Transmission Characteristics Of Spoof Plasmon Material Assisted Waveguide

Surface Plasmon Polaritons (SPPs) is the charge density oscillation excited by the coupling electromagnetic field at the metal/dielectric interface. In the microwave regime, periodically corrugated grooves called spoof surface plasmon material (SSPM) are designed by researchers, which generate spoof surface wave similar to surface plasmon polaritons. Such discovery of SSPM provides researchers new perspective and idea to electromagnetic wave manipulation.In this paper we studied the transmission characteristics of metal-dielectric planar waveguide as well as metal-dielectric-metal planar waveguide based on the theory of electromagnetic wave propagation. The electromagnetic characteristics of such two dielectric waveguides are analyzed theoretically. The dispersion relations considering plasmon condition are also derived and analyzed.To explore the possibility of plasmon materials applying in parallel plate waveguide (PPW), we design a PPW assisted by monolayer plasmon material. The corresponding theoretical expressions of field intensity and dispersion are deduced in detail, with which we perform and simulate the transmission characteristics of the proposed PPW. From the double angles of theory and experiment, we find some characteristics of PPW assisted by plasmon. The results of research shows that the proposed PPW possess a bandstop property. Furthermore, the upper cutoff frequency equals to the resonant frequency of plasmon, while the lower cutoff frequency is controlled by the thickness of plasmon layer. Concretely, the thicker plasmon layer leads to a smaller lower cutoff frequency and wider bandstop. However, the width of bandstop won’t vary any more once the thickness of plasmon layer reaches its critical value. There are two kinds of physical mechanisms existing simultaneously in the bandstop:one stems from resonant coupling between plasmon and medium, the other relates with the generation of the surface waves. In addition, we also study the influence of plasmon frequency and collision frequency on the transmission characteristics. The filter function of the proposed PPW is tunable by changing the plasmon frequency flexibly.In allusion to the sensing application, the plasmon layer is replaced by a periodic rectangular corrugated metal materials (PRCMM). The results of simulation show that the cutoff frequency varies with the changing of permittivity of filling materials. The proposed PPW is able to distinguish clearly the different filling materials via analyzing the changing of cutoff frequency. The simulation results show that while the permittivity changes 0.1%, the average cutoff frequency changes 1.8GHz. Such results imply the high quality sensing characteristics of SSPM waveguider, and new direction for the application and development of SSPM.