Parabola antenna is commonly used in satellite communication.
The gain of parabola antenna \(G\) can be written as:
\[G = \eta\left(\frac{\pi D}{\lambda}\right)^2\]
where \(D\) is the diameter of the antenna, \(\lambda\) is the wavelength, and \(\eta\) is the aperture efficiency (\(0<\eta<1\))