Single-wire transmission lines at terahertz frequencies

In this paper, we report results on an original way to excite surface waves on a single-wire transmission line. Although these waves were proposed many decades ago by Goubau, the novelty of our structures is to achieve a broadband planar excitement. This configuration is very well suited for the terahertz frequency range and allows the investigation of biological entities with high spatial resolution with the use of novel biomicroelectromechanical systems, which include microfluidic functions. From experimental results, we compare different types of transitions from coplanar waveguides, and different substrates are also used. We show that the excitation is highly efficient and broadband for structures on a quartz substrate