Analysis of coupled-trough-waveguide based on E-plane planar circuit approach

In this paper, the trough-waveguide consisting of metallic plates is treated as an E-plane planar circuit that has discontinuities only in the E-plane. The coupled-trough-waveguide is composed from two trough-waveguides arranged symmetrically. The E-plane planar circuit approach combined with the transverse resonance technique is applied to derive the phase constants of even- and odd-modes. The coupled power as a function of distance is calculated using the phase constants, and by adjusting the coupling length to achieve 100% coupling, a 0-dB forward coupler is designed at 5.8GHz. The validity of the analytical and design results is confirmed by using em-simulator (HFSS).