Compact range interaction with a large millimetrewave antenna

A compact antenna test range (CATR) was established at Marconi Command and Control Systems Ltd, Frimley, in the autumn of 1987. The majority of the equipment was of proprietary origin. Its first principal role was the measurement of a high gain precision radar tracking antenna designed for operation within the 33 to 36 GHz frequency band. It soon became apparent that the interaction between the CATR and this antenna was excessive and was readily manifest as a ripple on the measured elevation pattern. This had a spatial frequency that was incompatible with the electrical size of the antenna. The paper is concerned with the identification of the problem, and the means adopted for the elimination of the effect from the test results