Need expert help on impedance matching with identical transformers in series/parallel

Thread Starter


Joined Jun 14, 2009
Hello everyone. I'm not an expert here, but would really appreciate some help from this community. I'm trying to use RF transformers to inject sinusoidal noise onto load having a much smaller resistance than the source used to create the sinewave. To accomplish this, I'm cascading two identical transformers (Mini-circuits product number TTMO-25-1+) to get me in the right ball-park for impedance matching.

As the figure shows, my calculation estimates the power consumed by a transformer is 0.5W max, which is more than the 0.25W RF Power rating (although the datasheet rating is measured with test instrument at 50 Ohms source impedance, so I wonder if I can even compare my number to this value, anyone care to comment?). Note that the figure shows the turns ratio as 1:n, but I need 5:1 so I've set n=0.2 (don't let that confuse you). Also, I'm only using identical transformers, so no need to comment on what happens if they're different.

For figure 2, have I connected the additional two transformers correctly? I've tried to search on the internet, but couldn't find anything. So this is my best guess. It seems to make sense, but I'm looking for advice from someone much more knowledgeable. Is this sort of thing done (it's not my field).

Any help would be very very much appreciated. Thanks in advance -mmg