Large-Scale Phased Array Calibration Based on Amplitude-Only Measurement With the Multiround Grouped-REV Method

There has been growing interest in employing phased array systems with large-scale array configurations in the cellular, satellite and automotive applications. Array calibration is essential to ensure phased array beamforming performance. The amplitude-only calibration methods, which only require amplitude measurement, are highly attractive especially when phase measurement is unavailable or unreliable. One of the most widely applied method is the rotating element electric field vector (REV) method.However, it becomes more sensitive to noise when the element number of the array under test (AUT) increases, making it unreliable for large-scale phased array calibration. In this work, a novel amplitude-only calibration method is proposed for large-scale phased arrays when the signal-to-noise (SNR) condition in the measurement is low. The basic idea is to divide the AUT elements into several groups and to perform the group-wise REV operations of the AUT in multiple rounds. Numerical simulations and experimental results have validated the effectiveness and advantages of the proposed method in calibrating large-scale phased arrays over the classic element-wise REV method.