# S-Parameters Power amplifier impedance matching

I recently decided to conceive a 10W class 446MHz amplifier.

I want to be able to amplify a 100mW signal into a 10W, for that i'm going for a two stages amplifier :

SKY65162 to amplify the signal to 1W Then a 2SK3075 to reach 10W approx. Datasheets :

The first amplifier is very well documented in the datasheet, but the second is more tricky. I have this datasheet which describes partly the circuit to make use of the transistor :

Schematic recommended by the manufacturer This schematic is supposed to describes the circuit required to function at around 500MHz. I was going to use theses values but I thought i could use the S-Parameters provided by Toshiba to make the impedance matching at the input and output.

I've bee searching through internet, lot's of publication, white papers. I even reopened my engineering books to find absolutely nothing.

Toshiba S-Parameters :

VAR        vds = 16.0

VAR        id = 0.500

!          REM     DATA    NUMBER = 56

BEGIN      ACDATA

#          HZ      S       MA      R            50

% F        n11x    n11y    n21x    n21y    n12x    n12y    n22x    n22y

450000000  0.880  -173.1   1.546    60.6  0.0193   -22.5   0.817  -176.5


Questions:

• Is this even possible?
• Does anybody could recommend me a document / method to do this?
• Electronics amateur question: Are those polynomial based filters on the input and output ? Then some traps ? I suppose the purpose is to remove unwanted harmonics and only test a clean sine wave. If yes, then I think your question means, "Is there a setup of filter coefficients that will also provide an impedance transform?" Am I even close ?
– wbg
Jan 19, 2022 at 18:59
• How about adding a feed back network to the transistor to boot strap it into a match??
– wbg
Jan 19, 2022 at 19:06
• To be honest I'm a young EE who studied RF components. And I don't know at all those way of doing an impedance match. I don't think those are polynomial filters. But if we forget the rectangular resistor which looks like phase shift length of transmission line, those passives around the transistor doesn't look like an impedance matching circuit... So I'm stuck. Jan 19, 2022 at 22:04
• I'm looking forward to one of the EE people here to chime in. If the boxes are transmission-line segments, then wouldn't they affect phase and thus impedance ?
– wbg
Jan 19, 2022 at 22:18
• Yes it may very well be the case, it would act as distributed inductors. Jan 19, 2022 at 22:31