Research Of Dispersive FDTD Method And Applications

Due to the universal existence of dispersive media in nature, and the importance of the electromagnetic wave propagation problem in dispersive medium in the field of radar target scattering, biomedical diagnosis, electromagnetic and optical element detection, in the paper, the finite difference time domain(FDTD) algorithm for dispersive media is studied deeply, and it is applied into the analysis of relevant electromagnetic problem in dispersive medium, the work mainly contains the following:1、Due to the time-domain relation of signal and system in digital signal processing, a general SARC-FDTD method is discussed for dispersive media, and the updating formula is derived for UPML absorption boundary condition of dispersive media based on SARC method, finally, the good absorbing effect of UPML absorbing boundary is verified by the radiation of electric dipole source, the correctness and the universality of the SARC-FDTD method are verified by the calculation of common dispersive medium plate’s reflection coefficients and medium sphere’s radar scattering section;2、The SARC method for dispersive medium is applied into the analysis of metals’ optical property. For wave band of visible light and infrared light, common dispersive medium models of metal is summed up, and unified expression of polarizability function is given, for the expression, the general improved SARC-FDTD method that is suitable for the analysis of metals’ optical property is derived, finally, the reflection coefficients of metal aluminum plate of different dispersive models are calculated using the method;3、SARC algorithm for dispersive medium is applied into FDTD analysis of layered dispersive medium. Starting from 2D Maxwell’s curl equations, a general SARC-FDTD correction method of dispersive medium which is introduced by oblique incidence plane wave is derived in the two modes of TE and TM, and the updating formula for UPML absorption boundary condition of layered dispersive media based on SARC-FDTD method is derived, and then combined with theory solution, the applicable range of the oblique incidence angle of general SARC-FDTD correction method is studied, finally, the SARC-FDTD correction method is used in the analysis of electromagnetic property of tumor tissues.