Design and Analysis of Defected Ground Structure for Microwave Planar Filters

Abstract

Adesignofdefectedgroundstructureispresentedinthispaper.The defected ground unit lattice improves the effective inductance. Increasing the effective inductance makes it easy to control the cutoff frequency characteristics. The proposed defected ground structure (DGS) provides excellent cutoff and stopband characteristics. In order to show the improved effective inductance, agroup of DGS circuits were designed with different periods and different dimensions. Simulation results show that the cutoff and stopband center frequency characteristics depend greatly on the physical dimension as well as period of the proposed DGS unit lattice. The frequency response obtained can be usefully utilized in design of various microwave planar filters. Detailedanalysis of the numericaland measuredresults hasbeencarriedout in this paper.