ADS momentum differential port can't be defined

Hi, all,

I used ADS momentum to draw two simple square-shape antennas with one single metal layer. I planed to use one of them as transmitter and the other as the receiver. There are two ports in each of the antenna and hence four ports in total.

Then I tried to define two different ports, namely port 1&2 in the first antenna as a group of diff pair and port 3&4 in the second antenna as another group of diff pair. When I tried to define the differential ports using port editor, it returned me the following error:

Port P2 cannot be associated with port number 1.
If they are in the same reference plane, and you want to associate them:
Please set both ports to the correct Port Type before
setting ^Associate with port number^

And this happened as well to port 3&4.

Could anyone help resolve this problem? I have been stuck on this for quite a while...

I really appreciate your help!

grit_fire , I found the solution to this after much head breaking , here concentrate on the word "reference plane " , Ports having same reference plane means that they either have the same X co-ordinate or the same Y co-ordinate , You should see only one white line and not two which ADS draws passing through each port , and don't trust what it looks , zoom it as much as you can and there should be only one line and ports 1 co-ordinate should be exactly same .

Let me know if this is not clear.

Regards'
Gaurav
Indian Institute of Science

Thank you so much! Gaurav.

After making only one white line pass througth each port, the differential port can be defined.