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Voltage gain E21, Scattering transmission S21 and power gain

Question asked by JERRY_MARKETOS on Aug 9, 2004
From time to time, a user may compare the measurements of
E21 and S21, with the expectation that they will be similar in signature
and perhaps shifted only by some constant amount.  In fact, the
derivation of E21 and S21 and power gain are different, so the resulting
graph traces from these measurements can be significantly different-
this may not be intuitive at first.

Attached is an example file showing the measurements E21 and S21
and also calculated power gain for two simple passive circuits.  The
two passive circuits are identical, except that the first circuit uses
ports of equal terminations and the second circuit uses ports with
arbitrarily varying port impedances.

The example illustrates that E21, S21 and power gain are different.