High compactness / high isolation 3D-broadside couplers design methodology

This paper presents an analytical design methodology for 3D broadside couplers using new concept of compensation by coupled lines at both ends of a main coupler section. This compensation technique introduces a degree of freedom in the design which can enhance the compactness or the isolation of the coupler. Simulations have been performed and good agreement with the analytical analysis is observed. Two demonstrators have been then optimized and demonstrate a size reduction of 50% or a 10 dB isolation improvement depending on the compensation scheme followed.