Title :
Microstrip spiral-coupled scheme bandpass filters with mutual electric and magnetic coupling
Author :
Xun Luo ; Sheng Sun ; Er-Ping Li
Author_Institution :
Huawei Technol. Co., Ltd., Shenzhen, China
fDate :
Oct. 29 2012-Nov. 1 2012
Abstract :
This paper presents miniaturized microstrip bandpass filters based on the quarter-wavelength (λ/4) spiral-coupled scheme (SCS). By introducing the mutual electric and magnetic coupling between two SCS, two resonant modes can be well adjusted to form a passband and four transmission zeros can be generated to obtain a good out-of-band rejection. Without modifying the initial design parameters, another transmission zero with strong attenuation can be further introduced by loading a parallel-coupled line section along the symmetrical plane, thus largely widening the upper stopband. To verify our proposal, two filters are finally implemented and fabricated, which exhibit the following attractive features: low insertion loss, good passband selectivity, wide stopband with a high rejection level, and compact size.
Keywords :
band-pass filters; microstrip filters; λ/4 SCS; electric coupling; magnetic coupling; microstrip spiral-coupled scheme bandpass filters; parallel-coupled line section; quarter-wavelength spiral-coupled scheme; resonant modes; Band pass filters; Couplings; Filtering theory; Magnetic resonance; Microstrip; Microwave filters; Passband; Bandpass filter; dual-mode; mutual electric and magnetic coupling; parallel-coupled line; spiral-coupled scheme (SCS);
Conference_Titel :
Microwave Conference (EuMC), 2012 42nd European
Conference_Location :
Amsterdam
Print_ISBN :
978-1-4673-2215-7
Electronic_ISBN :
978-2-87487-026-2