A Novel Method for Accurate and Rapid Evaluation of Large-Scale Array Scattering Under Measurement/Simulation Conditions

In this article, a novel method named mode filtering and subarray expansion (MF-SAE) for accurate and rapid evaluation of large-scale phased array scattering is proposed. Unlike traditional methods, this approach transforms the evaluation of large-scale array scattering into the total scattered field of a small subarray. The scattered field of the element in the array environment can be analytically separated from the total scattered field of the subarray based on spherical wave expansion (SWE) and mode filtering. The calculated element fields include coupling effects. Subsequently, the element field of the large array can be regarded as equivalent to the subarray element field under a similar coupling environment. This method solves the problem that the scattered field of the elements in an array cannot be directly obtained by measurement or simulation software. The MF-SAE method significantly reduces time consumption and memory requirements while maintaining high accuracy. The computational problem of a large-scale array is transformed into that of a $1\times 7$ or $7\times 7$ subarray. The amount of computation does not increase with the size of the large-scale array. The effectiveness of this method has been verified through the simulation and measurement of different array models. The radar cross section (RCS) error is below 1.5 dB in simulation and reaches 2.3 dB in measurement.