Discussion Forum

Hi everybody, I need to simulate the 2D problem of plane wave scattering by a dielectric corner (see attached figure).
The model I have built up with Comsol uses the In Plane TE waves module (harmonic propagation). The simulation region is a box (air) in which there is another box (lossless dielectric corner) . This last is theoretically infinite and so must be terminated with a Perfectly Matched Layer. The plane wave direction is described by the arrow.
In my model, I have bounded the computational domain with PMLs . These are composed of boxes matched to free space and boxes matched to the lossless dielectric. The boundary settings I have employed are:
- scattering boundary conditions (plane wave) for the outer boundaries of the domain
- continuity for all the others.
The results I found running Comsol are shown in the attached figure and not acceptable since the level of reflections at the bottom of the corner is high (see the interference pattern and the field level in the PML).
I wonder if there are any mistakes in my model and my major doubts are about the use of the PMLs. For what concerns the PML matched to free space I have followed the tutorial Dielectric scattering (automatic choice for the parameters Sdx, Sdy). Then, I have set the PML matched to the dielectric in a similar way just changing the value of the dielectric constant. However, I don't know if an optimization of the PML parameters (thickness,etc) is required for this kind of problem.

Thanks in advance