A Dual Passband Filter using Hybrid Microstrip Open Loop Resonators and Coplanar Waveguide Slotline Resonators

Abstract

A novel dual passband filter using hybrid microstrip open loop resonators and coplanar waveguide (CPW) slotline resonators is proposed. With the CPW feeding structure, the center frequencies and 3-dB fractional bandwidth (FBW) can be achieved relatively independently. The external quality factor and coupling coefficient of the resonators are obtained. The proposed dual passband filter has center frequencies of 2.44 GHz and 3.5 GHz, which could be appropriately used for wireless local area networks (WLAN) and WiMax. Good agreement between simulated and measured results is demonstrated.