Study on Stepped Impedance Comb-line Filter with Defected Ground Structure

摘要

A stepped impedance comb-line filter with defected ground structure (DGS) is proposed. The filter consists of two stepped impedance microstrip resonators. By using DGS, a coupling capacitor is inserted into the ground plane in order to build strong coupling locally along the resonators. The filtering characteristics were investigated through numerical simulations by means of FDTD method. Filtering characteristics that have attenuation poles at both sides of the passband were obtained. We discussed the input susceptances of even and odd modes.