DESIGN OF DUAL-BAND SIR BANDPASS FILTER WITH A BROAD UPPER REJECTION BAND FOR WLANS

In this letter, we proposed the design of novel dual-band bandpass filter (BPF) with a broad upper rejection band using old v two asymmetric stepped impedance resonators (SIRs), which has a smaller circuit size in comparism of previous works. The feature of the asymmetric SIR is only one-step discontinuity, which is different from the conventional SIR with two-step discontinuities. By selecting properly the impedance ratio (R) and physical length ratio (alpha) of the proposed asymmetric SIRs. the low loss dual-band BPF centered at 2.4/5.2 GHz with a wide upper rejection band from 6 to 14 GHz can be implemented perfectly. The bandwidths and the coupling coefficients of the two passbands can be tunable by adjusting the coupling gap distance between the resonators, which are calculated by using full-wave simulator IE3D. Good agreement between the electromagnetic (EM) simulation and measurement is reported. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1143-1146, 2009: Published online in Wiley Interscience (WWW.interscience.wiley.com). DOI 10.1002/mop.24227