Novel design of a compact triple-band bandpass filter using short stub-loaded sirs and embedded sirs structure

Abstract

A novel compact planar triple-band bandpass filter using two sets of short stub-loaded stepped impedance resonators (SSLSIRs) and a pair of embedded stepped impedance resonators (ESIRs) has been proposed. The SSLSIRs can adjust the bandwidths of the corresponding passbands over a wide range, and the ESIRs employing non 0±-feed coupled structure with mixed electric and magnetic coupling can obtain an extra transmission zero. The embedded resonators structure can further miniaturize the dimensions of the whole triple-band filter. The operating frequencies of the SSLSIRs and ESIRs are designed for the applications of the WLAN (2.45/5.2 GHz) and WiMAX (3.5 GHz) systems, respectively. The simulated and measured results are both presented and show good agreement.