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.