Port problem in pifa using cst software

HELLO everyone, how to solve this problem. I have run the transient solver, but cannot solve because there are two problems mention in the message window;
1. Port 1 is inhomogeneously filled within the first 3 mesh cell. Cannot start solver.
2. Error in calculating solver matrix
How to manage this problem? Urgent. Have to solve this week. TQ

Hi,
I suppose that your port is a waveguide port... and then the CST meshing need to have 3 meshcells free (no PEC!) to calculate mode, impedance...
that means that you have metal or other PEC in this area of the port.
Then check your port excitation, background properties and boundary conditions !
Other solution, if that is not coaxial port, you can use the discret port...
What is your model exactly ?
BR
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Hi,
I suppose that your port is a waveguide port... and then the CST meshing need to have 3 meshcells free (no PEC!) to calculate mode, impedance...
that means that you have metal or other PEC in this area of the port.
Then check your port excitation, background properties and boundary conditions !
Other solution, if that is not coaxial port, you can use the discret port...
What is your model exactly ?
BR

thanks a lot.. my model is PIFA-shorting plate. Now I can run the simulation but cannot get the operating frequency. The PIFA need 900 MHz and 1800 MHz. The return loss seems like straight line in decreasing form

Thank you Zebroo for your valuable info.
As I know discrete port is like a Voltage or Current source in opposite of Waveguide port which feeds using wave. Am I right?
If yes, could we put discrete port in Antenna design since wave is feeder?
Also I need to know about designing a pin in CST for PIFA. What exactly is the pin? is it like the internal part of Coaxial line or its thinner? I mean if I want to design a pin in CST should I consider it as a discrete port or as a Cylindrical waveguide port( same as Coaxial line).
Appreciated.