Fully canonical dual-band bandpass filter with λ/4 stepped impedance resonators

• Published in: Electronics letters Vol. 50; no. 3; pp. 192 - 194
• Main Authors: Zhang, Songbai, Zhu, Lei
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 30.01.2014; Institution of Engineering and Technology
• Subjects: Applied sciences; Bandpass filters; band‐pass filters; Circuit properties; DB‐BPF; dual‐band λ‐4 SIR; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Filtering; Filtration; finite transmission zero; fourth‐order fully canonical dual‐band bandpass filter; fourth‐order microstrip DB‐BPF; frequency 1.8 GHz; frequency 5.8 GHz; Frequency filters; Impedance; inverter; Inverters; invertors; Mathematical analysis; microstrip filters; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; microwave filters; Microwave technology; resonator filters; Resonators; Stepped; UHF filters; λ‐4 stepped impedance resonator; resonator filters; frequency 1.8 GHz; microstrip filters; fourth-order fully canonical dual-band bandpass filter; DB-BPF; dual-band λ-4 SIR; inverter; finite transmission zero; UHF filters; λ-4 stepped impedance resonator; invertors; band-pass filters; microwave filters; fourth-order microstrip DB-BPF; frequency 5.8 GHz; GHz range; Quarter wave plate; Impedance converter; Stepped impedance device; Band pass filter; Passband; Microwave filter; Quarter wave line; Microstrip; Multiple frequency; Transmission zero
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2013.3101

A fourth-order fully canonical dual-band bandpass filter (DB-BPF) using λ/4 stepped impedance resonators (SIRs) is presented. In the mainline path, four dual-band λ/4 SIRs are serially coupled by alternative J and K inverters, and cross-couplings, K14 and JSL, are analytically introduced to achieve two pairs of finite transmission zeros at both sides of each passband. To experimentally demonstrate this attractive fully canonical dual-passband filtering performance, a fourth-order microstrip DB-BPF centring at 1.8 and 5.8 GHz with two pairs of finite transmission zeros for each passband is synthesised and fabricated.