Design of compact ultra-wideband filter using stepped impedance dual-mode resonator

Abstract

A compact ultra-wideband (UWB) filter is designed by a proposed stepped impedance dual-mode resonator. The dualmode resonator is formed by adjusting the impedance ratio. There are four resonant modes inside pass-band of the novel filter, two of which are generated by dual-mode resonator and the other two modes are produced by parallel-coupled feed lines. This results in the formulation of the novel UWB filter with wide bandwidth and compact size. The measured results show that the 10 dB pass-band of the novel filter is from 5.2 GHz to 10.9 GHz and fractional bandwidth of up to 70%. The Simulated results are agreement well with the measured results.