The Study Of Antenna Near-field Measurement System Based On Network Analyzer

The theory and technology correlative with network analyzer in the antenna near-field measurement system are deeply studied in this dissertation. The content is composed of the accuracy analysis of a network analyzer which is in good performance, the automatic measurement of amplitude and phase signal by controlling network analyzer through a remote computer and the configuration of the antenna near-field measurement system which utilize this type of network analyzer as its receiver.Firstly, as the basis of this dissertation, the basic theory of planar near-field measurement is elaborated. The theory of plane wave spectrum expansion on the electromagnetic fields produced by antennas is discussed and the expressions of antenna far-field pattern are given. The antenna far-field patterns determined from planar near-field data are derived and the formulas transforming the near-field into far-field in the case of considering probe compensation are given. The choice principles on the sampling interval, the width of the scanning plane and the distance between the aperture plane of the antenna under test and the scanning plane are discussed.This dissertation then presents the system performance of a high effectively network analyzer utilized in antenna near-field measurement system and shows the comparison on accuracy between the analyzer and another type of analyzer. The methods of improving measurement accuracy and reducing system errors of network analyzer are described. The way of controlling analyzer through a remote computer based on GPIB interface is also discussed deeply. On the basis of experiments and the actual configuration of antenna near-field measurement system, it can be concluded that the antenna near-field measurement system described in this dissertation has the high dependability and repeatability.