Error-Theory Analysis And Correction For Ultra-Low Sidelobe Array Antenna

The dissertation studys the effects on antena performance index aroused by several main error sourses and corresponding correction method when near- field scanning technique is used .At first, The background and actuality of antenna planar 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 the error spectrum aroused by amplitude and phase measurement is analysed. The error-upper-bounds expressions of antenna pattern errors resulted from the finite scan truncation errors, multiple reflection errors produced by probe and AUT and room scattering errors in the near-field measurement are derived respectively. 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 firstly adopts fewer line arrays and makes a good result.It Proves that error analysis method based on Near-Field-Far-Field Transformation is applied at large. Finally,the effective methods for these four error sources to be reduced are put forward in two ways of Time-Domain and Frequency-domian, then "method of average" which is used to correct amplitude and phase random errors and the method of expanding the scanning plane for reducing the finite scan truncation errors are madewith computer simulation. It proves that they are the effective methods to correct the near field measurement.