Design of dual-band bandpass filter using stepped impedance resonator and defected ground structure

✍ Scribed by Wu-Nan Chen; Wei-Kuo Chia; Cheng-Fu Yang; Chih-Liang Shih

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 503 KB
• Volume: 49
• Category: Article
• ISSN: 0895-2477
• DOI: 10.1002/mop.22933

✦ Synopsis

Abstract

This article presents a novel microstrip dual‐band bandpass filter (BPF) comprising a symmetrically‐bent, open‐loop, square‐ring stepped impedance resonator (SIR) on the upper surface and a symmetrical U‐shaped defected ground structure (DGS) on the lower metallic ground plane. A center frequency of 2.45 GHz is obtained for the first passband of the BPF by adjusting the dimensions of the SIR, while a center frequency ranging from 5 to 7 GHz is obtained for the second passband by adjusting the dimensions of the DGS unit. The experimental and simulation results demonstrate that the insertion losses of the BPF are −1.4 dB at 2.45 GHz, −1.3 dB at 5.75 GHz, and −4.1 dB at 5.2 GHz. The characteristics of the proposed BPF with and without the DGS unit are compared, and the dependency of the second resonance frequency on the dimensions of the DGS unit is discussed. Finally, the effectiveness of etching an additional DGS unit beneath the feed lines to suppress the high out‐of‐band harmonic frequencies is also demonstrated. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 3099–3103, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22933