Design of High-Performance Lowpass Filter Using Inter-Coupled Compact Microstrip Resonator Cells

Abstract

This paper presents a high-performance lowpass filter (LPF) using periodical inter-coupled compact microstrip resonator cells (CMRCs) in series. The CMRC consists of high impedance transmission line and symmetrical T-shaped structure at both sides with ended transmission line arms. By using a bridge structure to introduce controllable inter-coupling between the adjacent tapered CMRC units, the proposed CMRC structure exhibits quasi-elliptic lowpass response with improved stopband performance. Final design of an exemplary LPF using proposed design structure and methodology verify the feasibility of the structure and its high performance including compact structure, low insertion loss, sharp transition and expanded stopband.