A novel CPW low-pass filter using electromagnetic band-gap structure

摘要

A novel low-pass filter with higher attenuation in rejection band is proposed in this paper, which is designed on a coplanar waveguide (CPW) structure with Electromagnetic Band Gap (EBG) structure. In order to suppress passband ripples, the mono-periodic loaded interdigital capacitors structure is modified to double-periodic loaded structure. For higher attenuation in the rejection band without increasing circuit area, EBG structures with two dual-periodic arrays of rectangular patches are etched in the ground planes. Simulation results show that the average attenuation in the rejection band for a four-pole low-pass filter with EBG structure increases about 15dB, and the rejection bandwidth is broadened about 27%, that is, 20-dB bandwidth increases from 16.1GHz to 20.5GHz. Measurement verified the above results.