Flexible low-loss dielectric/metallic coated hollow waveguide for 3.17 THz wave transmission

A flexible low-loss dielectric/metallic hollow waveguide for high-frequency terahertz transmission was analyzed, fabricated, and characterized. Firstly, dielectric material absorption was taken into consideration to optimize the dielectric film thickness. The optimal thickness becomes smaller after considering dielectric absorption. Silver was selected as the metallic layer owing to its lower attenuation for high-frequency terahertz wave as well as a simple fabrication technique. Waveguides were fabricated through wet chemistry method and a configured dynamical liquid-phase coating system. Waveguide samples with different inner diameters and dielectric thicknesses were prepared and characterized by using terahertz free electron laser. The transmission loss was 1.3 dB/m at 3.17 THz for the waveguide with 8 mu m-thick dielectric film and 2.5 mm inner diameter. And the losses were less than 2 dB/m even when it was bent to the angle of 180 degrees. The waveguides also showed losses less than 3 dB/m at both 2.68, and 1.86 THz frequencies.