Design of Microstrip-Slotline Ring 3 dB Directional Couplers with Offset Center Frequencies

Abstract

Principle of operation and analysis of microstrip-slotline ring 3 dB directional couplers featuring an offset between the center frequencies of two coupling characteristics is presented. Potential applications of such couplers include various balanced nonlinear and parameetric circuits. Theoretical and experimental characteristics of three couplers designed to possess the centre frequencies of 4 and 12 GHz, 6 and 12 GHz, 10.7 and 12 GHz are also given.