The Scattering Properties Research Of Electromagnetic Wave In Isotropic And Anisotropic Left-handed Medium

Left-handed material whose permittivity and permeability are all negative was introduced by soviet scientist V. G. Veselago in 1968, and this metamaterial was man-maded by American scientist D. R. Smith who is in University of California at San Diego in 2000 in terms of the theoretical results of J. B. Pendry in London imperial college. The theoretical and experimental results show that left-handed material can be fabricated and analyzed. Because of its potential applications in the radar technology, antenna and near field optics et al, more and more scientists are interested in it and devoting the research on its physical properties, experimental fabrication and numerical simulation of this media.In this disseration, the physical properties and potential applications of left-handed material are explored, from theoretical analysis to numerical simulation and then software simulation. The main work are divided into four parts:First, unsplit dispersive finite difference time domain which is applicable to left-handed material is proposed; second, the results of radar cross section of left-handed material sphere and the metal sphere coated with left-handed material is simulated by matlab; third, the near field property of the metal sphere coated with left-handed material is simulated by HFSS; and at last, the near field property of the anisotropy left-handed material sphere is simulated by HFSS. The tasks of this disseration are as following:1. A novel unsplit FDTD method which could unite the inside field and absorption layer iterative process is proposed in the second chapter. This method achieve the unite iteration just by changing the parameter of iteration. Combining the unsplit FDTD method with shifted operator method, the matlab program for this disseration can analyse isotropic dispersive left-handed material. It can make full use of the temporary variables and make the program concise and efficient.2. A matlab program of three dimensional unsplit dispersive FDTD is programmed based on Drude dispersion mode in the third chapter. We calculate the radar cross section of left-handed material sphere and metal sphere coated with homogeneous left-handed material. At last, we discuss the difference of radar cross section when the layer equivalent refraction index is changed.3. The difference of electric field intensity distribution which the sphere suffers from is discussed in the forth chapter when the coated material's parameters, thickness, or the distance between the metal sphere and radiation point source are changed. It intuitively demonstrates the advantages of left-handed materials in target radar stealth.4. The property of medium with different symbols of permittivity and permeability tensor is discussed in the fifth chapter. We simulate the near field properties of the anisotropy left-handed material when the Gaussian pulse beam illuminate the sphere. It intuitively demonstrates the excellent microwave absorbing properties of anisotropy metamateral sphere.