In simulating some structures with varFDTD, I have several general questions which I hope can be addressed regarding simulation setup.
Is there a suggested minimum distance between the simulation boundary of the varFDTD region and the location of the varFDTDModeSource/varFDTDModeExpansionMonitor/varFDTDFrequencyMonitor?
How will violating the minimum distance (if there is one) affect the results of the simulation?
Similarly, if the goal of the simulation is to measure the S parameters of a structure (say a 2 port structure, so 1 input port and 1 output port, with propagation in the x direction):
- How should the varFDTDModeSource be positioned with respect to the varFDTDFrequencyMonitor for the “input”? (ie should they be separated in the x direction?)
- If the input and output waveguides have the same cross section, can/should a single mode expansion monitor be used, with both input and output frequency monitors added? Or should separate expansion monitors be used, one for input and one for output. In both cases, when should “align to frequency monitor center” be used?