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Difference between impedance matching and power matching

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wajahat

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Hi all,
i want to know whats the difference between impedance and power matching in circuits. I doubt that they are same.

Thanking all in anticipation.


regards
 

they are different!
impedance maching could be for power, linearity, BW, or gain, and so on.
 
If you look just to the definition of the impedance matching you see that the impedance matching is necessarily to get the maximum power transfer.

Impedance matching can affect the gain, noise, output power, linearity, etc, but these are just results of how it behaves a component when input/output impedances are different than optimal.
 

Impedance matching = Minimizing reflections and maximizing gain

Power Matching = Optimizing the load line your power amp sees

Consider a common transistor amplifier with the output taken off the drain (or collector). The IV curves are very flat. Matching these to 50 Ohms would require transforming 50 Ohms to a high impedance (yielding bookoo gain, but very little saturated output power). However, maximum output power is obtained by getting the load line to swing symmetrically between cutoff and saturation, making the optimum load resistance to achieve maximum output power roughly Vdsq/Idsq (or Vceq/Iceq). At high frequencies many other factors start to rear their ugly heads, but this should illustrate the starting point.
 
Hi,
I'm currently designing a UWB patch antenna using CST MWS. I got all the results i want such as S11,radiation pattern etc. The line impedance of my antenna also got 50 ohms. But what is confusing me is the smith chart not all 50 ohms at my desired frequency (3.1 - 10.6 GHz). Is smith chart still important since i already got 50 ohms at line impedance? And what would happen to the fabricated antenna if the smith chart not 50 ohms?
 

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