Antenna Gain Calculation

 

The antenna gain is calculated as follows:

 

Ant Gain = 4 x PI x 'efficient area' = dBi

                 -----------------------------

                    wavelength (lamda)

 

PI = 3.1415927 approx

 

'efficient area' = antenna reflector area x antenna efficiency

 

Antenna efficiency is the ability of the antenna to radiate all of the power fed into it. An efficiency of 100% is theoretical but in practice not achievable. The average efficiency of an antenna is in the region of 70%, but often 60% is used as a worst case figure.

 

 

 

70% means that 30% of the input power is lost and this is due to factors such as mismatch, reflected power and imperfections. A reflector is not always a perfect reflector.

 

wavelength =  Speed of Light =   3 x 10^8

                       ------------------      --------------

                           frequency          frequency