Simulation of the RCS Measurements of a Conductive Disk in a Tapered Anechoic Chamber with a Lens

Simulation of measurements of the scattering characteristics of a reference object in the form of a flat disk in a low-frequency tapered anechoic electromagnetic chamber with a lens has been carried out. Two lens collimators are considered: a conventional hyperbolic lens and the same lens coated on both sides with a matching layer optimized for the frequency of 600 MHz. The contribution of the nonuniformity of the field distribution in the quiet zone of the chamber to the measurement accuracy of the radar cross section of the object has been investigated. It is shown that the collimator with the lens coated with the matching layer provides higher accuracy in measuring the radar cross section of the disk in the side lobes of the scattering pattern due to providing lower nonuniformity of the field amplitude distribution in the quiet zone of the chamber. The influence of re-reflections between the lens and the disk on the accuracy of its radar cross section measurements has also been investigated. It is shown that the lens coated with the matching layer reduces the effect of re-reflections not only at the frequency of matching but also in a sufficiently wide frequency range.