Dual-band bandpass filter design using miniaturized spiral scheme

Abstract

A compact dual-band bandpass filter using two sets of spiral resonators and loaded spiral open-stub is proposed. The dual-band resonances are introduced by the quarter-wavelength (λ/4) spiral resonator and λ/2 asymmetrical spiral stepped-impedance resonator, respectively. Then, the loaded spiral open-stub tapped on the λ/4 spiral resonator is utilized for spurious shifting close to transmission zero, which can lead to spurious suppression for extended upper stopband. Finally, a dual-band bandpass filter with good performance and size miniaturization is fabricated and verified experimentally. © 2014 Wiley Periodicals, Inc.