Post subject: please reply---output match in PA Posted:
Sun Jan 08, 2006 2:22 am
i know i've been asking a few questions
and i really appreciate all the answer....i'm a student learning
and i've one more question to ask.
i did loadpull analysis
and i found out that I need a load of X+jY. so what i did i just
transformed a 50 ohm load to X+jY using the matching utility in
ADS and it seemed to work. now when i put it in the circuit it doesn't
match all that well. when i am running s-param simulation i terminate
in 50 ohms since i'm transforming 50 ohms to X+jY, right? if not
please explain how a match can be verified for optimal load match?
Just wanted to make sure. the thing that is confusing me is that
the output is taken from the collector and there is a certain output
impedance....if you were doing the usual conjugate match then it
is clear to me but here it's not conjugate match but instead the
transistor needs to see a certain load (X+jY) and i do that by transforming
50 ohms to this X+jY value...because of this i don't understand
what the output reflection coefficient is calculating or reprsenting??
the thing is if i try to tune the components of output match in
ADS then this would eventually lead to "conjugate match" and not
a match to X+jY because as I said the output is connected to collector
and after a matching network is terminated in 50 Ohms.
the way i did output match was to take the X+jY impedance and then
do the usual standard method of matching 50 ohms to X+jY...this
is how you do it, right? please reply, your help will be very much