Feldtheoretische Analyse und Synthese von Modenkopplern

Analytical and experimental studies of rectangular-waveguide mode couplers for geostationary-satellite position-stabilization telemetry units are presented. Orthogonal expansion methods are employed to investigate transverse discontinuity, longitudinal branching, and T-junctions, taking the amplitude and phase of higher-order nonpropagating modes into account. The scattering matrices of the individual elements and of the coupler circuits developed by combining them are calculated, and a numerical optimization using an evolution strategy is performed. Experimental measurements using circuitry which generates an H(10)-H(20) mixture confirm the theoretical predictions and show that a mode coupler with additional asymmetrical inductive screening can achieve crosstalk suppression of greater than 50 dB with H(10)-channel operating-frequency damping of less than 0.35 dB.