Technologies Of Error Correction In Near Field Measurement

The dissertation is aimed at the correction method on ultra-low sidelobe antenna performance aroused by amplitude and phase random error and finite scanning truncation error as the planar near- field scanning technique is used.At first, the background and actuality of antenna near- field scanning measurement is introduced .The basic theory and correlative knowledge of near-field measurement is given. Then the expression of sidelobe measurement errors versus the relative parameters of antenna under test (AUT) and near-field amplitude and phase random errors are presented. And amplitude and phase random error and finite scanning truncation error is . analyzed. The error-upper-bounds expressions of antenna pattern errors resulted from the finite scan truncation errors. Then, the effect of the amplitude and phase random errors and the finite scan truncation errors in the near-field measurement on the sidelobe of ultra-low sidelobe antenna patterns are simulated by computer simulation method. This method makes a good result. It proved that error analysis method based on Near Field-Far Field Transformation is applied at large. Finally, the effective methods for these two error sources to be reduced are put forward in the way of Frequency-domain, then "method of average" which is used to correct amplitude and phase random errors and the method without expanding the scanning plane showing by weighted function and fractional Fourier transform for reducing the finite scan truncation errors are made with computer simulation. It proves that they are the effective methods of correction in the area of near field measurement.