Compact Dual-Band Bandpass Filter with Adjustable Passbands Using Open Stubs

A dual-band bandpass filter is discussed in this paper. To obtain adjustable passbands, four open stubs are embedded into a rectangle ring. The first resonant frequency is related to the rectangular ring and two of stubs, and the second resonant frequency is to all stubs. By adjusting these stubs, the size of the filter can be reduced, and dual-band can be tackled significantly. Based on the proposed topology, a prototype was fabricated to achieve dual-band applications around 2.08 and 3.8 GHz. Experiment results demonstrate newly designed filter available.