Finding the amplitude illumination distribution and scattered pattern formed from any type of Sub reflector

A theory for finding the Amplitude Illumination Function and Scattered pattern formed from any type of Sub reflector of the Antenna has been developed. The Amplitude Illumination distribution formed over the aperture of the Main reflector from the Sub reflector is required for proving the correctness of the design of the Sub reflector. Till now there is literature on finding the scattering pattern of the sub reflector from the technique of vector diffraction theory which is complex procedure. This paper presents easiest way to find the scattered pattern and Illumination distribution by using the technique of path loss based on geometric optics. The analysis is made with the help of Laws of optics mainly the Snell's Law of Reflection.