A novel semilumped low-pass filter having finite frequency attenuation poles with defected ground structure

This paper presents the design and analysis of a novel filter configuration offering infinite attenuation at finite frequencies. The proposed filter has a cut-off frequency of 2 GHz with passband ripple of 0.1dB and a minimum stopband insertion loss greater than 40dB at 3.05GHz. The two infinite attenuation poles occur at 2.4GHz and 2.76GHz. In order to further enhance the filter performance, the elliptical response filter has been embedded with a dumbbell shaped defected ground structure and the results are analyzed.