A Nonoverlapping Hybrid FDTD-PITD Method Using Upwind Conditions for Multiscale Problems

The transient analysis of multiscale problems, involving electrically small fine details and relatively uniform areas, has a wide range of applications in practical engineering, posing significant challenges to any single algorithm in computational electromagnetics (EMs). Here, a novel hybrid approach combining the finite-difference time domain (FDTD) method and the precise-integration time domain (PITD) method is proposed to handle such problems. FDTD is applied in uniform areas, whereas PITD is used in fine detail areas. Meanwhile, the conformal modeling of dielectric materials and metallic objects is introduced into PITD to handle sophisticated and irregular fine structures. For the hybrid method, the field values in the FDTD and PITD domains are calculated separately and independently. The information transmissions between two solution domains are achieved by correcting the interface field components via the upwind conditions. Several numerical experiments are presented to demonstrate the effectiveness and advantages of the hybrid method, that is, it requires less execution time than FDTD and less memory cost than PITD.