COMPACT WIDE STOPBAND LOWPASS FILTER USING RECTANGULAR PATCH COMPACT MICROSTRIP RESONANT CELL AND DEFECTED GROUND STRUCTURE

摘要

A new compact microstrip low-pass filter (LPF) is presented using a novel rectangular patch compact microstrip resonant cell (RPCMRC) and square-head defected ground structure (DGS). It exhibits wide, high stopband, and sharp rejection. A demonstration LPF having 3 dB cutoff frequency of 2.65 GHz was fabricated and measured. Measured rejection is better than 20 dB from 2.8 to 16 GHz. Electrical length of the filter is less than 20% of the guided wavelength at 3 dB cutoff frequency. Measured passband to stopband attenuation slope is more than 56 dB/GHz. Good match between experimental and simulated results are obtained.