The distance between the PML boundary condition and the waveguide
I have a question.
I want to know how much the distance between the PML boundary conditions and the waveguide?
I wanted to know the optimal distance for simulation. for example FDTD, VarFDTD and FDE.
If the distance is large, the volume of the simulation area increases. Therefore the simulation time increases. Otherwise, if the distance between the boundary conditions and the waveguide is small, there is a possibility of error in the results.
Please guide me.