WaveSim (for time-domain electromagnetism) is one of my favorite programs because it generates such interesting physics. You can spend hours with the program rebuilding your friendship with the Maxwell equations. We don’t have as many orders for WaveSim as our static-field programs, so intervals may accumulate between tuneups. Therefore, I was happy when a consulting project gave me an opportunity to review the program.
I had two epiphanies as a I got reacquainted with WaveSim: 1) it’s really irritating to set up runs and 2) almost all the irritation follows from defining perfectly-absorbing boundaries. The instruction manual does list the formulas for calculating the real and imaginary parts of the permittivity and permeability, but there were three reasons why this fell short:
- I was tired of looking up the equations.
- I got tired of repeating the calculations (despite getting a free calculator when HP was late shipping my computer order).
- I always worried that I was making a mistake and the solution would be wrong.
After 15 years it dawned on me that this would be the perfect activity for the computer to handle.
I made simple changes to the WaveSim instruction set that cut the work of run preparation in half. The mysterious CondMode has been eliminated. It is no longer necessary to set the real and imaginary parts of material properties explicitly for absorbing layers. Instead, everything is taken care of by the command
ABSLAYER(RegNo) Delta [EpsiR MuR]
This is the same command used in Aether. The integer parameter RegNo is the number of region that has uniform thickness, usually a coating on the outside of the solution volume to define an anechoic chamber. The real number Delta is the layer thickness in the current units. The optional parameters EpsiR and MuR are required if the layer is adjacent to a non-vacuum material. WaveSim sets the proper values of complex permittivity or permeability depending on whether the 2D solution is of type E or H. In a frequency scan or resonance search, the program automatically adjusts the material parameters to follow the changing value of ?.