A new calibration algorithm for smart antenna arrays

Antenna array is essential to perform many array signal processing algorithms such as direction of arrival estimation, constraint beamforming, and vector channel sounding. Usually array calibration is performed by calculating a correction matrix from calibration measurements, which compensates gain and phase deviations and mutual electromagnetic coupling effects between the antenna elements. The investigation of microstrip antenna arrays has shown that radiation emitted or received from substrate edges may also disturb the array performance severely. This effect can not be compensated by the correction matrix algorithm. Therefore an extended calibration model has been proposed and used in a laboratory environment. In this paper, a new and efficient algorithm to determine the parameters of this extended calibration model in a mobile communication system environment is presented and discussed. Finally, measurement results of an experimental smart antenna array system are presented.