A transversal filter using CPW directional couplers

A transversal filter using coplanar waveguide (CPW) directional couplers and no active devices has been proposed. It aims to be free from the noise figure problems found in an active transversal filter and also aims to show it can be easily realized with a single-layer structure when the bandwidth is narrower than about 30%. Two types of CPW directional couplers were employed. When using G-S-G-S-G-type directional couplers, connecting section influences between strong and weak couplers were successfully suppressed.