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Design of compact dual‐band bandpass filters using λ/2 and combined λ/4 stepped‐impedance resonators
Author(s) -
Lee ChingHer,
Hsieh YiHuan,
Ho MinHua
Publication year - 2007
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.22823
Subject(s) - stopband , resonator , passband , band pass filter , multi band device , microwave , electrical impedance , attenuation , coupling (piping) , physics , equivalent circuit , filter (signal processing) , acoustics , electronic engineering , electrical engineering , engineering , topology (electrical circuits) , optics , telecommunications , mechanical engineering , voltage , antenna (radio)
This paper presents a compact dual‐band bandpass filter (BPF) that consists of a pair of L‐shape half‐wavelength (λ/2) stepped‐impedance resonators (SIRs) and an inverted Z‐shape resonator. The latter is actually a combined structure of two λ/4 SIRs along with a magnetic coupling in between and hence designed to reduce the circuit size. Cross‐coupled SIR configuration and 0° tapped‐feed structures are adopted to introduce attenuation poles around the passband edges for selectivity improvement. A wider −20‐dB upper stopband is achieved by properly separating the third resonant frequencies of the SIRs of different types. The newly designed dual‐band BPF was verified by circuit implementation, and a very good agreement between the simulated and measured results was observed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2703–2706, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22823