Reduction of radiation losses of the single-wire waveguide at THz frequencies

Summary fom only given. In the last years, many experiments have shown that the single wire waveguide (SWW) is able to guide wide-band THz signals with very low attenuation and negligible dispersion. However, since energy is not transversally bounded, when the wire is bent, strong radiation losses take place. This drawback really limits the practical use of this interesting waveguide. To reduce the radiation on bends one can add a dielectric coating or use a small wire radius, getting better results when both options are combined. Nevertheless, in those cases, the propagation losses of the waveguide become very high and it is no longer a good option for THz waveguiding. In this work it is proposed the use of transitions between a SWW of large radius and proposed the signal shows the dielectric coated single wire waveguide (DCSWW) of small radius. The structure, allows along straight paths and a transmission losses of the to combine both, a low-loss waveguide to guide waveguide with reduced radiation losses. structure vs. the transition length. When only the radius is reduced, 9.5dB are obtained for the best case, whereas when also a coating is present, minimum of losses decrease to 5.5dB. There is a large gain compared to the losses of a bend implemented with a SWW of large radius (22dB for a 100μm radius wire). Electric field on the bend is shown in the bottom for the three commented options.