Design And Research Of Microwave Device Based On Spoof Surface Plasmon Polaritons With Planar Structure

Surface plasmon polaritons(SPPs)are electromagnetic excitations propagating at the interface between a dielectric and metal,evanescently confined in the perpendicular direction.It has extensive research and applications in the optical frequencies.As an important derivative of SPPs in the optical frequencies,spoof SPPs have attracted the attention of many scholars because of their excellent features in microwave and terahertz frequencies.Because of the unique dispersion characteristics and field distribution characteristics,spoof SPPs are very different from the traditional microwave structure in the microwave frequencies.There are two types of spoof SPPs structures.One is three-dimensional spoof SPPs structure.Its process is very complicated and difficult and it is hard to be connected to two-dimensional microwave components.But the two-dimensional planar spoof SPPs structure can meet the requirement.It is significance to study the two-dimensional planar spoof SPPs structure,and apply it to design microwave devices.The specific topics of this thesis are as follows:Firstly,we use the mode expansion method to analyze the dispersion characteristics of drilled grooves and holes in metal surface.We introduce several numerical methods that commonly used.The subwavelength constraint and transmission loss of structure are analyzed.And we also introduce some excitation modes in the thesis.Secondly,based on the above theory basis,we analyze the parameter size and dispersion of spoof SPPs structure that drilled rectangle holes in the metal surface.And the impact of different parameter size on the dispersion curve and cutoff frequency are analyzed.Based on this structure,we design the narrow band pass filter,and it has lower transmission loss and higher transmission efficiency in the pass band.Based on this structure,we also design the filter with dual notched band,and these notched band can avoid interference with the WLAN and satellite communications in the UWB frequency spectrum.Thirdly,based on the above theory basis and the inspired by filter design.We proposed a new spoof SPPs structure that drilled circular holes in the metal surface.The dispersion characteristics and transmission characteristics of structure are analyzed.Based on this structure,we design the microwave power divider,and the device has good power allocation performance and transmission performance.