I'm looking for information on the performance of Mini-Circuits T16-1-KK81+ transformer. The transformer is well-characterized, Mini-Circuits provided both insertion/return loss charts and raw S-parameter measurements for download.
I'm having difficulties on reproducing the official return loss chart using the raw S-parameters.
It's a 4-port VNA measurement with 16 S-parameters, the
s4p file says,
!Model: T16-1 !Run/Lot/Date Code: MW42300//0640 !DATA FOR: UNIT#1 !Fixture/SN/Due: 90-2-20-233/72223/07-24-2009 !Connection: PORT-1 - pin<4>; PORT-2 - pin<6>; PORT-3- pin<3>; PORT-4 - pin<1>; !PORT EXTENSION DONE ON TEST FIXTURE WITH LOSS ON AND MISMATCH ON
The primary dot is Pin 4, or port 1, so the return loss should be a plot of S11, but the plot looks like this,
In no way it resembles the official return loss curve,
I thought the script I used to plot the chart was broken, but I don't see obvious issues in my code. I suppose the difference is due to the termination. I guess the VNA measurements were done with four 50Ω ports, but the return loss chart in the datasheet assumes a matched 800Ω load, is it correct?
How should I proceed to reproduce the return loss chart?