Topex Spacecraft Dual-Frequency Radar Altimeter Antenna,

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Abstract:

The design of the TOPEX Radar Altimeter antenna is described. The TOPEXPOSEIDON satellite is a joint U.S.-France NASA-CNES spacecraft scheduled for launch in 1992. The spacecraft will carry the TOPEX and POSEIDON radar altimeters, which will map the circulation of the global oceans. The TOPEX radar altimeter NASA is a dual-frequency altimeter operating at Ku- and C-bands. The POSEIDON radar altimeter CNES operates at Ku-band. A common antenna is used for the two altimeters. The antenna is a focal-fed 1.5 meter diameter parabolic reflector antenna. The feed includes a waveguide circuit to combine the three signals from the two altimeters. The radiating portion of the feed is a conical dual-depth corrugated scalar horn. The C-band signal is launched by a coaxial probe into the C-band circular waveguide feeding the horn. The two Ku-band signals are launched with orthogonal polarizations by an orthomode transducer. To achieve coupling at Ku-band to the horn through the large waveguide, a step discontinuity is used to generate TE11 and TM11 modes in the large waveguide.

Author(s):
Jablon, Allan R.
Author Organization(s):
JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
Supplementary Note:
This article is from 'Proceedings of the Antenna Applications Symposium Held on 25-27 September 1991. Volume 1,' AD-A253 682, p334-348.
Pagination:
0015

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Subject Terms
Modernization Areas:
Space
Communities of Interest:
Space
Descriptor(s):
*ALTIMETERS, *ANTENNAS, *ARTIFICIAL SATELLITES, *RADAR, C BAND, CIRCUITS, CIRCULAR, DEPTH, DIAMETERS, DISCONTINUITIES, FEEDING, FREQUENCY, GLOBAL, KU BAND, MAPS, OCEANS, PROBES, REFLECTORS, SIGNALS, SPACECRAFT, TRANSDUCERS, WAVEGUIDES
Field(s)/Group(s):
Flight Control and Instrumentation, Electrical and Electronic Equipment, Active and Passive Radar Detection and Equipment, Unmanned Spacecraft
Keyword(s):
Topex radar altimeter antenna, Topex poseidon satellite, Radar altimeters, Poseidon radar altimeters, Component Reports
Report Date:
1992 Feb 01