Research Of Phased Array Antenna Near-field Measurement Technology And Its Application In Engineering

The planar near-field measurement (PNFM) is an important testing method for phased array antennas. Its main functions have phase compensation, amplitude determination and array diagnosis of near-field for the phased array antennas. This system is commonly made up of scanner frame, microwave instrumentation, servo-control equipments , near-field software and testing probes.Precisions of antenna PNFM are influenced by many factors. Newell put forward eighteen items of errors for antenna PNFM. According to the reason which produces, these errors can be divided into four groups:emerging by theory and numerical calculation, by the instrumentations and equipments, by environment and by the probes. From engineering visual angle in this paper, the errors that greatly affect PNFM precisions are analysed, feasible engineering methods for heighten precisions are given.The testing probe is important part of the near-field measurement system. For both near-field and aperture field test, the probe must be made influence as small as possible for the field of tested antenna. This advances high requirements for probe design. In this paper balance feed and impedance matching on probe design are mainly discussed, matters needing attention in engineering use and a number of feasible ways are also expounded.On the basis of batch process requirements for a type of phased array antenna, the near-field transmission phase compensation, difference beam testing, null depth calculation and big sampling space are researched, and true feasible engineering ways that resolve above problems are given.