The use of statistical image classification techniques in antenna measurements

It is a well know limitation associated with planar near field measurements that the finite extent of the scan plane restricts the size and nature of antennas that can be successfully characterised in a planar facility. At DERA Funtington a partial scan technique has been developed that overcomes some of these difficulties. Individual data acquisition scans of the antenna that, of themselves, are not sufficiently extensive to satisfy the requirement that the data be periodic over the sampling interval, are combined to produce a composite scan. The size of this composite scan being such that it is extensive enough to produce a usable near field data set. The accuracy of these composite measurements has, in the past, largely been judged by inspection however the authors have developed an objective measure of the accuracy and repeatability of the measurements. This paper illustrates the measurement process and the techniques associated with statistical image classification used to confirm its accuracy and repeatability.