Microwave Dual-Band Bandpass Filter using L-shaped Stepped Impedance Resonators

This work demonstrates a microwave dual band bandpass filter using two L–shaped stepped impedance resonators (SIRs) and a coupled feed structure. The coupled feed structure can be a single sided or a double sided structure. Two sets of physical parameters are used to control the coupling coefficient and external quality factor. Thus, the specification, such as the central frequencies and the bandwidths of both the bands, can be achieved simultaneously. Two 2.4 GHz/5.2 GHz dual band bandpass filters for wireless local area network are fabricated. Both the experimental and simulation results are provided, with good agreement. Index Terms – Bandpass filter, dual-band, stepped impedance resonator.