Grating diplexer using dielectric waveguides for millimeter wavelengths

A new grating diplexer using dielectric waveguides is proposed for millimeter-wave applications. It consists of two symmetric rectangular dielectric waveguides in which two 3-dB hybrids and two gratings for band-stop filters are contained. Hence, it is convenient for integration. In the analysis of grating structures, we introduce equivalent circuits to which F, S, and T matrices are applied to obtain the dispersion properties and the frequency characteristics of reflection and transmission. Experimental data obtained at millimeter-wave frequencies agree well with theoretical values. It is found that millimeter-wave grating diplexers can be used as bandsplitting diplexers and channel diplexers in millimeter-wave communication equipment.