element array feed incorporating 63 MMIC (monolithic microwave integrated circuit) devices and providing electronic beam steering using 21 VLSI control chips is presented.
Abstract: A 32-GHz, 21-element array feed incorporating 63 MMIC (monolithic microwave integrated circuit) devices and providing electronic beam steering using 21 VLSI control chips is under development. An innovative building-block construction approach providing easy verification of device performance prior to integration in the array is described. In addition, the subarray layer concept with plug-in RF connectors allows for easy removal of a layer for repairing one of the components. This planar array demonstrates state-of-the-art design technology required for implementation of Ka-band transmit arrays in future NASA (US National Aeronautics and Space Administration) deep-space missions. >
10 citations
01 Jan 1990
TL;DR: A 32 GHz, twenty-one element array feed incorporating 63 MMIC devices and providing electronic beam steering using 21 VLSI silicon control chips is under development at NASA's JPL as mentioned in this paper.
Abstract: A 32 GHz, twenty-one element array feed incorporating 63 MMIC devices and providing electronic beam steering using 21 VLSI silicon control chips is under development at JPL. The design improves on our earlier experience using a novel "building block" approach to construct a six element linear transmit array. design is to be used for NASA deep space communications applications. The final array feed
9 citations
09 Dec 1990
TL;DR: In this article, the ring-bar design is presented along with the RF performance data on one of the development tubes, which is directed toward a 800-W tube operating at 35 GHz, at duties up to 30%.
Abstract: A detailed description of the ring-bar design is presented along with the RF performance data on one of the development tubes. Performance tests have demonstrated in excess of 700 W at 31 GHz. The tube features periodic permanent magnet (PPM) focusing, conduction cooling, and a nonintercepting gridded gun design. Helix derived circuits such as the ring-bar circuit offer several advantages over traditional helix circuits, including higher power levels, higher efficiencies, and improved thermal capabilities while maintaining equivalent costs. This development program is directed toward a 800-W tube operating at 35 GHz, at duties up to 30%. >
7 citations
TL;DR: In this article, the use of a high-speed optical interconnect in the control of a Ka-band GaAs monolithic phase shifter is described, where a 16-b serial control signal was used to modulate the output of a laser transmitter, and the transmitted optical signal was detected and demultiplexed into 16 parallel electrical outputs using a high speed hybrid GaAs optoelectronic integrated circuit.
Abstract: The use of a high-speed optical interconnect in the control of a Ka-band GaAs monolithic phase shifter is described. A 16-b serial control signal was used to modulate the output of a laser transmitter, and the transmitted optical signal was detected and demultiplexed into 16 parallel electrical outputs using a high-speed hybrid GaAs optoelectronic integrated circuit. Four of the parallel output lines were interfaced to the 4-b phase shifter, and high-speed, optically controlled switching of the phase shifter was observed at clock frequencies to 30 MHz using an interferometric technique. >
6 citations
TL;DR: In this paper, a wideband, ground-plane DC block and bias feed for microstrip transmission lines operating in Ka-band, 26.5-40.0 GHz, is described.
Abstract: The realization of a wideband, ground-plane DC block and bias feed for microstrip transmission lines operating in Ka-band, 26.5-40.0 GHz, is described. The waveguide-to-microstrip fixture and transition used for testing are described. Analysis of the ground-plane bias gap structure is provided. A few possible applications are discussed. >
6 citations
01 Dec 1990
Abstract: We have developed and tested a 21 element two-dimensional power-combining array, intended for transmitter applications in future deep space missions. The array uses MMIC phase shifters for beam scanning, MMIC power amplifiers and Vivaldi (Exponentially Tapered Slot Antenna) radiating elements. The measured combining efficiency, referred to the power amplifier output ports, is about 60%.
5 citations
5 citations
01 Jan 1990
TL;DR: System design tradeoffs are performed and multiple access schemes are compared with the design goal of achieving the highest capacity and efficiency, and conclusions regarding the efficiency and achievable capacities are given.
Abstract: System capability is critical to the economic viability of a personal satellite communication system Ka band has significant potential to support a high capacity multiple access system because of the availability of bandwidth System design tradeoffs are performed and multiple access schemes are compared with the design goal of achieving the highest capacity and efficiency Conclusions regarding the efficiency of the different schemes and the achievable capacities are given
4 citations
01 Jan 1990
TL;DR: In this article, the authors proposed using fiber optics as a transmission line for control information for the MMICs, taking advantage of the small size, lightweight, mechanical flexibility and RFI/EMI resistant characteristics of fiber optics to distribute MMIC control signals.
Abstract: Phased array antennas long were investigated to support the agile, multibeam radiating apertures with rapid reconfigurability needs of radar and communications. With the development of the Monolithic Microwave Integrated Circuit (MMIC), phased array antennas having the stated characteristics are becoming realizable. However, at K-band frequencies (20 to 40 GHz) and higher, the problem of controlling the MMICs using conventional techniques either severely limits the array size or becomes insurmountable due to the close spacing of the radiating elements necessary to achieve the desired antenna performance. Investigations were made that indicate using fiber optics as a transmission line for control information for the MMICs provides a potential solution. By adding an optical interface circuit to pre-existing MMIC designs, it is possible to take advantage of the small size, lightweight, mechanical flexibility and RFI/EMI resistant characteristics of fiber optics to distribute MMIC control signals. The architecture, circuit development, testing and integration of optically controlled K-band MMIC phased array antennas are described.
4 citations
TL;DR: In this paper, a high-voltage DC block is proposed for use in the microstrip ground plane, and empirical results of the passband characteristics of the block are presented.
Abstract: A novel high-voltage DC block is discussed for use in the microstrip ground plane. Empirical results of the passband characteristics are presented.
01 Oct 1990
TL;DR: In this article, an integrated dual fequency LO subsystem is presented that provides LO signals for a converter system that downconverts signals in the 18 - 40 GHz range (subranges 18 - 26; 26 - 34; 34 - 40GHz) into the 4 - 8 GHz band (1).
Abstract: In the paper an integrated dual fequency LO subsystem will be presented that provides LO signals for a converter system that downconverts signals in the 18 - 40 GHz range (subranges 18 - 26; 26 - 34; 34 - 40 GHz) into the 4 - 8 GHz band (1). The LO frequencies for these conversions are 26 GHz, 30 GHz, and 34 GHz. One LO subsystem generates two (of the above mentioned three) frequencies, phaselocks them to the provided references and multiplexes them to the LO OUT port of the subsystem.
01 Dec 1990
TL;DR: In this article, two uniplanar mixer designs are described for broad-band monolithically integrated mixers which utilize surface-oriented hot electron devices as nonlinear elements.
Abstract: Two new uniplanar mixer designs are described. These mixers are being tested at ifA-band, but will be scaled to higher millimeter wave frequencies. The goal is to develop broad-band monolithically integrated mixers which utilize surface-oriented hot electron devices as nonlinear elements.
03 Sep 1990
TL;DR: FODA (FIFO ordered demand assignment) a TDMA (time division multiple access) satellite access scheme suitable for simultaneous transmissions of real-time and bulk data is described, able to efficaciously counter deep fades due to rain attenuation at high frequencies.
Abstract: FODA (FIFO ordered demand assignment) a TDMA (time division multiple access) satellite access scheme suitable for simultaneous transmissions of real-time and bulk data is described. It is able to efficaciously counter deep fades due to rain attenuation at high frequencies, always maintaining a good channel optimization. The FODA system, using adaptive bit and coding rates, is designed to obtain the maximum out of a satellite channel in any condition. The system, already operating at 2 Mbit/s with 1/2 coded or uncoded data, is in the middle of partial redesign to cope with fades of the signal due to bad atmospheric conditions when operating in the Ka band. The reaction of the system to the fade effect is shown. The results of a deterministic study on frame utilization when fades must be countered are also presented. >
Dissertation•
01 Jan 1990
TL;DR: This thesis is based on aspects of CODE systems design and link simulation that have been undertaken as part of the design process for CODE, a Ka-band point-to-multipoint Very Small Aperture Terminal network using the European Space Agency experimental Olympus satellite.
Abstract: The pressure to move upwards from the 12/14 GHz Ku-band used for satellite communications is likely to increase in the 1990's, as spectrum congestion increases. The next available exclusive satellite band after the Ku-band is the 20/30 GHz Ka-band. The Ka-band has a 3.5 GHz bandwidth allocation, which compares favourably with a 1 GHz allocation at Ku-band. There are a number of drawbacks with operation at Ka-band, principally severe fading and a lack of cheap, reliable microwave components. There is also at present, limited experience in the design and operation of satellite systems at Ka-band in Europe. The Co-operative Olympus Data Experiment (CODE) is a Ka-band point-to-multipoint Very Small Aperture Terminal (VSAT) network using the European Space Agency experimental Olympus satellite. The Satellite Research Group at the University of Surrey, as part of an international design team for the CODE system, have contributed to aspects of CODE system design and link simulation. This thesis is based on aspects of CODE systems design and link simulation that have been undertaken as part of the design process for CODE. The systems design study includes detailed link budgets for the inbound and outbound links. VSAT parameters such as antenna size, amplifier power rating and LNA noise figure are specified for various European locations. Interference and the effect of solar outages on link performance are also considered. The inbound and outbound CODE links have been modelled using the TOPSIM III and BOSS simulation packages. Phase noise has been included in the simulation models, and the simulation results have been supplemented by hardware measurements using a satellite simulator and the Olympus satellite. The link simulation studies and hardware measurements have allowed a number of critical system parameters to be identified enabling a number of recommendations to be made regarding key CODE system specifications.
01 Jan 1990
TL;DR: In this paper, the use of satellites in elliptical orbits for a Ka-band personal communications system application designed to provide voice and data service within the continental U.S. is examined.
Abstract: The use of satellites in elliptical orbits for a Ka-band personal communications system application designed to provide voice and data service within the continental U.S. is examined. The impact of these orbits on system parameters such as signal carrier-to-noise ratio, roundtrip delay, Doppler shift, and satellite antenna size is quantized for satellites in two elliptical orbits, the Molniya and the ACE orbits. The number of satellites necessary for continuous CONUS coverage has been determined for the satellites in these orbits. The increased system complexity brought about by the use of satellites at such altitudes is discussed.
07 May 1990
TL;DR: In this paper, a high-speed hybrid GaAs optoelectronic integrated circuit (OEIC) was used to control a 28.2 GHz eight-element phased array antenna, which accepts a serial optical control signal as input and converts it to 16 demultiplexed parallel outputs.
Abstract: Optical distribution of control signals in electronically steered phased array antennas is considered. A demonstration experiment in which a high-speed hybrid GaAs optoelectronic integrated circuit (OEIC) was used to control a 28.2 GHz eight-element phased-array antenna is described. The OEIC, which accepts a serial optical control signal as input and converts it to 16 demultiplexed parallel outputs, was used to control the monolithic GaAs phase shifters of a Ka-band patch panel array antenna. Antenna pattern switching speeds of 2.25 mu s, limited by interface circuitry, were observed. >
TL;DR: In this paper, a fast scanning frequency meter was developed for frequency measurements of microwaves generated in the pulsed gyrotron, using a voltage controlled oscillator (VCO) as the local oscillator.
Abstract: A fast scanning frequency meter was developed for frequency measurements of microwaves generated in the pulsed gyrotron. The heterodyne technique, using a voltage controlled oscillator (VCO) as the local oscillator, was utilized in order to shorten the measuring time. The frequency coverage of this meter is in the range of 26.5–31.2 GHz. The minimum measuring time is 100 μs(10 kHz) with a measurement error of less than ±23 MHz.
26 Mar 1990
TL;DR: In this paper, a miniature image rejection mixer has been made which covers the KA Band in suspended microstrip form using quartz substrates for durability, and the local oscillator is applied to a fin-line port resulting in low spurious outputs.
Abstract: A miniature image rejection mixer has been made which covers the KA Band. It is in suspended microstrip form using quartz substrates for durability. The local oscillator is applied to a fin-line port resulting in low spurious outputs. A novel microstrip to fin-line transition is used.
24 Sep 1990
TL;DR: In this article, normalized radar cross section and Doppler spectra were measured at 35 GHz (8.6 mm) at 51.5° incidence angle for vertical polarization, as a function of wind stress and longwaves.
Abstract: Using the NRL wind-wave facility, normalized radar cross section and Doppler spectra were measured at 35 GHz (8.6 mm) at 51. 5° incidence angle for vertical polarization, as a function of wind stress and longwaves. The data are consistent with Bragg scattering, and agree well with aircraft measurements at a similar frequency conducted by Masuko et al. Comparing the resul ts with the model predictions of Plant and of Donelan and Pierson reveals large discrepancies between the models and the data. The results indicates both the incompleteness of our understanding of the radar backscatter at millimeter wavelengths and the importance of possible improvements.