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A Fast Numerical Algorithm for Calculating Electromagnetic Scattering from an Object above a Rough Surface

Abstract A fast numerical algorithm is proposed for calculating the difference field radar cross-section of an object above a rough surface. The electric-field integral equation of the difference of the induced current on the rough surface and the induced current on the object is derived, which is solved by an iterative solver. The characteristic basis functions are used to calculate the induced current on the rough surface, which is part of the right-hand side of the system. It is observed that the coupling matrices (nonself-block interactions of the rough surface and the interactions between the object and the rough surface) are rank deficient. The matrix decomposition algorithm is used and extended to compress the coupling matrices. Numerical examples show that the characteristic basis functions method combined with the matrix decomposition algorithm can greatly reduce the CPU time and memory cost. The accuracy and efficiency are discussed by numerical examples.