Yutaka Ida

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.

Novel bandpass filter using couplers and resistors for millimeter-wave MMIC application

A new passive bandpass filter with a planar structure using directional couplers and resistors is proposed. The characteristics of the filter are examined up to the millimeterwave frequency band. The parameter dependence of the filter is calculated and it is found that this new filter has a potential to obtain lower insertion loss and higher selectivity characteristics than conventional filters. It can also provide a high return loss in a wide frequency band range. This new filter is practical for application to mm-wave MMICs.