EM3DS (ElectroMagnetic 3D Simulator) is an equation based electromagnetic wave simulator. It uses a technique called Generalized Transverse Resonance Diffraction (GTRD) , developed by MEM (Microwave and ElectroMagnetics) Research. This simulator accounts for thickness, conductivity, etc. of real conductors or dielectrics.
The free version is an educational tool with less functionality. For complete features, you have to buy the full version. firstname.lastname@example.org