A Frequency Shift Technique for Pattern Correction in Hologram-Based CATRs

The measurement accuracy of a compact antenna test range (CATR) is limited by the level of spurious signals. At millimeter and submillimeter wavelengths the spurious signals are caused by range reflections and deformations of the range collimating element. Several antenna pattern and range evaluation techniques that can be used to mitigate the effects of these nonidealities have been published. At submillimeter wavelengths these techniques are typically time consuming or they are not able to correct the antenna pattern close to the main beam. The frequency shift technique does not have these limitations in a hologram based CATR. In this paper, the applicability of the frequency shift technique is analytically studied for a hologram based CATR. The technique is verified by measurements. The accuracy provided by the frequency shift technique is compared to that of the antenna pattern comparison (APC) technique