Surface Tolerance Analysis of offset Reflector Antenna in Ku-Band

This paper describes the surface tolerance analysis of 3m offset reflector antenna. The radiation pattern performance degradation (gain loss) due to surface tolerance/roughness is analyzed at Ku-band (high frequency or short wavelength). Compared the gain loss variation with respect to rms surface error by using the Ruze's equation and CAD simulation. Ruze's equation states that the antenna gain is inversely proportional to the square of the RMS surface error. The gain loss is increase drastically over rms surface error of 1mm. Analyzed the gain loss over the range of RMS surface error varying from 0.5mm to 5mm. The objective of the paper is to the analyses the effect on radiation pattern (Gain Loss, Side Lobe Label (SLL), Cross-polarization) due to the surface roughness/tolerance of 3m offset reflector at Ku-band and define the fabrication tolerance within the acceptable RMS surface error for manufacturing. Surface roughness error has been analyzed as considering two realistic approaches: RMS error variation analysis on 3m offset reflector and RMS error variation analysis on the three different zones (section) spaced at 1m of 3m offset reflector parabolic antenna.