Dan A. Bathker

Beam-waveguide antenna performance predictions with comparisons to experimental results

An overview of a NASA/JPL antenna project, with specific focus on the methodology used to predict the microwave performance of a 34-m-diameter beam-waveguide (BWG) reflector antenna, designated DSS 13, is given. Microwave performance predictions are given, as well as a summary of test results for the antenna, which has Cassegrain and centerline BWG operating models at X-band (8.450-GHz) and Ka-band (32-GHz) frequencies. Predictions were used to identify critical and poorly understood areas needing further study and diagnostic testing, and assisted in planning, scheduling, and evaluating the final results of a detailed test program. Predictions were assembled for all known losses that contribute to antenna performance degradation. It was found that predictions and experimental results agreed reasonably well for beam-peak gain and corresponding efficiency, and for several (but not all) noise temperatures. >

Design considerations for beamwaveguide in the NASA Deep Space Network

A generalized solution is found for retrofitting a large dual-shaped reflector antenna for a beamwaveguide. The design is termed as a bypass beamwaveguide. Both highpass design feed imaging and bandpass design feed imaging are considered. Each design was studied using geometrical optics, Gaussian wave analysis, and both low-frequency and high-frequency diffraction analysis. An important extension of the Mizusawa-Kitsuregawa criteria was discovered (M.M. Zusama and T. Kitsuregawa, ibid., vol.AP-21, pp.844-8, Nov. 1973). The principle revealed shows how a two-reflector cell, although in itself distorting, may be combined with a second cell which compensates for the first and delivers an output beam which is a good image of the input beam. >

The Ultra Cone: An Ultra-Low-Noise Space Communication Ground Radio-Frequency System

Maximum sensitivity was required for the reception of Mariner V signals as it was occulted by the planet Venus. To meet this requirement, an ultra-low-noise radio-frequency system (ultra cone) was developed for the JPL/NASA Deep Space Instrumentation Facility (DSIF). The system consisted of an 85-foot antenna with a Cassegrain feed, low-noise transmission line components, and closed-cycle refrigerated maser amplifier. The antenna (at zenith), transmission line, and maser contributed about 9/spl deg/K, 2/spl deg/K, and 5/spl deg/K, respectively, for a total operating noise temperature of approximately 16/spl deg/K. The antenna feed, maser system, and calibration techniques are described in detail.

Gaussian beam and physical optics iteration technique for wideband beam waveguide feed design

A novel approach is demonstrated which involves iterating Gaussian beam and beam waveguide (BWG) parameters to obtain a wideband BWG feed. The result is further improved by making a comparison with the physical-optics result and repeating the iteration. The basic goal was to design a BWG feed system with good performance from 2 to 32 GHz, utilizing mirror sizes of 20 lambda at the low frequency. The BWG antenna performance (e.g. gain, efficiency, noise temperature) at S, X, and Ka-bands is presented. It is noted that higher-gain horns are needed for higher frequencies.<<ETX>>

The High-Power X-Band Planetary RADAR at Goldstone: Design, Development, and Early Results

Selected critical microwave components for a 400-kW very-long-pulse (several hours) X-band RADAR system are discussed from theoretical and practical viewpoints. Included are the special-sized waveguide and flanges, hybrid power combiner, couplers, switches, polarizer, rotary joints, feedhorn, and radome. The system is installed on the National Aeronautics and Space Administration/Jet Propulsion Laboratory 64-m-diam reflector antenna at Goldstone, CA.

Lunar range radiation patterns of a 210-foot antenna at S-band

Far field radiation patterns of Advanced Antenna System presented by Surveyor I on lunar surface

A new technique for vernier pointing of a beam-waveguide antenna

This paper presents a new and simple approach for the Ka-band vernier pointing of a 34 m beam-waveguide (BWG) antenna (also applicable to a 70 m antenna). In this study, rotation of a BWG flat mirror, located at the elevation axis, is used to scan the beam instead of using the very large tipping structure of the antenna. The rotation of a BWG flat minor at another location is also investigated. The advantages of scanning the drastically smaller mirror with a less precise mechanism will be discussed. RF performance predictions will be presented.<<ETX>>