What does the phase of S11 mean?

Hi! I have a basic S-parameter's problem need help.I know the mag of S11 is (|ind wave|)/(|ref wave|) at port1 and S22 matched at Z0. but what is the phase of S11 means?

-CQCQ

it is the phase angle of return loss of one-port or two-port network referenced to input of network

good luck,

This is a difference between input signal and reflecting signal

Go tie a 10 foot length of rope to the wall. Whip the open end of the rope to sent a pulse down the rope toward the wall. Notice what happens to the pulse after it reflects? It changes orientation by 180 degrees. So, for the rope, a short circuit termination has a 180 degree S11 phase angle.

You can get any phase angle you want by loading the terminating end properly.

S11 mag is more often cared about than its phs in practice , i am afraid. However, phs info can be used to know properties of the load, e.g. to tell O.C. or S.C. load.

Have a deep look at a Smith Chart!
It will help you a lot.
Max

S11 has two parts. real and imaginary, real part represents resistive part of mismatch and imag represents reactive, this reactive can be capacitive or inductive depends on sign of imag part, now each complex number can be written in form of mag and phase.
if you draw S11 on smitch chart you will get the correct understanding,