Excitation Faults Detection in Relatively Large Planar Array Antennas, Measured in Short Antenna Ranges

An effective algorithm for detection and correction of excitation errors in the aperture of relatively large planar array antennas, measured in short antenna ranges (Fresnel distances) is presented. The method comprises a measurement of a quasi far-field radiation pattern of the antenna under test (AUT) at a Fresnel distance, a derivation of a distorted magnitude/phase excitation of the array antenna, an application of a correction on the distorted array excitation and estimation of the actual array excitation. The accuracy of the method improves as the directivity of the AUT gets higher. The method is applied for detection of deliberately introduced excitation errors of an X-band planar array antenna and the measurement results are presented and discussed.