Parallel Calibration Method for Phased Array Based on Multiple-Period Time Modulation

A novel parallel calibration method was proposed and verified for phased arrays, by modulating phase shifters of multiple channels with multiple periods. After periodic phase modulation, the amplitude and phase mismatches can be calculated out through analyzing the generated harmonics in the composite signal. Compared with the existing method, two major advantages for the proposed method are as follows. First, the requirement for the dynamic range of the receiver is reduced, improving the calibration accuracy with the same signal-to-noise ratio. Second, the number and position of simultaneously calibrated channels can be flexibly selected. Besides, only one measurement is required to obtain all channel mismatches. Its main computation concentrates on the discrete Fourier transform for several harmonic components. Numeric simulations were provided to verify the effectiveness of the proposed method. An S-band 8-channel phased array was fabricated and tested to examine its performance and accuracy, acquiring root-mean-square-errors of 0.52 dB and 2.41
$^\circ$
in amplitude and phase, respectively.