cst waveguide port

Dear all,

I have a question about defining waveguide port for coax cable in CST.

In the example of patch antenna in the CST manual, it needs to define the Zmin as electric wall, and then pick up the coax cable down face as waveguide port location.

However, if I want to know the backward radiation of the antenna, so it is not suitable the define Zmin as electric wall, so it is still possible to pick up the coax cable down face as waveguide port? It seems the simulation can not converge, so what can I do to solve this problem?

Thanks for your time, and I will appreciate all your reponse.

The example in CST MWS probably relates to a specific antenna structure where the antenna is backed by a metal wall anyway, so the choice of Zmin=Electric is a good way to reduce calculation time (instead of modelling a metal wall).

If you want to simulate an antenna without any preliminary assumptions, then use
the same settings in the example, but leave all the boundaries - Open (add space).

Regads,
P.

Hi winglj

Another better way to reduce calculation time is to assign first in the
Background Properties Lower Z=5 or10mm then in the Boundary Condition
Assign Zmin=open. And only after this pick the coax face and define the Port.

PL

I think your problem is in the portcalculation itself. have you seen the field at the coaxial cable port? in most of the cases I have problems concerning coaxial cables, the problem was in the port field calculation. If you want the port field to be correct, increase the diameter of the outer shell such that the port solver sees only metal and the dielectric, not the outer air.

set the boundary condition to be Open add space,you can get a full radidation patterns