A band-pass filter using via-hole-wall cavity

Abstract

In this paper, we presented a band-pass filter-consisting of a post-wall cavity, resonator. This band-pass filter was fabricated in a two-layered printed circuit board, which includes an input and an output substrate integrated waveguides as the feeding structures in the top layer and a cavity in the bottom layer. The interconnection of the signal between different layers is achieved via the apertures etched on the input and output waveguides and cavity. We found the bandwidth of such a class of band-pass filter could be altered by tuning the length of the coupling apertures. Besides, the pass-band frequency can be estimated by the resonant frequencies of the cavity. We have fabricated the bandpass filter on a low-loss dielectric substrate and measured its S-parameters, including the return- and insertion-loss. In addition, the numerical simulation by the CST microwave studio, a full-wave time-domain numerical method, was also carried out. A good agreement between the measured and simulation results was obtained. (c) 2007 Wiley Periodicals, Inc.