Differential feeding in CST

Hello,
I want to know how we can feed two waveguide ports of structure simulated in CST by 180 degree out of phase signals?
Anyone can help me with that ?

In the launch window for the transient solver, you can set an option for 'Simultaneous excitation' instead of 'All ports (all modes)'. Through this, you can specify the powers and phases to be used for each port.
Another option is to solve for each port excited separately, and then use the 'Combine 3D results' post-processing template.

Thank you so much for your reply.
In the launch window for the transient solver, option for 'Simultaneous excitation' instead of 'All ports (all modes)'. we can specify the powers and phases to be used for each port at just one frequency and I want it on broadband of frequency. and to use 'Combine 3D results', is it necessarily to excited each port separately at each frequency as well ?

Set your frequency range to whichever band width you want. The transient solver will automatically calculate S-parameters for this entire range.
If you need field information, then you will have to insert field monitors at each of the frequency points.
Finally, you need to use the 'All ports' option in the transient solver. This will excite each port one after the other with the pulse automatically.