A Flexible Numerical Integration Strategy for Accurate Simulation of Cavity Scattering Problems

Accurately simulating electromagnetic scattering within cavities presents significant challenges due to the intricate wave behavior. Beyond the well-known convergence issues, this work focuses on the sensitivity of computational accuracy during numerical implementation. Our research identifies that the accuracy of the integral equation (IE) method is significantly influenced by the Gaussian integration rule. Specifically, achieving high accuracy requires high-order Gaussian integration rules, which in turn increase computational time. To address this issue, we propose a flexible numerical integration strategy (FNIS) that adaptively selects integration rules based on the distance between basis and test functions. Numerical examples validate our approach, demonstrating improved computational efficiency while maintaining high accuracy.