CSI PROPOSES TO DEMONSTRATE THE FEASIBILITY OF HIGH EFFICIENCEY MULTI-FREQUENCY ANTENNA FEED SYSTEMS COMBINING THE HIGH-EFFICIENCY ADVANTAGES OF NEAR-FIELD CASSEGRAIN TECHNIQUES (DUAL-REFLECTOR SHAPING, LOW TRANSMISSION LINE LOSSES) WITH THE

CSI PROPOSES TO DEMONSTRATE THE FEASIBILITY OF HIGH EFFICIENCEY MULTI-FREQUENCY ANTENNA FEED SYSTEMS COMBINING THE HIGH-EFFICIENCY ADVANTAGES OF NEAR-FIELD CASSEGRAIN TECHNIQUES (DUAL-REFLECTOR SHAPING, LOW TRANSMISSION LINE LOSSES) WITH THE MULTI-FREQUENCY AND SIMPLICITY ADVANTAGES OF THE COAXIAL CAVITY APEX FEED. THE COAXIA CAVITY APEX FEED WILL BE USED TO FEED THE PRIMARY REFLECTOR IN THE NEAR-FIELD CASSEGRAIN FEED SYSTEM. CIS WILL GENERATE A COMPUTER MODEL OF THIS FEED SYSTEM DURING PHASE 1, AND USE IT TO SYNTHESIZE OPTIMUM DESIGNS FOR3.7 AND 6.0 METER DIAMETER REFLECTOR ANTENNAS OPERATING AT S,X, AND KA BANDS (PER SUBTOPIC 14.07). THE RESULTS WILL BEA HIGH-EFFICIENCY MULTI-FREQUENCY FEED WHICH IS INEXPENSIVE TO DEVELOP AND WHOSE CONFIGURATION ACCOMMODATES NICELY RIB-AND-MESH DEPLOYABLE ANTENNA GEOMETRIES. THE COMPUTER MODEL WILL CONTAIN SOFTWARE THAT ALREADY EXISTS AT CSI, SOME OF WHICH WILL HAVE TO BE MODIFIED TO HANDLE THE NEAR-FIELD TYPE OF ILLUMINATION OF THE NEAR-FIELD FEED SYSTEM. FOR PHASE 2, A BREADBOARD OF THE FEED SYSTEM WILL BE BUILT AND TESTED TO PROVE PERFORMANCE.