As can be seen from the above criterion, a high resolution mesh requires a smaller time step. Since you need to let the fields in the computational domain fully evolve over time, a smaller time step will require a larger number of time steps to achieve convergence. [[EM.Cube]] automatically chooses a time step that satisfies the CFL condition.
For more detailed information, see [[[Waveform, Bandwidth, Stability]]]].
===Perfectly Matched Layer Termination===