Abstract:A new one–dimensional periodic defected ground unit structure is proposed in order to improve the effective inductance. Increasing the effective inductance makes it easy to control the cutoff frequency characteristics of the DGS planar circuits. The proposed period Defected Ground Structure (DGS) provides the excellent cutoff and stopband characteristics. In order to show the improved effective inductance, three DGS circuits are fabricated with identical period and different dimensions. Measurements on the fabricated DGS circuits show that the cutoff and stopband center frequency characteristics depend on the physical dimension of the proposed unit lattice.