TD-AIM-MOD method for simulating large-scale electromagnetic transients

This paper reports on a new hybrid TD-AIM-MOD scheme for analyzing transient scattering from the perfect electrically conducting structures. The scheme reduces the computational complexity of a classically formulated MOD solver from N_o²N_s² to N_olog²N_oN_s^1.5log²N_s - here N_o is the maximum order of the Laguerre polynomials used to expand the temporal current signature. Just as in MOT-TD-AIM solvers, the scatterer is embedded in a 3D regular grid and sources are projected onto this grid via moment matching. Next, fields are propagated on this grid by using a 3D spatial FFT and a blocked 1D “temporal” (order) FFT. Finally, fields at observers are obtained by interpolating their values from the regular spatial grid, followed by a near field correction operation. The accuracy and stability characteristics of the TD-AIM-MOD method are demonstrated via its application to large-scale scattering problems.