Research On Heterostructure SSPPs Transmission Properties

The surface plasmon polaritons (SPPs) is a special surface wave with good constraint force of electrical field. In the microwave band, metal shows properties of ideal conductor, resulting a poor capability for the field in the electromagnetic wave propagation process. Thus the spoof surface plasmon polaritons (SSPPs) are put forward to solve this problem. In fact, SSPPs are a kind of surface electromagnetic wave which propagate along the periodic structure of metal surface (grooves, holes or slit).Recently,due to the excellent transmission characteristics, SSPPs have been paid attention by many researchers, most of which focus on the units with single structure, however few studies have been done on composite structures.Therefore, in this paper, a deep research on the transmission characteristics of composite SSPPs structure and its application are conducted.Firstly, the possibilities of getting connected and transmitted by SSPPs transmission lines with different cell structures have been discussed. Symmetrical SSPPs transmission lines of different structural forms have been studied, and the propagation characteristics of the symmetrical structures with asymmetric structures, asymmetric structures with asymmetric structures have been investigated.The results of numerical simulation show that the transmission coefficient of composite structure has a significant decrease compared with the transmission line formed by the same unit structure alone, when the symmetrical structure is connected to the asymmetric SSPPs transmission line. The reason for this results is the existence of energy loss during the mode transition process and the radiation transmission. In addition, when the transmission lines with similar symmetry or similar asymmetric transmission lines are connected to each other as long as the unit dispersion curve tends to be consistent of the two transmission lines, it can also maintain the original SSPPs wave propagation even if the unit structure is different, and the transmission process has the characteristics of extremely wide bandwidth and excellent performance.In addition, in the SSPPs cycle unit structure, we combine the SSPPs units of different configurations in the same cycle to form a SSPPs transmission line with composite structures. Through the dispersion curve analysis, full wave numerical simulation and experimental measurement, it is found that the transmission line structure has the transmission band gap similar to the photonic crystal, and can be used as a band rejection filter. When changing the geometric parameters of the cell structure, the effective adjustment of the frequency and bandwidth of the stopband can be realized.