High-precision measurements on a compact antenna test range

A comparison is presented of results of antenna measurements on a compact antenna test range (CATR) with those on an outdoor range. It is determined that direct uncorrected CATR measurements are reliable, mainly due to the excellent phase characteristics of the CATR and the very low levels of stray radiation in the test zone of the anechoic chamber. It is shown that the uncorrected CATR data can be interpreted directly (beam width, gain, sidelobe levels, and x-pol) in antenna design and diagnostic methods. It is also shown that a powerful correction algorithm can be applied for measurements of oversized antennas where the test antenna occupies more than 50 percent of the aperture of the CATR (in linear dimensions), or for high-performance measurements. This algorithm is found to converge very fast, and there is no need to handle the complete plane-wave spectrum of the antenna but only the deviations of the CATR field spectrum.