Directional Cuplers with Very Flat Cuplings using Π Guide

In this work, the π guide is proposed as an alternative to increase the bandwidth of the proximity directional couplers made. with dielectric guide and capable of giving a coupling factor practically constant with the frequency. Two theoretical methods have been used in the analysis of the coupled guides: the effective dielectric constant method and Schelkunoff's method. The inclusion of metallic walls, in the curved zones, avoid additional couplings and reduce the radiation losses allowing, furthermore, the fine adjustment of the coupling.