A cross beam interferometer radiometer for high resolution microwave sensing

Abstract

The conceptual design of a cross beam interferometer radiometer (CBIR) for sea surface temperature sensing at 5.0 GHz is described. In a 833-km orbit, the radiometer provides 0.48 K sensitivity with a spatial resolution less than 25 km in a 1561-km swath. The radiometer consists of a pair of rectangular phased arrays in a T configuration. Each array forms ten colinear beams that project ten pairs of crossed elliptical footprints on the sea surface. The footprints from the horizontal array have minor axes that range from 14.6 km to 22.9 km and are oriented in the cross-track direction. The footprints from the vertical array have minor axes that range from 18.6 km to 25.0 km and are oriented in the along-track direction. The Mills periodic 0-180 degrees switching radio telescope technique is used to sense the variations in sea surface radio-thermal brightness temperature in the coincidence areas where the beams overlap. The CBIR concept, system design approach, antenna design and beamforming technique are described.<>