The MoM-PO hybrid method for calculating the scattered field of multi-scale composite targets

Method of moments (MoM) and physical optics (PO) hybrid algorithm is the main method for calculating scattered field of electrically mid-scale and multi-scale target. When calculating the coupling effect between MoM region and PO region, we have to judge whether the PO elements is illuminated. Time complexity of shadowing algorithm based merely on CPU is O (N²) where N represents to the patch number of the target, which increases sharply with the increase of patch number. In this paper, we use GPU rendering and zbuffer to accelerate the process of lit judge. The time consuming of shadowing process has no relation with increasing patch number and has a better performance especially when the patch number reaches 10⁵ magnitude. We apply MoM-PO method to the scattered field calculation from the complex target combined with rough surface. Compared with the multilevel fast multipole algorithm (MLFMA) and PO method, this hybrid method achieves high precision. The hybrid algorithm has obvious advantage over single method algorithm.