Hi All!
When I read about a particular discrete amplifier circuit, and they begin discussing the S11 and the S22 of the amplifier, the return loss is normally only around -13dB or less. Some are even less than
-9dB! What I don't quite understand is: Why can't designers
*significantly* improve the amplifier's return loss to far better levels, since the matching circuit (if designed correctly) will "force" the transistor to see the conjugate of its impedance; as well as also, I would think, force the outside world to see an almost *perfect* 50 ohm match. In other words, why can't the input/output return losses of real amplifiers be, let's say, better than -20 or -30dB (within a certain narrow frequency band), rather than the mediocre -13dB or less levels? And if this cannot be done for whatever reason, why not just add a simple L network at the already matched amplifier's ports to better the return loss to much greater levels?
Thanks,
-Bill xxxxxxxx
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