CST - How can I change the frequency setting for port modes in CST?

Hi,

Regarding the CST documentation, "By default this is the center of the frequency range given in the Frequency Range Settings". I need to know how 

  1. To change the port mode frequency without changing the desired frequency range.
  2. To obtain the Port mode information (such as Wave Impedance, beta or ...) for different frequencies with Post-Processing.

I appreciate your response in advance.

CST Studio Suite