The additional power that is added to the transmitter power
The additional power that is required in the antenna when transmitting on a higher frequency
The increase in signal strength in a specified direction compared to a reference antenna✓Правильный ответ
The increase in impedance on receive or transmit compared to a reference antenna
Объяснение
Gain describes how much stronger the signal is in a chosen direction than it would be from a reference antenna fed with the same power, so it is a redistribution of power rather than an addition of it. An antenna cannot add power to the transmitter output.