How to match power dependent Impedance (large signal)

[ICRF]

Hello,

is there a better way to match a power dependent impedance on an IC? The matching changes the power transfered to the transistor connection and therefor the transistor changes its impedance. I use Cadence Virtuoso and hb + hbsp to get the impedance of the transitor port, because a large signal analysis is needed.
Is it helpful to somehow add a resistor so that the impedance does not change so much?

Best regards

 

[BradtheRad]

Incandescent bulbs change their own resistance depending on how much power they consume. The filament develops greater resistance as it lights up brighter from red to yellow to white.

Example, the Wien Bridge oscillator often makes use of a bulb for the above reason, to regulate amplitude and shape of a sine wave.

Diodes and LED's change their own resistance depending on how much power they consume. The Voltage versus Amperes graph is non-linear.

 

[dick_freebird]

OK, so Zin changes.

Does that affect anything that matters? Or is it
just "something to expect, and fit up"?

A BJT's input impedance changes big time but
a switching application does not care, just
feeds it what it needs to swing the load or
feeds it nothing (maybe pull a little back out).

At 50ohms many devices' Zin is a trivial
subtraction. And in those kinds of systems
the frequency response is a likely care-about
and series R is not your friend (unless you
are after an inferior input low-pass filter
effect, with added thermal noise).