Triple-Mode Substrate Integrated Coaxial Resonator Based Bandpass Filter Featuring Flexible Transmission Zeros and Adjustable Bandwidth

• Published in: IEEE transactions on circuits and systems. II, Express briefs Express briefs, 2021-04, Vol.68 (4), p.1223-1227
• Main Authors: Krishna, Idury Satya, Mukherjee, Soumava
• Format: Article
• Language: English
• Subjects: adjustable bandwidth; Band-pass filters; Bandpass filters; Bandwidth; Bandwidths; Cavity resonators; compact; Filtering theory; flexible transmission zeros; Form factors; Insertion loss; Integrated circuit modeling; Mathematical model; Metal strips; Rejection; Selectivity; Strips; Substrate integrated coaxial resonator (SICR); Substrate integrated waveguides; Substrates; Topology
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2020.3035717

This communication presents substrate integrated coaxial resonator (SICR) based triple-mode bandpass filters designed for K_{u} -band. A self-shielded SICR based third-order filter is realized using two planar coaxial resonators (SICR) embedded in a substrate integrated waveguide cavity (SIW). Merging the TEM based mode of two SICR's with TE 101 mode of SIW significantly enhances the bandwidth in a compact size. A novel topology realized using short circuited metallic via connecting to the top conducting plane through a metal strip demonstrates high degree of flexibility in positioning the transmission zeros to improve the selectivity as well as extend the out-of-band rejection of proposed filter. The three experimental prototypes devised for K_{u} -band with fractional bandwidth more than 23% demonstrate multiple transmission zeros for good selectivity and out-of-band rejection with low insertion loss in a compact form factor.