| Efficiency (η): | |
| Wave Length (λ): | |
| Physical Aperture Area (A): | |
| Antenna Gain: | |
GdBi = 10 LOG10 ( η4πA / λ2)
Where λ = Wave Length, η = Efficiency, A = Physical Aperture Area
In electromagnetics, The antenna gain is very useful, it combines the antenna's directivity and electrical efficiency. To a receiving antenna, the gain means how well the antenna converts radio waves, To a transmitting antenna, it means how well the antenna converts input power into radio waves.