Design and optimization of terahertz directional coupler based on hybrid-cladding hollow waveguide with low confinement loss*
Yu Ying-Ying†, Li Xu-You, Sun Bo, He Kun-Peng
       
Dependences of confinement loss on the frequency for 0.20-mm-, 0.25-mm-, 0.30-mm-, 0.35-mm-, and 0.40-mm-thick metallic layers, with the inset showing the relations between the frequency and confinement loss for 0.30-mm-, 0.35-mm-, and 0.40-mm-thick metallic layers.