MICROSTRIP LOW PASS FILTER WITH WIDEBAND REJECTION USING OPENED CIRCUIT STUBS AND Z-SLOTS DEFECTED GROUND STRUCTURES

摘要

A new microstrip low pass filter (LPF) with defected ground structure (DGS) is proposed in this article. The DGSs consists of reshaped rectangular dumbbell slot and four groups of Z-shape slots. The microstrip line with DGS gave good rejection band extend from 3.0 to 9 GHz with acceptable pass band. The microstrip line with open circuit stubs (without DGS) gave good rejection band at the high frequency from 9 to 14 GHz. Using both structures results in LPF with wideband rejection from 3.37 to 14 GHz with attenuation less than (-26.0 dB) and good passband less than (-25 dB). An equivalent circuit for the proposed LPF was given. The realized filter size was 34.0×34.0 mm~2, and it gave good agreement with simulated results.