Spoof plasmonic waveguide of a roofed metallic grating for terahertz applications

Plasmonics has become a flourishing research field from optic to lower terahertz (THz) and microwave frequency band. The extreme intense near field of spoof surface plasmons (SSP) on the corrugated metal surface makes it attractive to develop novel electronic sources and many other compact devices in THz regime. In this paper, we propose and investigate a new spoof plasmonic waveguide composed of roofed metallic grating both theoretically and numerically. The theoretical result is verified by numerical simulation of finite integration method both for 2-D and 3-D structure and good agreement is realized. Dispersion and propagation losses of SSP mode on this structure with various structures are also studied and analyzed at THz frequencies (the real copper is used). We find that the roofed metal plate can make profound influence on SSP dispersion characteristics and propagation losses compared with that of opened structure thus should be considered carefully for practical applications. Decreasing the location of top metal plate can induce larger propagation losses of bound SSP mode. Other parameters are similar with that of opened grating which are also considered in the presence of roofed metallic plate. Our complete studies of this roofed metallic grating pave the way for a variety of potential applications such as low-loss waveguide, compact filters, high-efficiency antenna and efficient electronic sources in THz regime.