Wu Xianliang

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.

GPU-based accelerated FDTD simulations for double negative (DNG) materials applications

Recently, double-negative meta-materials are widely studied in scientific research. The double-negative (DNG) mediums are characterized by simultaneous negative permittivity and permeability. In order to make the FDTD method analyze the electromagnetic scattering and propagation for doublenegative (DNG) medium, z-transform is applied to the FDTD method in the double-negative (DNG) medium. For the simulations, extremely large computer memory space and a long computational time is required. A parallel algorithm for the FDTD method on the state of the art graphics hardware is presented. The parallel computing techniques can be used to reduce the computation time significantly and have been widely applied in various complex FDTD applications. In this paper, we simulate the interaction between electromagnetic wave and DNG medium, and describe an impact of new GPU features on development process of an efficient Finite Difference Time Domain (FDTD) implementation.

New algorithm of target classification in polarimetric SAR

The different approaches used for target decomposition (TD) theory in radar polarimetry are reviewed and three main types of theorems are introduced: those based on Mueller matrix, those using an eigenvector analysis of the coherency matrix, and those employing coherent decomposition of the scattering matrix. Support vector machine (SVM), as a novel approach in pattern recognition, has demonstrated success in many fields. A new algorithm of target classification, by combining target decomposition and the support vector machine, is proposed. To conduct the experiment, the polarimetric synthetic aperture radar (SAR) data are used. Experimental results show that it is feasible and efficient to target classification by applying target decomposition to extract scattering mechanisms, and the effects of kernel function and its parameters on the classification efficiency are significant.

Modeling for MIMO wireless channels in mine tunnels

The electromagnetic waves propagation situation is very complex in mine tunnels, so it is important to establish an efficient MIMO channel model for applying wireless communication technology to coal mine underground. A stochastic MIMO channel model is proposed firstly based on wireless propagation environment in mine tunnels, and then two spatial correlative channel models are established through correcting channel matrices based on abundant scatter environment. In this paper, the singular values and the channel capacity obtained with a Rayleigh channel model are compared, and system performance of different channel models are simulated. The simulation results indicate that established channel models are feasible by comparing with measurements results to mine tunnels.

UPML-FDTD parallel computing on GPU

Finite-Difference Time-Domain method (FDTD) which is known with its simple and flexible is widely used for the calculating of electromagnetic fields. However, it costs a lot of time in simulating the electrical-large object. To solve the problem, parallel method for UPML-FDTD algorithm was put forward using GPU based-on Compute Unified Device Architecture (CUDA) in this paper. The algorithm is further optimized by using texture memory. Comparing with the calculation with traditional CPU, The result of simulation shows that this algorithm has enough precision and the remarkable increased efficiency was acquired in different sizes of Yee cells.

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.

Scattering characteristics of dielectric periodic structures in the case of oblique incidence

The scattering characteristics of dielectric periodic structures in the general case of oblique incidence are investigated using a method that combines multimode network theory with a rigorous mode matching method. Some interesting wave phenomena are observed. It is demonstrated that the method is suitable for rigorously solving the electromagnetic scattering problems of the dielectric periodic structures and therefore lays a sound foundation for further research on accurately analyzing the wave phenomena and effectively designing the related periodic structures in MMW and optical integrated circuits.