Research On The Scattering And Transmission Characteristics Of Spoof Surface Plasmons Stuctures

Surface plasmons polaritions(SPPs)propagating along the direction of the interface between metal and dielectric is a kind of electron dense wave excited by light on metal surface,which is a mixture of free electrons and incident photons.Unlike in the optical frequency band,at microwave or terahertz band,metals are generally regarded as perfect electric conductor,thus do not support the SPPs wave.Spoof Surface plasmons polaritions(SSPPs)which is confined by periodic structures,such as sub-wavelength grooves or holes in the metal surface behave like SPPs.This kind of metal engraved with periodic grooves is usually referred to as SSPPs structure.In this thesis,the scattering and transmission characteristics of SSPPs-structures in time and frequency domain are studied,which are in the following aspects:Firstly,a periodic structure of square ring aperture array is studied in this thesis.Started from the scattering characteristics in frequency domain,the structure of square ring aperture array can be used to reduce radar cross section(RCS)of objects and enhanced the electromagnetic stealth performance.Meanwhile,the time domain electromagnetic effect from the low frequency domain RCS periodic structure of square ring aperture array is given.The effect is that the scattering wave has large amplitude at the beginning and becomes smaller after a period of time when in the stable state.This work provides a new way to improve radar anti-stealth technology.The mechanism of the frequency and time domain backward scattering are explained and verified by the equivalent circuit method.Secondly,a compact periodic structure of T-shaped slot is designed in this thesis.The effects of geometrical dimensions on the dispersion curves are studied.Compared with the traditional trapezoidal and rectangular groove,the results show that the proposed structure is miniaturized and effective for confining SSPPs.Meanwhile,SSPPs waveguide based on the T-shaped slot structure is designed and proposed to support SSPPs wave by using the coplanar waveguide(CPW)as the feed and smooth matching converter between the CPW and the SSPPs waveguide.By simulating the electric field distribution of the T-shaped slot structure,the traditional trapezoid and the rectangular groove structure,it is verified that the proposed periodic structure has stronger field confine ability to SSPPs wave.Then,the SSPPs waveguide samples were fabricated and measured.The last results are in good agreement with the simulation results.In addition,an X-shaped slot SSPPs waveguide is proposed.It can also propagate the microwave signals effectively.