Wireless Power Wiki

If you hear the word 'power gain', you justly interpret this as the ratio of the output power $P_{out}$ to the input power $P_{in}$:

$$ gain=\frac{P_{out}}{P_{in}}$$

Unfortunately, confusion is possible, since there are different ways to define the ouput and input power. And depending on which definition of power you use, you get another value for the gain. But mankind has found a solution: we use different names for the gains, depending on which power is considered. Let us try to give an overview of the three most common gains.