It is possible to get the s21 parameter by measuring the output of the USRP 2901, then measuring the power output after the PA. However, the USRP is not a measurement device, and will not give accurate information. As far as getting s11 measurements, the USRP lacks the circuitry to perform a power measurement as well as generate the signal at the same time. It wasn't built to take VNA measurements, so it will be difficult to get those measurements out of it.
Basically i am trying to find s11 parameter by transmitting signal from one usrp and receiving that signal from other usrp.There is a DUT (dielectric meduim) between these two usrp.So I am trying to figure out return losses(s11) for different frequencies.We do have VNA for confirmation that either our result is correct or not.But our project is to do it on usrp.
Kindly tell me if you have better approach to achieve it.
That sounds like you are doing an s21 measurement. You are measuring the power at port 2 from port 1. s11 would be measuring the power from the reflection of port 1 on port 1.
I guess you could split the signal before it goes into port 1 of the DUT and send it to the USRP receive. But you would be affecting your measurement with the second USRP.
Why are you trying to use the USRP to do this? It lacks the circuitry required to do an s11 measurement.
