Fig. 1. Schematic of infinite-length PPWG

Fig. 2. Three-dimensional structure of finite-length PPWG

Fig. 3. Field distribution in three-dimensional numerical simulation. (a) Field distribution of cos-Gaussian beam propagating in finite-length PPWG at frequency of 0.35 THz; (b) electric-field intensity distribution of cross-sections at different propagating distances

Fig. 4. Analysis results of amplitude and phase. (a) Normalized electric-field intensity distribution in x direction for y=0 at different z values; (b) RMSE between theoretical and simulated results; (c) phase distribution of electric field in x direction for y=0 at different z values; (d) comparison between theoretical and simulated results of phase distribution in z-axis