Some comments on the Venus temperature.
Interpretations of microwave emission from Venus through experiments in which anomalous signals have been observed in X-band from glow discharges
PLANETARY TEMPERATURE↗
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Results for “X-Band”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Accurate method for measuring small frequency shifts in plasma loaded cavities.
Small frequency shift measurement method for X-band plasma-loaded cavities
FREQUENCY SHIFT↗
ATS-4 study program, volume 7 Final report
Direct phase reading X-band radio interferometer for attitude control of Applications Technology Satellite-4
SATELLITE INSTRUMENTATION↗
Ionization by high power microwaves.
Gas ionization and plasma heating by high power microwaves using X-band and S-band frequency magnetrons
GASEOUS IONIZATION↗
Gunn effect swept frequency oscillator.
X-band swept frequency oscillator using Gunn diode and ferrite phase shifter
Rosenbaum, F. J.↗
Characteristics of step-recovery-diode frequency multipliers
Investigation into the uses of step-recovery diodes /SRD's/ leads to the development of necessary circuitry for using fast current-switching capabilities of SRD's in frequency multiplication, the design of solid-state X-band transmitters employing SRD multipliers, and the use of SRD multipliers in a phased-array receiving antenna.
Source record↗
Lightweight S-band helix antenna
Pyrotechnically operated S-band helical antenna is developed in which helix is deployed subsequent to antenna placement. Antenna is small, lightweight, and novel in that deployable helix is used in place of fixed dish or horn. It can be designed to cover L- and X-band frequencies.
Cribb, H. E.↗
Interferometer using RF switching matrix
Radio frequency switching technique for single receiver and data processing channel to be used for phase movement measurement is discussed. Components of interferometer radio frequency unit, X-band receiver, and interferometer data processing unit are illustrated. Elimination of major measurement error source is described.
Vanvleet, R. N.↗
The variation of radar cross section with wind
X-band (8910 megahertz) and C-band (4455 megahertz) measurements indicate that two domains exist in the variation of radar cross section with wind at incident angles far from the normal. The first domain for flow windspeeds is characterized by a rapid variation of radar cross section with wind and the second domain at higher windspeeds by an asymptotic approach to an upper limit (saturation). The transaction between the two domains occurs at a windspeed of approximately 10 knots. Recent Joint Ocean Surface Study I observations tend to confirm this observation and offer additional proof of the validity of a composite surface model which relates the radar cross section of the sea to the wave-height spectrum. This confirmation was obtained by comparing the radar cross section measured by the four-frequency radar system with the radar cross section calculated from the ocean wave-height spectrum that had been determined by the optical analysis of photographs taken at the same time. A possible explanation for the wind variation of the radar cross section of the open ocean also was evolved, based on radar measurements in a wave tank under various wind conditions and subsequent comparison with optically determined spectra.
Guinard, N. W.↗
Millimeter-wave generation with spiraling electron beams
The feasibility of using the interaction between a thin, solid, spiraling electron beam of 10 to 20 kV energy and a microwave cavity to generate watts of CW millimeter-wave power was investigated. Experimental results are given for several prototype devices operating at 9.4 GHz and at 94 GHz. Power outputs of 5 W, and electronic efficiencies near 3%, were obtained at X band, and moderate gain was obtained at 94 GHz. The small-signal theory gives a good fit to the X-band data, and the device behavior at 94 GHz is as expected from the given beam characteristics. The performance is limited chiefly by the velocity spread in the spiraling electron beam, and once this can be brought under control, high-power generation of millimeter waves appears quite feasible with this type of device.
Kulke, B.↗
Polarization effects with a combined radar-radiometer
Described is a unique microwave sensor. The device uses a coherent X-band radar, a radiometer at the same wavelength and an antenna with a polarization that can be varied electronically. This microwave sensor was developed to acquire polarization signature information about various surfaces in both the active and passive mode simultaneously. One application for the sensor is expected to be the location and identification of plant life.
Martin, D.↗
A microwave-biased millimeter- and submillimeter-wave detector using InSb.
Description of a high-purity n-type indium antimonide sample mounted in a reentrant cavity, cooled to 4.2 K, and operated as a millimeter-wave detector. The scheme utilizes a down-conversion process, and free-carrier absorption is the mechanism responsible for the detection process. Power applied at the millimeter-wave frequency causes a change in the material conductivity, which in turn causes a change in the X-band power absorption. Cavity perturbation techniques are used to analyze the scheme. The detector was operated successfully at frequencies between 35 and 150 GHz with no long-wavelength or short-wavelength cutoff observed. The scheme offers a fast, highly sensitive, and rugged detector with low conversion loss.
Eldumiati, I. I.↗
Radio science experiments - The Viking Mars Orbiter and Lander.
The objective of the radio science investigations is to extract the maximum scientific information from the data provided by the radio and radar systems on the Viking Orbiters and Landers. Unique features of the Viking missions include tracking of the landers on the surface of Mars, dual-frequency S- and X-band tracking data from the orbiters, lander-to-orbiter communications system data, and lander radar data, all of which provide sources of information for a number of scientific investigations. Post-flight analyses will provide both new and improved scientific information on physical and surface properties of Mars, on atmospheric and ionospheric properties of Mars, and on solar system properties.
Michael, W. H., Jr.↗
Material injection alleviation and plasma diagnostic measurements during the RAM C-III flight.
The results of a material injection RF blackout alleviation experiment and of plasma diagnostic measurements using electrostatic probes and an S-band reflectometer in a 25,000 ft/sec reentry flight are presented. Significant alleviation of RF blackout is observed at altitudes of from 270,000 feet to 120,000 feet due to injection of water and Freon E-3 on VHF, S-band, C-band, and X-band frequencies. Electrostatic probe data, attenuation data, and S-band diagnostic data show consistent plasma results. The relative effectiveness of water and Freon E-3 is discussed.
Schroeder, L. C.↗
Electron density measurements of an inhomogeneous plasma using millimeter wave Fabry-Perot interferometers.
The electron density of a laboratory generated inhomogeneous plasma was measured using 60-90, GHz flat-plate and 150 GHz semi-confocal Fabry-Perot interferometers. The plasma was a negative glow-type and had a measured parabolic electron density profile. An analytical comparison between the derived equations of electron density for an assumed homogeneous plasma slab and an inhomogeneous plasma with parabolic distribution showed that the slab approximation was valid for such a profile. Comparison of measured values of electron density with those using X-band and K-band interferometers for the same plasma indicated good agreement.
Kendall, B. M.↗
Low noise microwave receiving systems on a 64 m antenna.
Review of the performance capability at S-, X- and K-band of the NASA/JPL 64-m Cassegrain antenna at Goldstone, California. The multiple feed system allows X- and K-band atmospheric research studies to be conducted simultaneously with mission directed S-band spacecraft tracking. A description of the antenna system and its multiple operation is followed by gain and efficiency comparisons at the three frequencies. The total operating system temperature and its frequency dependence are discussed. Antenna gain and efficiency, and zenith system operating temperature are summarized at S- and X-band, respectively, by 62 dB, 63%, 16K; and 72 dB, 52%, 24K. Preliminary measurements for K-band are 76 dB, 39%, 29K.
Reid, M. S.↗
A note on deep space optical communication link parameters
Topical communication in the context of a deep space communication link. Communication link analysis at the optical frequencies differs significantly from that at microwave frequencies such as the traditional S and X-bands used in deep space applications, due to the different technology of transmitter, antenna, modulators, and receivers. In addition, the important role of quantum noise in limiting system performance is quite different than that of thermal noise. The optical link design is put in a design control table format similar to a microwave telecom link design. Key considerations unique to the optical link are discussed.
Dolinar, S. J.↗
Science Results from the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR): Progress Report
The Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) is the most advanced imaging radar system to fly in Earth orbit. Carried in the cargo bay of the Space Shuttle Endeavour in April and October of 1994, SIR-C/X-SAR simultaneously recorded SAR data at three wavelengths (L-, C-, and X-bands; 23.5, 5.8, and 3.1 cm, respectively). The SIR-C/X-SAR Science Team consists of 53 investigator teams from more than a dozen countries. Science investigations were undertaken in the fields of ecology, hydrology, ecology, and oceanography. This report contains 44 investigator team reports and several additional reports from coinvestigators and other researchers.
Diane L Evans↗