A compact wideband bandpass filter using single asymmetric SIR with low loss and high selectivity

Abstract

AbstractIn this letter, a novel compact wideband bandpass filter (BPF) using single asymmetric stepped‐impedance resonator with one‐step discontinuity is designed and fabricated. The first two resonant modes of the asymmetric SIR are coupled together and applied to create a wide passband. The proposed filter at center frequency f0 of 4.2 GHz has very good measured characteristics including the bandwidth of 2.9–5.05 GHz (3‐dB fractional bandwidth of 52%), average low insertion loss of 0.2 dB, and sharp rejection of 53 and 88 dB/GHz in lower and higher passband edges. Additionally, the wideband BPF has a smaller circuit size in comparison of previous works. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 242–244, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24023