The Scattering Characteristics Of Moving Periodic Medium

So far, people has already performed some deep research on moving medium and periodic structure, and put the results into application in many areas. But moving periodic medium structure is still a very novel issue and seldom research results have been published. The research on moving periodic medium will enrich microwave electromagnetic theory, and have a far-reaching impact in the related fields.In this paper, the scattering characteristics of moving conductor-dielectric periodic (MCDP) structure are studied under the guidance of the instructor. Firstly in accordance with the references, the derivation about Lorentz transformation, Minkowski constitutive relations of moving isotropic medium, Galilean transformation and the boundary conditions of stationary and moving boundaries is introduced. On this basis, according to the boundary conditions, the cases of reflection and transmission on stationary and moving boundaries are analyzed. Then, from periodic structure and its characteristic, Floquet mode function in moving periodic medium is studied, and it can be seen that the function is different from Floquet mode function in stationary periodic medium, expressed as the combination of spatial and temporal harmonic. It has the orthogonality in a spatial period and a temporal period respectively, and it can normalize in a spatial period and a temporal period meanwhile. This research result provides the basic theory and analysis methods for the research on moving periodic structure, and there have been not similar research results published up to now. Further, using Floquet mode function, the expressions of fields in each region are obtained; according to the boundary conditions, the scattering characteristics of two MCDP structures, whose conductivity is sub-cycle uniform periodic distribution and sine distribution, are solved separately. Finally, simulating and a number of numerical results are used to illustrate the theoretical analysis.The paper also proposes a speed-frequency transduction (SFT) based on the electromagnetic scattering from MCDP structure, and comparing with traditional Doppler technique, it has unique advantages in application.