이중 구리선을 이용한 THz 도파관의 전파특성

Abstract

In this paper, we have described the various characteristics of the two-wire transmission lines. The lines consist of two 0.4mm (or 0.5mm) diameter copper wires with centers separated by 1.0mm. Scattering coupling is generally used in order to combine the THz wave with two-wire lines in the previous study. Instead of this method, we have used two tungsten probes with 1 μm diameter tips in near-contact with the pulse generating and receiving antennas. It can improve the coupling efficiency because the dipole antenna radiation pattern is similar to the propagation mode on two-wire transmission lines. We have made the waveguide holder with wide bandwidth, high efficiency by Teflon disk experiments of various forms. But, the remaining serious practical problem is how to support the wires and

how to maintain their separation without disturbing the TEM mode propagation for long distance. To solve this problem, we have fabricated the two-wire lines using Teflon tube. The 150 μm thick Teflon covered two-wire lines are prepared by removing the two original stranded wires separated by 1.0 mm between the wire centers from the commercial Teflon covered two-wire lines and replacing them with the same solid Cu wire used in the air spaced two-wire lines. A single wire waveguide have high attenuation when the waveguide were curved, and Parallel-plate waveguide has the drawback of bending setup. Unlike other waveguide, two-wire waveguide has the advantage of bending experimental configuration with low attenuation. We also investigate the bend characteristics of two-wire waveguide.