A Dual-ACA-MoM Algorithm for EM Scattering From Multiple Identical Rigid Targets

To solve the electromagnetic (EM) scattering from multiple identical rigid targets with traditional adaptive cross approximation method of moments (ACA-MoM), the multiple targets are treated as a single entity. ACA is introduced directly to the octree’s finest layer neglecting the characteristics of the targets. This leads to redundant storage of submatrices, low simulation efficiency, and large memory requirements. To address these limitations, a new algorithm named Dual-ACA-MoM is proposed and validated in this article. The new approach leverages the translation rotation invariance of the Green’s function, requiring only the calculation and storage of a single self-interaction impedance submatrix. This significantly reduces simulating time and memory requirements. Moreover, ACA is applied to two levels in Dual-ACA-MoM: the octree’s finest layer and the target layers. This dual application further reduces matrix filling, CPU time, and memory requirements. The numerical results demonstrate that the proposed algorithm effectively reduces memory requirements and simulation time while maintaining computational accuracy compared to both MoM and ACA-MoM.