difference between matched and terminated port

[kae_jolie]

What is the difference between matched and terminated port. I understand matching a port to 50 ohms would mean to match it to a 50-ohm transmission line (like coax) for max transmission, however what is terminating a port indicate? I think it means shorting it so it has no effect. I just need confirmation.

Also, in a real lab setting, how would you match a port and terminate a port?

I know this is a basic question, but would appreciate your input.

 

[barry]

They are interchangeable terms, inasmuch as you would TERMINATE a 50 ohm line with a 50 ohm load. (You could have a terminated port, although it could be terminated with the wrong impedance==> NOT matched)

 

[kae_jolie]

Thank you for your reply. I am going to be more specific. I am using HFSS to simulate a 3-element patch antenna array. I am trying to calculate S11, S12, S13, etc...As you could see in first 2 pics, each waveport is re-normalized to 50 ohms. In 3rd pic, in post-processing, the 3rd element is terminated with 50 ohms to find S12. HFSS makes distinct difference between the re-normalized (or matched) port and the terminated port. If I don't re-normalize the ports to 50 ohms, and just terminate elements with 50 ohms, the S-matrix results will be different. That's why I am saying they are two different things.

 

[barry]

Well, you've lost me; this is a little out of my field of expertise.

 

[ashiir]

I've never used HFSS so I don't know what does the re-normalized means.
However, from my point of view, there are some differences between matching and terminating port.
Matching mainly focuses on the port you are using, to make sure that you can get the maximum power transfer.
But terminating focuses on the unused port to cut that port off from the system you are testing.
In practical, the terminator are designed to absorb the incident power with little reflection so that it can not affect the measuring parameters.
Also, termination can make sure that the unused port will not resonate and not reflect the signal to damage a source and/or other devices.