FEASIBILITY STUDY OF HIGH-EFFICIENCY RF-POWER COMBINERS

MODERN HF/VHF JAMMERS EMPLOY POWER COMBINERS AND MULTIPLE POWER-AMPLIFIER (PA) MODULES TO ACHIEVE A HIGH POWER OUTPUT, CANCELLATION OF HARMONICS, AND GRADUAL DEGRADATION OF PERFORMANCE DUE TO MODULE FAILURE. POWER COMBINERS CAN BE A SIGNIFICANT SOURCE OF POWER LOSS BECAUSE OF RESISTIVE LOSSES, MISMATCH (AMPLITUDE/ PHASE) OF PA OUTPUTS, AND PA INEFFICIENCY DUE TO NONNOMINAL LOAD. CURRENTAND VOLTAGE-SUMMING COMBINERS HAVE NO INTRINSIC LOSSES, BUT PROVIDE NEITHER ISOLATION NOR CONSTANT IMPEDANCE. HYBRID COMBINERS PROVIDE ISOLATION, BUT ARE INEFFICIENT WHEN THE INPUT SIGNALS DIFFER IN AMPLITUDE AND/OR PHASE. DIRECTIONAL AND QUADRATURE COUPLERS PROVIDE CONSTANT IMPEDANCE, BUT ARE INEFFICIENT FOR MISMATCHED AMPLITUDE, PHASE, OR LOAD IMPEDANCE. A VARIATION ON THE LUMPEDELEMENT WILKINSON COMBINER AND ADAPTIVE INTERCONNECTION APPEARS ATTRACTIVE. HOWEVER, EACH TYPE OF COUPLER HAS ITS OWN CHARACTERISTICS, AND A SINGLE TYPE OF COMBINER MAY NOT BE OPTIMUM FOR ALL APPLICATIONS. THE PROPOSED PROGRAM WILL CONDUCT THE GROUND WORK NECESSARY FOR SYNTHESIS AND IMPLEMENTATION OF HIGH-EFFICIENCY POWER COMBINERS. ITS PRINCIPAL COMPONENTS ARE: ANALYSIS OF DIFFERENT COMBINERS IN A COMMON FRAMEWORK, COMPARISON OF THEIR EFFECTS UPON PAS, DETERMINATION OF TRADE-OFFS BETWEEN COUPLER LOSS AND PA EFFICIENCY, AND IDENTIFICATION OF THE MOST PROMISING APPROACHES FOR DEVELOPMENT.