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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.
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 required