Theoretical Study on Estimation Accuracy of Phased-Array Calibration Using Beam-Steering Modes

This article theoretically clarifies the estimation accuracy of phased-array calibration using beam-steering modes. Beam-steering modes can be potentially employed to estimate the element field variations without interrupting the mission operation such as radar and communication, enabling the on-site calibration during it. However, its estimation accuracy depends on how to beam-steer. Our conducted theory suggests that an orthogonal set of beams is optimum in terms of the estimation accuracy and clarifies the lower bound of the estimation error due to additive white Gaussian noise (AWGN) and the element field fluctuations. Numerical simulations when using some typical beam-steering modes are carried out to demonstrate the estimation accuracy and validate our theory.