Fast and Accurate Near-Field Calibration Method for Phased Array Antennas

The near-field calibration can be performed indoors, avoiding to be affected by the environment and security concerns which makes it has important research value. Nevertheless, the application is limited by the calibration efficiency and precision. A near-field calibration method based on code division multiple-Access (CDMA) scheme is proposed in this paper to decrease calibration time and improve the calibration precision. In the proposed method, the calibrating signal associated with each antenna is distinguished by a unique spread-spectrum code sequence instead of the continuous wave (CW). The relationship between calibration accuracy and signal to noise ratio (SNR) is obtained by derivation, and the simulation results verify the correctness of theoretical derivation results. If the SNR is higher than 15dB, the calibration accuracy of the amplitude/phase can reach 0.1 decibel (dB) and 1 degree (deg), respectively. The proposed method can be good applied to the large-scale phased array antennas calibration.