In the context of antennas, what does "gain" describe?

Gain in the context of antennas refers to the ability of an antenna to direct or concentrate radio frequency energy in a specific direction, resulting in an increase in signal strength in that direction compared to an isotropic radiator, which would uniformly distribute energy in all directions. This directionality improves the effectiveness of the antenna at transmitting or receiving signals, making it valuable in various applications such as communication systems and broadcasting.

Antennas with gain are designed to focus energy rather than radiate it uniformly; thus, when an antenna has a gain of a certain number of decibels (dB), it indicates how much stronger the signal will be when directed towards a specific target area compared to an antenna without gain. The term is crucial in evaluating how well an antenna will perform in its intended application, making it a fundamental concept in antenna theory and engineering.