Fabrication of low-loss polycarbonate tube waveguide for broadband terahertz transmission by controlled polymer solution-coating method

A controllable polymer solution-coating method was used to fabricate polycarbonate (PC) tube waveguide with broadband terahertz (THz) transmission capability. Highly uniform 3-mm-bore PC tube waveguides with three different wall thicknesses of 30.0μm, 57.0μm and 80.0μm were prepared. The measured transmission bandwidths are 1.4 THz, 1.7 THz and 1.9 THz, respectively. The lowest transmission loss of the waveguide sample with 80μm wall thickness is 0.15 dB/cm at 1.0 THz. A metal/dielectric hollow THz waveguide based on PC dielectric tube was also fabricated in this study. The transmission loss of the silver/PC hollow waveguide is 0.13 dB/cm at 300 GHz. It is expected to be decreased to 0.007 dB/cm by further optimization of the PC tube wall thickness.