Compact Microstrip Band-pass Filter Using Open-loop Square Shaped DGS

Abstract

This paper presents to implement a compact microstrip band-pass filter with open-loop square dumbbell-shaped defected ground structure (DGS). This filter is designed at 2.1 GHz center frequency. The prototype filter is with defected ground structure to provide higher order quasi-elliptic filtering and it reports the return loss of 39 dB with a 3 dB fractional bandwidth of 880 MHz. The bandwidth of the band-pass filter can be easily controlled by adjusting open-end locations along with the two loops of the DGS unit. This filter is simulated with method of moments (MOM)-based IE3D simulation software