Wideband bandpass filter of folded substrate-integrated waveguide integrating with stripline compact resonant cell

A wideband bandpass filter constructed into folded substrate-integrated waveguide (FSIW) is proposed, incorporating with the stripline compact resonant cell (CRC). The folded SIW preserves nearly the same propagation characteristics with its counterpart substrate-integrated waveguide (SIW); however, the width of FSIW is only half of SIW, providing a more compact platform for many novel circuits or subsystems. A prototype of this wideband bandpass filter was fabricated and measured. Good agreements are observed between the experimental results and the simulations. The results demonstrate a wide passband about 83.7% (from 3.3 to 8.05 GHz) at −10 dB return loss and the insertion loss in the entire passband is less than 0.26 dB. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 390–393, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23117