A compact low pass filter design with a fan-shaped defected ground structure for broad stopband

Abstract

The aim of the paper is to acquire low pass filter with broad stopband frequency characteristics. To achieve this, a novel fan-shaped defected ground structure (DGS) is presented and compared with other conventional simple DGS units such as square, circular and elliptical. Furthermore, effects of slot length variation of the novel DGS unit are analyzed. Finally, top side of the structure is modified adding several impedance lines to the center of the microstrip line to obtain broad stopband. Designed filter is quite compact with a dimension of 20 mm × 14 mm × 1.27mm. Simulations of design procedure are achieved with ANSYS HFSS and SONNET.