Alternative beam efficiency calculations for a LargeAperture MultipleFrequency Microwave Radiometer (LAMMR)
Abstract
The fundamental definition of beam efficiency, given in terms of a far field radiation pattern, was used to develop alternative definitions which improve accuracy, reduce the amount of calculation required, and isolate the separate factors composing beam efficiency. Wellknown definitions of aperture efficiency were introduced successively to simplify the denominator of the fundamental definition. The superposition of complex vector spillover and backscattered fields was examined, and beam efficiency analysis in terms of power patterns was carried out. An extension from single to dual reflector geometries was included. It is noted that the alternative definitions are advantageous in the mathematical simulation of a radiometer system, and are not intended for the measurements discipline where fields have merged and therefore lost their identity.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 December 1979
 Bibcode:
 1979STIN...8017327S
 Keywords:

 Far Fields;
 Microwave Radiometers;
 Power Gain;
 Radio Astronomy;
 Antennas;
 Mathematical Models;
 Microwave Imagery;
 Parabolic Reflectors;
 Communications and Radar