Low‐Loss Flexible Terahertz Metal‐Inner‐Coated Corrugated Fiber Waveguide

In this paper, we propose a flexible metal‐inner‐coated corrugated fiber waveguide to achieve low‐loss transmission of terahertz (THz) waves in the frequency range of 140−290 GHz. We design flexible metal‐coated, inner‐coated corrugated fiber waveguides using both analytical and numerical methods. This work investigates the effects of structural parameters, including corrugation depth, corrugation period, groove width, and core radius, on transmission performance, which could be applied for further waveguide designs for performance optimization and other frequency bands. From the results, the proposed waveguide provides propagation losses of 0.028−0.075 dB/m within the 140−290 GHz, leading to a remarkable 70% reduction compared to the metallic‐inner‐coated waveguides with smooth interior surface and the same core radius. The absolute values of group velocity dispersion are below 0.28 ps/GHz/m. Moreover, numerical calculations show that, for the proposed flexible metal‐inner‐coated corrugated fiber waveguide with a core radius of 4 mm, the bending loss is 0.1023 dB/m at 185 GHz under a bending radius of 20 cm. The proposed metal‐inner‐coated corrugated fiber waveguide features extreme low‐loss, flexibility, and compactness, indicating tremendous potential for the interconnection between THz devices.