CAD-oriented design of interdigitated coplanar directional coupler

Abstract

This paper presents a CAD-oriented design procedure for the interdigitated coplanar directional coupler. It is based on interdigitated coupler equations and conformal mapping techniques and takes into account the width difference in the interdigitated structure and the finite thickness of the substrate. Performance measurement of a sample designed and constructed on 0.635 mm thick alumina shows close agreement with the theoretical results.