Design Procedures of Decoupling Circuit Utilizing Coupling between Antennas

Abstract

This paper presents novel design procedures for a decoupling circuit, utilizing the coupling between antennas. The proposed decoupling circuit consists of, a Band-Stop Filter (BSF) based on Coupling Matrix Synthesis (CMS) theory, a pair of matching circuits, and microstrip connecting lines. By inserting a BSF into an antenna pair, high isolation can be achieved. By utilizing coupling between antennas, the proposed BSF can be designed only using 2 parallel resonators based on the CMS theory. To maintain impedance matching of patch antennas, a pair of matching circuits is inserted after the BSF for each port. Lastly, the decoupling circuit model was fabricated. The experimental results have a good agreement with the simulation result and the validity of the proposed design method is confirmed.