Performance Analysis of Waveguide BPF Loaded with Dielectric Frequency Selective Structure

The performance analysis of waveguide bandpass filter (BPF) loaded with dielectric frequency selective surface is presented. The proposed filter is constructed by use of a rectangular waveguide encapsulates 2 layers of FR4 epoxy dielectric substrate which are flanking rectangular strip lines yielding a dielectric frequency selective structure. A WR284 type rectangular waveguide designed to work on the TE10 mode is employed for the filter implementation. The performance of filter focused on its bandwidth response and $S$-parameters, i.e. $S_{11}$ and $S_{21}$, is analyzed through simulation by investigating the parameters of rectangular strip lines such as the length of strip line, the separation between strip lines, and the number of strip lines. As an experimental characterization, a waveguide BPF is realized with a dielectric frequency selective structure comprising 3 rectangular strip lines resulting in the filter performance comparable to the design result.