U just need to add LumpedRLC component in the plane of 3rd port to model its termination. or add a third port but do not activate it

To Ahmed Deel,

Thank you for your reply.....

But, How to deactivate the port?

Hi, 

Go to HFSS------>Fields------->Edit Sources

In edit sources window you can active or deactivate the ports you want.

To Subin,

I tried in that way also, but the results are same in both cases.........

In HFSS or any other software, each port will be excited individually and measure S parameters; so when you deactivate your port the software measures its receiving parameters only

To Ahmad deel,

If that is the case, then I should get similar results in case of three ports excited at a time and two ports excited (remaining port is terminated by 50ohm).

But, I am not getting them.....

Right now, I am using Lumped RLC for matched termination.... Is it correct?

Putting a 50 Ohm resistor at a port means the port is passive.

Hi Anvesh,

If you work in the 50 ohms system and you are designing a three port (or a multiport),   you need to connect the unused (s) port to 50 ohms load (s). The 50 ohm load is composed of 50 ohms resistor and a connection to the ground. The same procedure in the two port measurement using the network analyzer.  A 50 ohms load or 50 ohms integrated resistor with a RF short circuit (or via-hole) in the case of on wafer measurements.

Hope this will help.

Hammou