This paper introduces a time-domain combined field integral equation for electromagnetic scattering by a perfect electric conductor. The new equation is obtained by leveraging the quasi-Helmholtz projectors, which separate both the unknown and the source fields into solenoidal and irrotational components. These two components are then appropriately rescaled to cure the solution from a loss of accuracy occurring when the time step is large. Yukawa-type integral operators of a purely imaginary wave number are also used as a Calderon preconditioner to eliminate the ill-conditioning of matrix systems. The stabilized time-domain electric and magnetic field integral equations are linearly combined in a Calderon-like fashion, then temporally discretized using a proper pair of trial functions, resulting in a marching-on-in-time linear system. The novel formulation is immune to spurious resonances, dense discretization breakdown, large-time step breakdown and dc instabilities stemming from non-trivial kernels. Numerical results for both simply-connected and multiply-connected scatterers corroborate the theoretical analysis.

翻译：本文提出了一种用于理想导体电磁散射的时域组合场积分方程。该新方程通过利用拟亥姆霍兹投影子推导得到，这些投影子将未知场和源场分别分解为无散分量和无旋分量。随后对这两个分量进行适当缩放，以消除时间步长较大时解的精度的损失。还采用纯虚波数的汤川型积分算子作为卡尔德隆预条件子，以消除矩阵系统的病态。稳定化的时域电场和磁场积分方程以类似卡尔德隆的方式线性组合，然后使用适当的试验函数对进行时间离散化，得到步进时间线性系统。该新公式对虚假谐振、密集离散化崩溃、大时间步长崩溃以及由非平凡核引起的直流不稳定性均具有免疫性。数值结果验证了理论分析的正确性，涉及单连通和多连通散射体两种情况。