Study On Scattering Characteristics Of Gaussian Beam By An Arbitrarily Shaped Chiral Object

In this thesis, an analytical solution to the scattering by an arbitrarily shaped chiral object and an arbitrarily shaped object with a chiral inclusion, for arbitrary incidence of an on-axis Gaussian beam, is given. The main works are as follows:Firstly, an elaborate introduction of the electromagnetic fields in a chiral medium is presented, and an appropriate expansion of the EM fields in a chiral medium in terms of spherical vector wave functions (SVWFs) is given.Then, based on a combination of the extended boundary condition method (EBCM) and generalized Lorenz-Mie theory (GLMT), a semi-analytical solution to the scattering of an on-axis Gaussian beam by an arbitrarily shaped chiral object is given, by expanding the incident Gaussian beam, scattered fields as well as internal fields in terms of appropriate SVWFs. The unknown expansion coefficients are determined by using Schelkunoff s equivalence theorem and continuous boundary conditions. Numerical results of the normalized differential scattering cross section are presented, and the scattering characteristics are discussed concisely.Finally, by using the field expansions in terms of the SVWFs and the EBCM scheme, an approach to compute the scattering of an on-axis Gaussian beam by an arbitrarily shaped object with a chiral inclusion is presented. A greater impact of the chiral inclusion on the scattering characteristics, especially on the polarization properties of the scattered fields, is discussed concisely.