Design of 0-dB forward coupler using half-mode groove waveguide for wireless power transmission

This paper proposes a 0-dB forward coupler consisting of the half-mode groove waveguides for wireless power transmission. The half-mode groove waveguide is equivalent to the groove waveguide of LSM mode, where the electric wall is assumed on the symmetrical plane. Though this structure occupies only half of the groove waveguide, it has the same property as the groove waveguide. In this paper, the transverse resonance technique and the mode matching method are applied to derive the even- and odd-modes phase constants. Then, a 0-dB forward coupler including bend sections is designed at 24GHz and the S-parameters are calculated. In addition, a dielectric strip is inserted to increase the spacing between the two guides. The validity of the design results is confirmed using em-simulator (HFSS).