Efficient Calibration of Very Large mm-Wave Radars by Virtual Phase Center Analysis

Abstract

Manufacturing uncertainties, antenna coupling, and other hardware imperfections lead to a deviation of the real hardware behavior from the ideal one. Calibration procedures aim to determine the deviation between the ideal signal model and the real hardware behavior to achieve an improved measurement accuracy of the array. When using large apertures and large modulation bandwidths, the measured distance of a single target at different receive antennas depends on the incident angle. Furthermore, the far-field condition cannot be met. In this paper, the influence of these errors on the calibration is analyzed and a strategy to correct these errors by signal processing is derived. Additionally, we propose a method to reduce the calibration effort for large aperture radars based on the a-priori knowledge of the array geometry. Experimental results with an imaging radar at 150 GHz demonstrate the efficiency and accuracy of the proposed error correction method and the related calibration concept.

Highly Efficient Calibration of Antenna Arrays by Active Targets in the Near-Field

“…Particularly for large-aperture sizes, the calibration effort increases drastically [14]. Therefore, enhancements in calibration techniques are needed to obtain accurate antenna array models with low measurement effort during the calibration procedure [16], [17]. A typical calibration setup is sketched in Fig.…”