Improved Over-the-air Phased Array Calibration Based on Measured Complex Array Signals

This letter presents an improved phased array calibration method based on measured complex array signals with one single probe. All the phased array elements are excited simultaneously in the measurement, and only phase reverse of each element is required. The error on the first antenna element of the reference method is analyzed, which shows it is accumulated as the array size increases. One more measurement with designed element phase settings is introduced to overcome the deficiency. The improved method shows that only $N+1$ measurements are required to calibrate $N$ antenna elements accurately. Finally, a $4\times 8$ antenna array composed of 4-ridged horn antennas operating at 3.5 GHz was measured to validate the effectiveness of the improved algorithm.