Independently Switchable Dualband High Selective Band Pass Filter

Abstract

A novel independently switchable dual band bandpass filter is designed in this paper. A dual passband BPF centered at 2.4 GHz, and 3.5 GHz is achieved by assembling a 0° fed uniform impedance resonator and a shorted quarter wave stepped impedance resonator for Bluetooth and WiMax applications. The dual band response can be switched to two single passband response and one all stop response by making pin diodes on or off. Four transmission zeros are obtained at 2.29 GHz, 2.6 GHz, 3.3 GHz and 3.84 GHz respectively, which helps to get better passband isolation and selectivity. The filter offers a compact size of 0.25 λg ×0.11 λg at 2.4 GHz and a wide upper stopband response up to 6 GHz.