In simulations with multiple modes requested, the first several modes in a geometry may be far apart in frequency space. As a result, it may sometimes be difficult for the solver to accurately extract the high-frequency modes in the same simulation as the low-frequency modes. This will be apparent as convergence will require more AMR steps, and the mode frequencies may repeatedly change significantly between AMR steps. In this situation, the best results will be obtained if you run several simulations instead, where each new simulation contains a subset of the requested modes and the shift-frequency is raised appropriately.
In simulations with only lossless boundary conditions and materials, the electric field will be purely real and the magnetic field will be purely imaginary. Because only the real part of the field is shown by default in the field annotation, the magnetic field will initially appear to be zero. The imaginary component of the field may be viewed by changing the Display/Complex Modifier to Imaginary, as described in “Annotations”.
If the Mode Orientation path falls outside the simulation domain or in a part of the simulation domain where the electric field is zero, the AMR sequence will take longer to converge and may be more erratic. Whenever possible, define this path in a part of the domain where the electric field is has significant magnitude.