Characterizing Frequency Dependence of Calibration Coefficients for Antenna Arrays

Reduction of calibration points in frequency be-comes important as wideband arrays are increasingly used in various applications. Determination of direction of arrival (DoA) of the incoming signal can work as an effective instrument to verify calibration performance on antenna arrays. We employed a software-defined radio (SDR) system, which supports multiple channels, to measure difference in phases and amplitudes among the receiving channels in the antenna array, and calibration co-efficients were derived accordingly. Multiple signal classification (MUSIC) algorithm was then applied to study performance in de-termining direction of arrival when frequency was shifted around the frequency of calibration. The experimental results indicate that the calibration coefficients were valid for the frequency range of 1 MHz when the angle of arrival determination had an accuracy within 5 degrees.