A compact wideband filter utilizing stepped-impedance transformer and stubs

Abstract

This paper proposes a compact wideband filters consisting of a stepped-impedance transformer. The stepped-impedance transformer is loaded by two short-circuited stubs and a pair of open-circuited stubs. A wideband bandpass filter operated from 3.71 GHz to 7.28 GHz has been designed and simulated. The designed filter has also been fabricated for validation. The fabricated filter exhibits a 60% bandwidth and occupies an area of 8.6 × 8.35 mm2. A compact and wideband filter is therefore obtained.