Enhancement of the detection of THz Sommerfeld wave using a conical wire waveguide

In this study, the coupling properties of a conical copper wire waveguide were investigated in the terahertz (THz) frequency range using theoretical simulations and experiments. Because a conical wire tip has a smaller tip diameter than a cylindrical wire tip, it has a greater THz field density than a cylindrical wire tip. The measured THz pulse increased 4.5 times upon contact with the 30 microm-diameter conical wire tip compared with the THz pulse when a 500 microm-diameter cylindrical wire tip was used. This result agrees well with that of theoretical simulations such as high-frequency structure simulation (HFSS), which is based on the finite element method.