Preamplifier design : Input and Load reflection coefficient

Are you simulating the design or are you building it. In case of the later you need to measure the stuff.

Input and output reflections are independent of each other, at least from a certain complexity up. That is the point of an amplifier, to decouple input from output.

Rene

Try searching google for an app note from Motorola or HP on Small Signal Amplifier Design Linvill Method or some combination of those words.

What transistor is it? Doesn't the spec sheet give a bias point and input reflection coefficient (not a vswr circle) for optimum NF?

S12 is never 0. Design equations for simultaneous I/0 match are available.

Splitting hairs ? I said it was dependent on the complexity. A standard OpAmp with sufficient gain, sufficient feedback has no coupling between the two. It ideally has infinite input impedance, zero output impedance and with some external parts can be made to match whatever on both sides independently.

Sure, a single transistor looks a bit different.

Rene

I am only simulating it at the moment. I am going to use a Agilent ATF series PHEMT.

sthim2003

Not really.

He is likely talking about an RF/microwave preamp. He didn't mention an op-amp.

yeah, a "bit."