In this article, a new tri-band bandpass filter, operating at 2-2.6 GHz, 3.5-4.5 GHz and 5-5.8 GHz for GSM, WiMAX and WLAN application is proposed. Two quad sections SIR resonators and corresponding feeding structures are introduced to enhance the tuneable range of operating frequencies. Using source/load coupling can realize two controllable transmission zeros around each operating band. The f...
