Compact UWB Bandpass Filter With Triple-Notched Bands Using Triple-mode Stepped Impedance Resonator

Abstract

In this letter, a compact ultra-wideband (UWB) band-pass filter (BPF) with triple-notched bands is presented using a novel triple-mode stepped impedance resonator (SIR). The basic UWB BPF is comprised of four folded shunt quarter-wavelength short-circuited stubs separated by connecting lines with length of λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g0</sub> /4 and λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g0</sub> /2, respectively. The proposed coupled triple-mode SIR is found to have the advantages of introducing triple-notched bands and providing higher degree of freedom to adjust the resonant frequencies. The simulated and measured results are in good agreement with each other, showing good wideband filtering performance with sharp rejection skirts outside the passband.