制作了具有不同介质膜厚度的大口径柔性介质金属膜波导, 测试了金属膜波导和介质金属膜波导在G波段、4.3 THz和中远红外等频段的传输特性.结果表明, 波导的传输损耗在G波段随介质膜厚的增加而增加, 孔径2.6 mm的金属膜波导在160 GHz传输损耗为2.1 dB/m且在G波段波导的传输损耗对弯曲不敏感.在4.3 THZ频点波导的传输损耗随介质膜厚的增加而减小, 镀制介质膜可以大幅减小波导的传输损耗以及弯曲附加损耗, 孔径3.6 mm介质膜厚为1.2 μm的介质金属膜波导的传输损耗为2.84 dB/m.光斑能量则随介质膜厚的增加更加集中于低阶传输模式.

Big-bore and flexible dielectric-coated metallic waveguides were fabricated with various dielectric film thicknesses. Transmission characteristics were measured for the metallic waveguides and dielectric-coated metallic waveguides in G band, 4.3 THz, and mid-infrared regions. Measured results show that waveguide loss in G band increases with the increase of dielectric film thickness. Loss for the 2.6 mm-bore metallic waveguide is 2.1 dB/m at the frequency of 160 GHz and the additional loss caused by bending for the waveguide is small. Waveguide loss at 4.3 THz decreases with the increase of dielectric film thickness. And the additional loss caused by bending for the dielectric-coated metallic waveguide decreases with the increase of dielectric film thickness. Loss for the 3.6 mm-bore dielectric-coated metallic waveguide with 1.2 μm dielectric film thickness is 2.84 dB/m. Measured beam profiles show that energy is more concentrated in the low-order transmission mode as the film thickness increases.