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Rusch, W. V. T.

Publications and source records attributed to Rusch, W. V. T..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Focal shifts in parabolic reflectors

The case of a parabolic reflector and a point feed is considered, taking into account the question regarding the location in which the feed should be placed for an achievement of maximum directivity. Based on the tracing of geometrical rays, the obvious answer is obtained that the feed should be placed at the focal point. In the present paper, it is shown that this answer is not always correct. There are situations in which the maximum directivity is achieved when the feed is axially displaced toward the reflector or away from it. This 'focal shift' phenomenon is a result of three competing factors which affect the directivity of a reflector. The factors are related to phase synchronism over the reflector aperture, aperture illumination efficiency, and spillover loss. For achieving the maximum directivity, it is necessary to find the best compromise among the three factors.

Ling, H.↗
NASA NTRS1985

VLBI collimation-tower technique for time-delay studies of a large ground-station communications antenna

A need for an accurate but inexpensive method for measuring and evaluating time delays of large ground antennas for VLBI applications motivated the development of the collimation tower technique. Supporting analytical work which was performed primarily to verify time delay measurement results obtained for a large antenna when the transmitter was at a collimation distance of 1/25 of the usual far field criterion is discussed. Comparisons of theoretical and experimental results are also given.

Otoshi, T. Y.↗
NASA NTRS1983

VLBI collimation tower technique for time-delay studies of a large ground station communications antenna

A need for an accurate but inexpensive method for measuring and evaluating time delays of large ground antennas for VLBI applications motivated the development of the collimation tower technique. Supporting analytical work which was performed primarily to verify time delay measurement results obtained for a large antenna when the transmitter was at a collimation distance of 1/25 of the usual far field criterion is discussed. Comparisons of theoretical and experimental results are also given.

Otoshi, T. Y.↗
NASA NTRS1978

Microwave delay characteristics of Cassegrainian antennas

A technique is presented in which the time an RF signal is delayed in propagating through a Cassegrain antenna is determined. The technique utilizes the group delay time and the envelope delay time as found from the antenna transfer function. The calculations show that a focused antenna is basically a nondispersive device whose delay time may be found from an optics formula. Small subreflector displacements result in significant delay changes requiring calibrations for many applications.

Cha, A. G.↗
NASA NTRS1972

Net-field polarization in a magnetically biased plasma.

Systematic treatment of the net-field polarization of a plane wave propagating in a magnetically biased cold plasma. Polarization transformations under quasi-longitudinal conditions are examined. The wide variety of polarization transformations available suggests the usefulness of slabs of magnetically biased plasma to synthesize microwave polarizers and depolarizers.

Rusch, W. V. T.↗
NASA NTRS1971

Non-symmetrical two dimensional scattering program

Computer program, 2DSCAT, solves integral equation for currents induced by electric or magnetic plane wave incident upon one or more conducting cylinders. Subroutine, FIELD, assumes that an incident wave is perpendicular to the cylindrical surface. Restrictions on this program are given.

Hatfield, J.↗
NASA NTRS1971

Symmetrical two dimensional scattering program

Computer program solves integral equation for currents induced by electric or magnetic plane wave incident upon one or more conducting cylinders with a midplane of symmetry. Program utilizes symmetry of the geometry. Restrictions on the program are given.

Hatfield, J.↗
NASA NTRS1970

Analysis of reflector antennas

Monograph on analysis of reflector antennas covering electromagnetic field equations, computer aided design, etc

Patter, P. D.↗