Dielectric-grating band-pass filters

The performance and bandpass characteristic of open dielectric waveguide resonators are analyzed theoretically, considering an infinite periodic (along the y-axis) grating of parallel ideally conducting identical rectangular bars separated by dielectric waveguide channels. The structure is symmetric with respect to the xy-plane and the height of the bars is fixed. The width of the dielectric channels is fixed, but their height and the dielectric material are controllable. Calculations are made for a horizontal grating excited from above by a plane monochromatic wave with an H-vector only parallel to the conductors and propagating at an arbitrary angle to the vertical z-axis. The corresponding diffraction problem is solved for the Fourier series coefficients characterizing the scattered field and for the amplitude-frequency characteristic of the grating.