Compact and switchable dual-band bandpass filter with high selectivity and wide stopband

• Published in: Electronics letters Vol. 49; no. 20; pp. 1275 - 1277
• Main Authors: Weng, S.-C, Hsu, K.-W, Tu, W.-H
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 26.09.2013; Institution of Engineering and Technology
• Subjects: Applied sciences; band‐pass filters; Circuit properties; circuit size miniaturisation; compact dual‐band bandpass filter; crossed coupling; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency filters; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwave technology; poles and zeros; p‐i‐n diodes; quarter‐wavelength SIR; quarter‐wavelength stepped‐impedance resonator; resonator filters; selectivity response; switchable dual‐band bandpass filter; switched filters; switching devices; transmission zeros; wide stopband; p-i-n diodes; resonator filters; quarter-wavelength SIR; crossed coupling; switched filters; poles and zeros; switchable dual-band bandpass filter; circuit size miniaturisation; quarter-wavelength stepped-impedance resonator; compact dual-band bandpass filter; band-pass filters; selectivity response; wide stopband; transmission zeros; switching devices; Multivariable control; Stepped impedance device; Crosstalk; Selectivity; Microwave filter; Natural frequency; Energy gap; Quarter wave plate; Wide band; Resonance frequency; Band pass filter; Band stop filter; Passband; Multiple frequency; Fundamental frequency
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2013.2154

A compact and independently switchable dual-band bandpass filter is presented. To achieve high selectivity response, transmission zeros beside the two passbands are generated due to crossed coupling. On the other hand, the use of quarter-wavelength stepped-impedance resonators can not only miniaturise circuit size but also widen the stopband by arranging the resonant frequencies in a stagger with the same fundamental frequency. The pin diodes are loaded at the end of the resonators as the switching devices to independently control each passband.