Accelerated Hybrid Method for Electromagnetic Scattering From Multiple Complex Targets Above a Rough Surface

Guilong Tian,Tong Wang,Chuangming Tong,Dongli Tang

doi:10.1109/access.2021.3074574

Guilong Tian, Tong Wang + Show 2 more

Open Access

https://doi.org/10.1109/access.2021.3074574

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Journal: IEEE Access	Publication Date: Jan 1, 2021
Citations: 30	License type: CC BY 4.0

Affiliation: Air Force Engineering University

Abstract

A hybrid scheme that combines the pre-corrected fast Fourier transform (p-FFT) and iterative Kirchhoff approximation (IKA) is developed to solve the electromagnetic scattering from multiple complex targets above a three-dimensional (3D) rough surface. Based on the domain distribution method (DDM), multiple targets are divided into an FFT region, and the rough surface is divided into an IKA region. Scattering on the FFT region and IKA region is calculated by p-FFT and IKA, respectively. In addition, iterative strategies are considered in both solving interaction between facets in the IKA region and interactions between FFT region and IKA region. However, interactions between FFT region and IKA region are the most time-consuming in the entire computational process. To overcome this computational bottleneck, the combined multilevel fast multipole algorithm (MLFMA), ray-propagation fast multipole algorithm (RPFMA) and fast far-field approximation (FAFFA) are incorporated into interactions between FFT region and IKA region. They accelerate the matrix vector multiplication by “interpolation –translation –anterpolation”, while their translators are different, which result in their different computation efficiencies and application conditions. To effectively combine these three algorithms, the IKA region is divided into MLFMA area, RPFMA area and FAFFA area according to the distance, where interactions between these areas and the targets are accelerated by MLFMA, RPFMA and FAFFA, and the surface outside these areas is discarded. Compared with MLFMA, the accuracy and efficiency of this hybrid method are verified.

Highlights

The composite scattering characteristics from multiple targets and rough surface are widely used in both military and civilian applications [1], [2]
The rough surface scattering is calculated by the first-order Kirchhoff approximation, the target impedance matrix is accelerated by AIM, and the coupling between the target and the rough surface is accelerated by multilevel fast multipole algorithm (MLFMA)-fast far-field approximation (FAFFA)
Target scattering is solved by pre-corrected fast Fourier transform (p-FFT), rough surface scattering is computed by iterative Kirchhoff approximation (IKA), and the interactions between targets and rough surface are iteratively solved

Summary

INTRODUCTION

The composite scattering characteristics from multiple targets and rough surface are widely used in both military and civilian applications [1], [2]. By applying the numerical method to solve for the scattering from targets due to the complex structure and the high-frequency method to compute the large-size rough surface, the hybrid numerical-analytical method promises the accuracy and efficiency for computation. During the entire process to compute composite scattering, solving interactions between multiple targets and rough surface is the most difficult bottleneck. MLFMA and RPFMA with FAFFA are first combined to accelerate the matrix vector multiplication between targets and rough surface. The rough surface scattering is calculated by the first-order Kirchhoff approximation, the target impedance matrix is accelerated by AIM, and the coupling between the target and the rough surface is accelerated by MLFMA-FAFFA. For the coupling and interaction between the target and the environment, this article uses MLFMA-RPFMA-FAFFA to accelerate matrix vector multiplication.

The induced currents on facet i are

Findings

CONCLUSION