Systematic configuration of coarsely discretized 3D EM solvers for reliable and fast simulation of high-frequency planar structures

Accurate simulation of microstrip and other planar structures at very high frequencies usually requires employing full-wave electromagnetic (EM) solvers. For planar circuits, 2.5D EM solvers are especially suited and easy to configure. However, in some cases, planar circuits are required to be simulated in 3D solvers. On the other hand, low-resolution discretization in 3D solvers is necessary when coarse models are employed for direct EM optimization, for instance, in space mapping methodologies, or in surrogate-based modeling techniques. In this work, we propose a systematic methodology to find a suitable 3D EM solver configuration when low-resolution meshing is needed for reliable and fast simulation of planar structures. We illustrate how improper configuration of the 3D EM solver might lead to significant alteration of the inherent structure´s EM response, as well as to numerical noise that affects the parameterized usage of these models, such as in direct EM optimization. Our technique is illustrated by a couple of classical microstrip filters simulated with a commercially available 3D full-wave EM solver.