Investigation on low-loss metallic terahertz waveguide with coating

Studied on the transmission of terahertz wave in the metallic parallel plate waveguide coated by film, and finally found that transmission losses was less in the TM mode when the gap of plates was more wider. Analyzed the size of waveguide, the thickness and refractive index of film by the ray-optics method,and have got the optimal structural parameters with the lowest loss. Calculated and analyzed the loss of waveguide which had caoting or not by the transfer matrix. When polyethylene is 0.06 mm, the loss of waveguide was more lower. It's a great significance for the development of terahertz device and waveguide.