Design and realization of a new compact branch-line coupler using defected ground structure

Abstract

A new compact branch-line directional coupler is proposed combined the T-model branch line coupler with defected ground structure (DGS). Using transmission theory, the parameter selection limit about the T-Model equivalent structure is discussed firstly. Then a T-model branch line coupler with DGS is proposed and optimum designed with simulation software. The measurement results show that the proposed coupler has the advantages as compact and well passband flatness.