Antenna Phase And Polarization Measurements In The Far Field

Antenna measurement is the key technology for developing antennas. The phase and the polarization of the antenna can provide us important information; the characters of the phase and the polarization are the important properties of some antennas to be test and designed, with the developing of phased arrays, Monopulse antennas, big interfermeters, Adaptive antennas, other new type antennas and the enlarged applications of polarization.We first summarize the existing methods and technologies for phase and polarization measurements of antennas, and then we introduce the theory and the process of the liner-polarization method for polarization measurements and the differential phase method for phase measurements. This lecture study methods to locate the position of the phase centre and the calibrations in the liner-polarization method for polarization measurements, and figured out a antenna measurement system which uses methods studied in this lecture according to the equipments we already have.There are three main works in this paper: First, we study the theory of the differential phase method and the system errors in it, we find a numerical method to calculate the position of the phase centre in the axis of abscissa by studying the phase center problems in the method. We can calculate the exact position of the phase centre in two dimensions with the known method to calculate the position of the phase centre in the axis of ordinate; it makes it more precise and convenient to locate the phase centre. Second, we establish a polarization distortion model through studying the liner-polarization method and its system errors, three calibration methods are put forward according to the different system error conditions in the liner-polarization method. Three calibration methods make the polarization measurement more veracious and flexible; we discuss the corresponding-space method thoroughly.We validate the two works through sets of experiments. The experiments we designed validate the validity of the method to calculate the position of the phase centre in the axis of abscissa. We also compare the three calibration methods in...