Research Of Low-loss Hollow Metal Terahertz Waveguide

Terahertz (THz) electromagnetic wave has broad application prospects on chemical and biological detection, environment detection, object imaging, military security, mobile communications and other fields. At present, because of lack of waveguide of low loss and low dispersion, its application is limited. Research and development of low-loss terahertz waveguide is of great significance for promoting the application of terahertz technology. In this paper, study the low-loss hollow metal terahertz waveguide. Analyze the transmission characteristics of parallel metal waveguide and hollow metal waveguide. The structure of the waveguide was improved by plated film on the waveguide, in order to reduce the transmission loss of terahertz wave. Measure the loss of hollow waveguide with metal film by continuous terahertz wave system in this paper.The propagation loss of terahertz electromagnetic waves in metal hollow waveguides mainly originates from the loss of metal interface reflection. In this paper, first, research the method to reduce the loss of metal interface. By coating dielectric film on metal interface, the loss of TM wave can be reduced effectively. Numerical analysis the reflectivity of the metal before and after plated dielectric film. Discuss the reflectivity of terahertz wave when metal is plated different materials, and find the maximum reflectance when the Polyethylene film is0.06mm. The transmission loss is reduced for the parallel metal waveguides plated dielectric film when the waveguide layer is thicker than0.8mm, compared with metal waveguides.Secondly, calculate and analyze the permittivity of metal in elementary electronic theory. Analyze transmission mode of hollow terahertz waveguide by calculating cut-off frequency, and TE11mode is the main mode. By analyzing the loss of hollow waveguide plated different metal film in theory, choose low-loss material. Calculate and analyses the transmission loss when the mode of the waveguide is different, and the loss of TE01is minimal. Compared with hollow waveguide of quartz, the loss reduces1.44dB/cm.Finally, prepare of hollow waveguide with metal film by silver mirror reaction and measure the loss of hollow waveguide with metal film by continuous terahertz wave system. The backward wave oscillator (BWO) is the source of terahertz wave system. Hollow waveguide is measured by the method of truncation and comparison, and the measured loss is0.989dB/cm.In this paper, analysis of transmission characteristics of parallel metal waveguide and the hollow metal waveguide in theory, and measure the loss of hollow waveguide with metal film by continuous terahertz wave system. The purpose is to find out low loss, easy preparation, simple structure, low cost of the terahertz waveguide, and promote the application of terahertz.