electric mode field for listener ports in wave optics module

Hi ,

In wave optics module(COMSOL 5.2a.) I want to define a 6-port domain . (lambda = 500[nm])

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. so, I define "user defined" ports. I set x component of incident electric field to 1 and also propagation constant to abs(kbz) . ( = ewfd.k0 * cos(theta) )

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 !