VOLMAX: a solid-model-based, transient volumetric Maxwell solver using hybrid grids

This paper provides an overview of the finite-volume algorithm, the dissipative time-integration scheme, boundary condition implementation, grid generation, and a time-step definition suitable for sub-time cycling. To examine the accuracy of VOLMAX operating in either a purely unstructured or a hybrid-grid mode, the resonances of a rectangular cavity, the input admittance of a "thick" wire antenna, and three simple microstrip applications (microstrip line, patch antenna and low pass filter) with well-known FDTD solutions are examined. The latter three examples demonstrate the accuracy that can be obtained by launching microstrip-guided waves on cubical hexahedral (FDTD) grids and through a dense, unstructured linear tetrahedral region.