Experimental design of bandstop filters based on unconventional defected ground structures (original) (raw)

A modified design of band stop filters using unconventional defected ground structures (DGS) is presented. The new proposed structures have conventional dumbbell DGS and spiral DGS integrated with U-slots. These microstrip structures provide high selectivity and Q-factor. By integrating the U-slot to the conventional structures, the overall capacitance and inductance increase which results in shift of resonance frequency from3.434 GHz to2.323 GHz for modified dumbbell and from 1.818 GHz to 1.702 GHz for modified spiral structure. Sharp transition is achieved from pass band to stop band and reduced ripples in the pass band for the new proposed DGS while the DGS sizes remain the same. The proposed designs were fabricated and tested on a dielectric substrate with dielectric permittivity of 10. V