Reflectionless Wideband Bandpass Filter Designed With Multilayered Microstrip Vertical Transition

Abstract

In this paper, a symmetrical wideband bandpass filter (BPF) with reflectionless behavior is presented via multi-layered microstrip vertical transition. By employing two resistively-terminated microstrip lines printed on the top and bottom layers of this proposed multilayered BPF, ultra-broad input/output reflectionless capabilities along with wideband filtering performance intrinsic to this circuit structure can be achieved. The operational principle of this designed BPF is theoretically discussed. For experimental-validation purposes, a multilayered filter prototype is simulated and fabricated. It exhibits a measured wideband filtering response centered at 1.91 GHz and power-matching levels better than 19.27 dB from 0 to 3.75 GHz.