Fast Calculation of Scattering in Planar Uniaxial Anisotropic Multilayers

Huiling Hu,Hongxia Ye,Ya-Qiu Jin

doi:10.1109/access.2019.2960079

Abstract

In this paper, the generalized recursive formulations of the finite difference time domain (FDTD) for updating the electric and magnetic fields in the multi-layer anisotropic media are derived with a uniaxial perfectly matched layer. The stability condition of the proposed method is clearly analyzed and verified. Then this method is used to calculate the three-dimensional complex scattering fields in planar multilayered anisotropic microstructures with optical axis perpendicular to the layered interface and the scattering fields of arbitrary shape scatters in the anisotropic layered structures. The electric field induced by the sine dipole source is calculated in the spatial domain and the corresponding spectral domain results are achieved through Fourier transform. The scattering field of composite materials with submillimeter thicknesses used in the industrial engineering is calculated using a terahertz wave with operation frequency of 0.3 THz. Robustness of the derived formulations for the complex uniaxial anisotropic media is verified by comparing with the COMSOL software, which is based on FEM analysis. The comparison of memory and CPU time shows the efficiency of the proposed FDTD method. Finally, the scattering fields of different scatters buried in multilayer anisotropic media are studied. So it is expected to become an effective simulation tool for dealing with complex electromagnetic environment in the future, such as abnormal detection of aircraft coating materials and detection of hidden target and so on.

Highlights

The attraction of the subject of wave interaction in planar multilayered media stems from its relevance to many practical applications, ranging from geophysical exploration [1]–[3] to electromagnetic performance prediction of microwave antennas [4]–[5], aerospace industry applications [6]–[8], and microwave/millimeter wave integrated circuit (MMIC) wave guides [9]–[10]
We extend the finite difference time domain (FDTD) method to analyze 3D electromagnetic propagation of terahertz waves in anisotropic multilayered medium structures, and the electromagnetic scattering of embedded bodies
The results show that the error between our FDTD method and the COMSOL software is less than 0.2 dB, which shows that the results are in good agreement and proves the validity of the method

Summary

INTRODUCTION

The attraction of the subject of wave interaction in planar multilayered media stems from its relevance to many practical applications, ranging from geophysical exploration [1]–[3] to electromagnetic performance prediction of microwave antennas [4]–[5], aerospace industry applications [6]–[8], and microwave/millimeter wave integrated circuit (MMIC) wave guides [9]–[10]. Yu Zhong et al further proposed Padua point integration method to deal with the Sommerfeld integrals related to the dyadic Green’s function for uniaxially anisotropic multilayers and studied the scattering problem of volume inhomogeneity in uniaxial planar layered media [13]. The volume differential equation method, usually implemented via the finite difference time domain (FDTD), is a popular approach for many scattering problems, such as electromagnetic wave propagation in inhomogeneous anisotropic media. Since the differential equation solving process is simpler and can be used to analyze continuous electromagnetic problems, the FDTD method has been widely used for electromagnetic scattering of inhomogeneous bodies embedded within multi-layer media. We extend the FDTD method to analyze 3D electromagnetic propagation of terahertz waves in anisotropic multilayered medium structures, and the electromagnetic scattering of embedded bodies. 4) FDTD simulations involving 3D-volumetric scatter with comparisons to finite element method (FEM) computations confirm the effectiveness of the approach and provide reliable benchmarks for further studies

MODEL AND METHODS

CONCLUSION