Intermodulation scattering communications apparatus

Abstract

Abstract Multiple beam, multi-frequency communication apparatus (10) that provides for significant intermodulation scattering improvements for multiple beam, multi-frequency communications systems implemented using directly radiating active phased array (15), or multi-feed reflector systems fed from composite, multiple shared transmit amplifiers (13). The multiple bearn, multi-frequency communications apparatus (10) comprises a defocused antenna array (15) having a plurality of antenna elements (15a) and a plurality of feeds (15b). A hybrid amplifier structure (18) is coupled to the feeds (15b) of the defocused antenna array (15) and shares the plurality of transmit amplifiers (13) among the feeds (15b) of the antenna array (15). Assignment apparatus (20) is coupled to the hybrid amplifier structure (18) for assigning particular transmit amplifier (13) to be contributors to particular beams (16) radiated by the antenna array (15) in response to a desired beam profile (11). Improvements result from judicially combining the effects of the shared transmit amplifiers (13) (that carry all the signals in the frequency reuse system), with phasing effects inherent in rhe multiple beam radiating structure in order to realize the desired zonal frequency reuse pattem 21. An optimal assignment algorithm implemented in the assignment apparatus (20) results in a uniform distribution of power over the transmit amplifiers (13), resulting in corresponding improvements in system performance in the far field.

Inventors

• 👤 Arnold L. Berman
• 👤 James D. Thompson
• 👤 Michael I. Mandell

Bibliographic Details