maximum power - RF Cafe Forums
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Post subject: maximum power Posted: Thu Dec 14, 2006 11:36 am
Joined: Tue Nov 14, 2006 7:21 pm
can you tell me various design consideration for getting higher power for the power amplifier?
how should i increase the power of amplifier?
Post subject: Posted: Thu Dec 14, 2006 4:30 pm
Joined: Mon Jun 27, 2005 2:02 pm
One possibility to increase the output power is to match the power amplifier to maximal output power. You have to match the output to the conjugate of the output impedance. This however might come on the expense of other design paramaters like linearity or effieicncy.
You can do Load-Pull measurements. This can be done with a Tuner or by using a CAD tool e.g. ADS. The simulation results are countours of points on the Smith Chart, which correspond to different output power levels. This indicates to which impedance the output has to be matched in order to obtain a certain output power. You can also do paramater sweep: frequency, bias point to see how the output impedance changes and according to that to synthesize the required matching network. In ADS for example, you can get the contours for several paramaters like ACPR, IMD, output power etc, and you can design a matching network to a certain impedance which is a trade-off between several paramaters - the intersection of several countours.
Hope this helps!