Microwave Passive Dessive Based On Spoof Surface Plasmon Polaritons

With the development of Spoof Surface Plasmon Polaritons(SSPP),the research and application of Surface Plasmon Polaritons(SPP)has gradually expanded to the microwave and terahertz frequency range.SSPP has the distinct advantages of low loss and small size in Microwave device designs.Therefore,their applications in passive components design and Antennas have become a current hot area of research.This paper presents the design of a novel Band-Stop filter,Band-Pass filter and a Branch Line Bridge.The design topology is based on the comb-type and fish-bone SSPP.The performance of the design was analyzed through simulations and measurements.A brief detail of the work is given below;1.Design of bandstop filter based on comb SSPP transmission line.Firstly,The equivalent circuit of comb SSPP and its dispersion characteristics are analyzed.Secondly,The band stop filter is designed by loading an open stub on the basis of cascaded comb type SSPP.The results of CST simulation and physical measurement show that the dispersion characteristic of SSPP depends on the size of the structure i.e.by controlling the size of the structure,we can achieve the required performance parameters in the desired frequency band.The band-stop filter combined with open stub and comb-type SSPP has the advantages of small size and simple structure.2.The broadband bandpass filter is designed by using double side comb type SSPP.By combining the coplanar waveguide,the impedance transition section and the periodic SSPP loading the stub,a fourth-order single-passband filter and a second-order dual-passband filter are designed.Compared with the single-sided SSPP bandpass filter,the double-pass comb type SSPP structure of the bandpass filter not only has a wide bandwidth,high suppression,but also has low radiation loss.3.The branch line bridge was designed by using double-sided fishbone SSPP and comb SSPP in tandem.The impedance transition section with four ports is designed by using the fishbone type SSPP,and the bridge arm of the branch line bridge is formed by connecting the four comb SSPP transmission lines to each other,thus realizing the 3dB output of the straight and coupling port.The new branch bridge has the advantages of strong coupling and high bandwidth utilization.