STOPBAND IMPROVEMENT OF A DUAL-MODE RING BANDPASS FILTER USING DGS

摘要

This paper presents the improved stopband of a novel dual-mode bandpass filter (BPF) using an etched H-shaped defected ground structure (DGS) at 2 GHz. The wide-stopband characteristic results from the rejection-band resonant characteristic of the DGS in the harmonic frequency of the dual-mode BPF. The proposed BPF is designed and fabricated with the following frequency characteristics: central frequency f{sub}0 = 2 GHz, 3-dB bandwidth of 3%, and wide stopband from 2.5 to 5 GHz at -40 dB, The measured results of the fabricated filter show good agreement with the simulation results.