Plane wave with Master Slave in HFSS

Hey ,

I created HFSS simulation that contains a structure, surrounded by air box.
Mastr\Slave boundary conditions were forced on each face of the box (3 masters and 3 slaves).

The structure was illuminated by a plane wave.

I received the following warning: Computations for incident wave excitation (except near field) require either radiation boundary or a PML.

My goal is to compute the E field at the origin.
What is the meaning of radiation boundary or PML in this infinite periodic structure?

Can I use plane wave excitation in this situation?(All of the air box faces were forced master or slave boundary condition).

thanks !

Probably, you only want Master/Save boundaries on two of the three axes, not all three. If the plane wave is propagating along a given axis, remove the Master/Slave pair on those faces and replace with radiation boundaries (or PMLs).

I've thought about that, but i wonder what does I simulate if master/slave applied on three axes?

Is this type of warning is critical If I look for the E field at the origin?

I would think it is, yes. Look at the fields in either case and see -- perhaps they might be the same?