Calculadora de Ganho de Antena — Formula
## How Parabolic Antenna Gain is Calculated
Antenna gain measures how effectively the dish concentrates energy compared to an isotropic radiator.
### Formula
**G = eta x (pi x D / lambda)^2**
**G(dBi) = 10 x log10(G)**
Where D is diameter, lambda is wavelength (c/f), and eta is aperture efficiency (typically 0.5 to 0.7).
The beamwidth approximation is **theta = 70 x lambda / D** degrees.
Antenna gain measures how effectively the dish concentrates energy compared to an isotropic radiator.
### Formula
**G = eta x (pi x D / lambda)^2**
**G(dBi) = 10 x log10(G)**
Where D is diameter, lambda is wavelength (c/f), and eta is aperture efficiency (typically 0.5 to 0.7).
The beamwidth approximation is **theta = 70 x lambda / D** degrees.
Exemplo Resolvido
A 1.2 m dish at 12 GHz with 55% efficiency.
- Wavelength: 0.3 / 12 = 0.025 m
- pi x D / lambda = 3.1416 x 1.2 / 0.025 = 150.8
- G linear = 0.55 x 150.8^2 = 0.55 x 22,741 = 12,508
- G dBi = 10 x log10(12508) = 40.97 dBi
- Beamwidth: 70 x 0.025 / 1.2 = 1.46 degrees