I want to simulate S-parameter for differential circuit. How should I connect termination to each port ?
1: termination to each port or termination between P and N (of single port)
I have attached example circuit, which type is correct way to do differential simulation ?
You can use a connection scheme like "Type 2" in your image, or use transformers to convert a differential response to a single ended response. If you want a true mixed mode response, please see the Data Display template under Schematic window > DesignGuide > Signal Integrity Applications.