Basic design principles of electromagnetic scattering measurement facilities

Typical experimental configurations that are used for measuring radar scattering are analyzed with simplified forms of basic electromagnetic principles to show how the experimental facility design affects measurement capability and the accuracy of the measured results. The discussion includes effects of a nonuniform field over the model space, the measurement distance from the scattering model, multiple reflections from walls of a chamber or from nearby objects, interference from model support structures, and the effects of forward scattering. Guiding principles are developed for choosing and designing the important components of a scattering measurement facility such as the transmit/receive antennas, the RF power sources, model support structures, and transmission line component assemblies so that measurement accuracy is maximized. Simple experimental procedures are given for evaluating a given measurement setup. Emphasis in the report is placed on illustrating the principles with numerical examples.