Notched ultra-wideband (UWB) bandpass filter with wide upper stopband based on electromagnetic bandgap (EBG) structures

摘要

In this paper, a new notched ultra-wideband (UWB) bandpass filter with wide upper stopband is proposed using electromagnetic bandgap (EBG) structures. The design of the UWB filter is started from a stepped-impedance stub-loaded resonator, which works as a multiple-mode resonator (MMR) and provides a UWB passband with sharp side slopes. Then, EBG-loaded lines are incorporated into the resonator to suppress the spurious responses above the passband. In order to introduce a notch for WLAN application of 5.2 GHz, a folded stepped-impedance resonator is located near to the stub of MMR. It has been demonstrated by the simulated and measured results that our proposed UWB filter has the performances of UWB passband with good frequency selectivity, narrow notched band and very wide upper stopband, simultaneously.