Huang Zhixiang

Perfect plane-wave source for a high-order symplectic finite-difference time-domain scheme

The method of splitting a plane-wave finite-difference time-domain (SP-FDTD) algorithm is presented for the initiation of plane-wave source in the total-field / scattered-field (TF/SF) formulation of high-order symplectic finite-difference time-domain (SFDTD) scheme for the first time. By splitting the fields on one-dimensional grid and using the nature of numerical plane-wave in finite-difference time-domain (FDTD), the identical dispersion relation can be obtained and proved between the one-dimensional and three-dimensional grids. An efficient plane-wave source is simulated on one-dimensional grid and a perfect match can be achieved for a plane-wave propagating at any angle forming an integer grid cell ratio. Numerical simulations show that the method is valid for SFDTD and the residual field in SF region is shrinked down to −300 dB.

Total field and scattered field technique for fourth-order symplectic finite difference time domain method

Using symplectic integrator propagator, a three-dimensional fourth-order symplectic finite difference time domain (SFDTD) method is studied, which is of the fourth order in both the time and space domains. The method is nondissipative and can save more memory compared with the traditional FDTD method. The total field and scattered field (TF-SF) technique is derived for the SFDTD method to provide the incident wave source conditions. The bistatic radar cross section (RCS) of a dielectric sphere is computed by using the SFDTD method for the first time. Numerical results suggest that the SFDTD algorithm acquires better stability and accuracy compared with the traditional FDTD method.

Perfect plane wave injection into 3D FDTD (2, 4) scheme

In the paper, the authors derive the method of splitting plane wave FDTD (SP-FDTD) method for initiation of plane wave sources in the total-field and scattered-field (TF/SF) formulation of 3D FDTD (2, 4) scheme. By splitting the fields on 1D auxiliary grids, the identical dispersion relation can be obtained between the 1D auxiliary grids and the 3D grids, which is also proved to be using the nature of plane wave. Using 1D auxiliary grids for introducing a plane wave, a perfect plane wave injection can be achieved at any angle forming an integer grid cell ratio. Numerical simulations also indicate the efficiency and validity of the method for FDTD (2, 4) scheme and the leakage error on the order of −300dB for double precision.

Hybrid Lifting Wavelet-Like Transform for Solution of Electromagnetic Integral Equation

A hybrid lifting wavelet-like transform scheme is successfully applied to the solution of electric field integral equation using Rao–Wilton–Glisson basis functions. To speed up the matrix transform process, the lifting scheme is adopted. Numerical examples of different three-dimensional perfectly electric conducting objects are considered. Compared with the method of moments, the proposed matrix transform scheme can save considerable CPU time and memory.

Solving multi-object radar cross section based on wide-angle parabolic equation method

Abstract Based on a Pade approximation, a wide-angle parabolic equation method is introduced for computing the multiobject radar cross section (RCS) for the first time. The method is a paraxial version of the scalar wave equation, which solves the field by marching them along the paraxial direction. Numerical results show that a single wide-angle parabolic equation run can compute multi-object RCS efficiently for angles up to 45°. The method provides a new and efficient numerical method for computation electromagnetics.

Study the nonlocal optical properties of typical two-dimensional nanostructures

Due to the existence of the quantum effect, the characteristics of nanostructure is difficult to explain entirely based on classical mechanics method. With the development of the FDTD method, its application in the field of optics is becoming increasingly widespread. In this paper, based on finite difference time domain (FDTD) method to study the nonlocal optical properties of two-dimensional structures was applied directly. The existence conditions of local and nonlocal optical characteristics under different nanometer radius, the impact of structural shapes with their extinction cross section properties were also obtained. The numerical results clearly show that with the decrease of the nanometer structure size and the shape of the structure, the non-locality becomes more pronounced. Our theory and results can provide a reference for the practical design of new nanoscale devices.

Simulation of nonlinear hybrid circuit by FDTD

Make full-wave analysis of micro-strip low pass filter and nonlinear hybrid circuit with FDTD (Finite-Difference Time-Domain) algorithm, obtain the distribution of the electromagnetic field of the circuits at different moments, and the simulation result of FDTD and commercial software are highly consistent. As FDTD is a full-wave simulation, the calculation results are more accurate than those traditional circuit simulations, and the field value and distribution of electromagnetic field responding to high-frequent signal can be attained directly, which has important significance for researching the problems about electromagnetic compatibility and so on.

Perfect plane wave injection for symplectic finite-difference time-domain scheme

In this paper, the method of splitting plane wave finite-difference time-domain (SP-FDTD) algorithm is presented for the initiation of plane wave sources in symplectic finite-difference time-domain (SFDTD) scheme. By splitting the fields on one-dimensional (1D) grid and using the nature of numerical plane wave in FDTD, an efficient plane wave sources is simulated on 1D grid, and a perfect match is achieved for a plane wave propagating at any angle forming an integer grid cell ratio. Numerical examples show the valid of the proposed method.

An efficient splitting the plane-wave FDTD method

The paper presents a new efficient method of introduction of plane wave source into finite difference time domain (FDTD) grids: the method of splitting the plane-wave FDTD (SP-FDTD). The new equations for the 1-D propagator are based on spitted-field Maxwells equations, and the propagator makes the 1-D and 2-D dispersion equations identical. The technique virtually eliminates numerical dispersion, filed location and polarization mismatches between propagator and main grid, for a plane wave propagating at an angle forming an integer grid cell ratio, which can represent almost any angle in theory. Through the leak test of the different incident angles of the Gauss pulse plane wave source in 2-D, it shows that, the technique can achieve a perfect total-field scattered-field separation, making leakage down to −340 dB levels.

A second order symplectic partitioned Runge-Kutta scheme for Maxwell's equations

We construct a new scheme for approximating the solution to infinite dimensional non-separable Hamiltonian systems of Maxwells equations using a second order symplectic partitioned Runge-Kutta (PRK) method for the first time. The scheme is obtained by discretizing the Maxwells equations in the time direction based on symplectic PRK method, and then evaluating the equation in the spatial direction with a suitable finite difference approximation. Also numerical examples are presented to verify the efficiency of the scheme.