Port propagation constant in Comsol

Dear Friend,

Hi ,

I want to define a 6-port domain in COMSOL 5.2a. The domain contains 25 identical Rods.

I want to excite port#1 and read the powers arrive to another ports.

so , I define ports on wall of the Block domain. I also create exterior layer outside the domain and manually force the ewfd.Ex& ewfd.Ey& ewd.Ez to zero on this layer to absorb the received power on ports. I define "user defined" ports. I set x component of incident electric field of Port#1 to 1[v/m] and also the propagation constant to abs(kbz) . ( = ewfd.k0 * cos(theta) )

I attach the structure.

My question is :

1. what is the meaning of "propagation constant" for listener ports (port#2,3,4,5,6) and in this case what should I set to ?

2. what is the meaning of "electric mode field" for listener ports(port#2,3,4,5,6) and in this case what should I set to ?

3. Does any body have the same experience about this issue?

Thanks !