1. Antenna diameter: Diameter of parabolic reflector antenna is referred as antenna diameter. It is denoted by 'D'
2. Antenna efficiency: Antenna efficiency is the ratio of input power to the radiated power of the antenna. It is denoted by 'h'. The value of 'h' lice between 0.55 to 0.73.
3.Antenna gain GT: The isotropic power gain of the antenna, GT, is defined as the power density in the maximum direction, denoted here by PD,to the power density archived by a 100% efficient isotropic radiator.
PT is the total power radiated.
Antenna gain in GT = 10 log (p2D2h/(l2*100))
= 10 log (p2D2h/((C/f)2*100))
=10 log (p2D2h/((3/10*f)2*100))
=10 log (p2D2h/(3/f)2)-----(dB)---
Example Calculation of the gain of a 3.80-m parabolaidal antenna operating frequency of 6.175 G Hz & aperture efficiency of 0.55