Fig. 1. Drawing system of waveguide tube. (a) Schematic diagram of the system; (b) picture of the system

Fig. 2. GTMW and CBMW. (a) Schematic diagram of GTMW and CBMW; (b) picture of GTMW sample^[20]

Fig. 3. Waveguide transmission characteristics and imaging test system

Fig. 4. Measured results of bending loss characteristic of different waveguides at a frequency of 0.3 THz^[20]

Fig. 5. Cross-section diagram of HEW and mode field diagrams of TE_11X, TE_11Y and TE_21Y modes

Fig. 6. Mode and loss characteristics of HEW^[47]. (a) (b) Relationship between the normalized cutoff wavelength λ_NC and the ellipticity of the waveguide; (c) relationship between the structural parameters of HEW and the loss at 0.1 THz; (d) loss characteristic for three lowest order modes of 1.5/2.7-HEW

Fig. 7. Loss and polarization of the output light of 1.5/2.7-HEW in the case of bending and twisting^[47]. (a) Bending case; (b) twisting case

Fig. 8. Relationship between structural parameters of HEW and waveguide loss at 150 GHz

Fig. 9. Loss of dielectric metal film waveguides with different dielectric film thicknesses under different bending angles at 4.3 THz^[79]

Fig. 10. Blade imaging results^[20]. (a) Picture of the blade; (b) scanning image by 0.3 THz

Fig. 11. Schematic diagram of THz high frequency transmission system^[80]

Fig. 12. Transmission loss characteristic of waveguide in W band^[81]