Which one is more important? S11 or S22?

Assume that there is a 2 port network, and the port is fed at port 1, in this case is S11 more important or S22?

if the network is reciprocal they are both the same , but if not , u need to know , every one of them to know , how this network will behave from every port

khouly

The relative importance of s11 and s22 depends upon your application. A general answer is to make both as low as practical.

S11 AS WELL AS S21 ARE BOTH IMPORTANT AS S11 GIVES YOU INSERTION LOSS & S21 GIVES U POWER GAIN

If you think only to the level of importance, the answer is: S11 for Low Signal Amplifiers, and S22 for Power Amplifiers.

depends on the stage of the system you are designing. I wouldnt care too much about s11 if that is my first stage amplifier.

Added after 2 minutes:

yeah but the first stages are better if they are also low noise and low noise is achievable only by good s11. so you see the comprimise.

Added after 1 minutes:

microwave is never so easy to reduce it down to s11 and s22.

both of them are important because matching in lna is more important either in input or in output.but i think the s11 is more important than the s22. because matching in the input of lna is more critical than the output.

If you have a bandpass filter it is important to terminate it properly so S11 or S22 importance depends on application.

Filters need to be terminated against their terminal design impedance, not matched to (in terms of maximum power transfer).

I agree with khouly, it depends whether the device is reciprocal or not.