Hi,

I have a problem and propably the answer is simple. Suppose we have some lumped element circuit composing of inductor and capacitor S-paramater files (from manufacturer). How can I simulated the losses caused by the circuit? The reflection losses should not be included. If I have understood correctly, e.g. S21 includes the losses caused by the mismatch at the lumped element circuit input! And then again (if we have e.g. 50 ohm ports at the both ends) at the circuit output, there are again reflection losses, which causes multiple reflections in the circuit...Is it possible to calculate the losses from the simulated S-parameters of the lumped element circuit?? If there is some way, please let me know.

Thank you in advance:)

I have a problem and propably the answer is simple. Suppose we have some lumped element circuit composing of inductor and capacitor S-paramater files (from manufacturer). How can I simulated the losses caused by the circuit? The reflection losses should not be included. If I have understood correctly, e.g. S21 includes the losses caused by the mismatch at the lumped element circuit input! And then again (if we have e.g. 50 ohm ports at the both ends) at the circuit output, there are again reflection losses, which causes multiple reflections in the circuit...Is it possible to calculate the losses from the simulated S-parameters of the lumped element circuit?? If there is some way, please let me know.

Thank you in advance:)

In amplifier theory, this measurement is called "Maximum Available Gain".

Ref: Guillermo Gonzalez, “Microwave Transistor Amplifiers,” John Wiley & Sons, Inc., 1998.

You can use this measurement even on lossy circuits. ADS has made it simple for you to compute this. There is a built-in function called max_gain() which you can use to compute this. Assume the following circuit:

The cap and inductor on the input and output of this circuit adds a mismatch. If we match the circuit (at each frequency) then we should be able to get 1 DB loss.

If you simulate the S-parameters of the circuit you can then compute the "Max Available Gain" like this:

MinLoss = max_gain(S)

This will give you -1 DB for all frequencies, as expected.