A CPW bandstop filter using double hairpin-shaped defected ground structures with a high Q factor

Abstract

A new coplanar waveguide bandstop filter using double hairpin-shaped defected ground structures is proposed. The proposed bandstop filter is composed of double hairpin-shaped defected ground structures etched on the ground plane of a coplanar waveguide, and can provide a narrow bandwidth rejection with a high Q factor. Numerical simulations revealed that the bandwidth and resonance frequency of this device can be controlled by adjusting the parameters of the defected ground structure. Moreover, numerical simulations and measurements revealed that a cascade of coplanar waveguides with double hairpin-shaped defected ground structures can increase the bandwidth, and attenuation level in the rejection band. Optimized cascaded coplanar waveguides loaded with double hairpin-shaped defected ground structures provide a Q factor of 21.1 with more than -40 dB suppression at 4.67 GHz. In many RF applications, this filter will be effective in rejecting unwanted signals with a high Q factor.