TABLE OF CONTENTS Manuel Sierra-P rez and Manuel Sierra-Casta er
This chapter presents the antenna array calibration process for the DOA applications. The first part of the chapter studies the calibration of unknown phase and unknown gain in the antenna elements, and the effects of the coupling between the antenna elements (i.e., the coupling in the radio frequency circuits and the free space between the antenna elements). The last part of the chapter shows one example of the application of this calibration procedure.
Antenna array calibration has been a very active and interesting area of research in antenna array processing for the past several years [1 8]. For DOA applications, calibration of high accuracy antenna arrays becomes necessary to achieve adequate results, while the assumption of knowing a priori antenna array manifold is rarely satisfied [9]. Therefore, the combined effects of the unknown gain, the unknown phase, and the mutual coupling, as well as errors in the sensor positions, will degrade the performances of the antenna array processing algorithms [10]. The effects of mutual coupling become particularly important in antenna array calibration. These effects are widely studied for the DOA estimation in [11, 12]. The problems of the DOA and the steering vector estimation using the partially calibrated antenna arrays, and the problem of self-calibration of antenna arrays are also studied [13, 14].
