Localization of Defects on Large Antennas Utilizing Sparsity and Spectral Filtering

Reconstructed equivalent currents on the surface of an antenna under test (AUT) can indicate local defects of the antenna structure. An accurate analysis of electrically large AUTs commonly requires a large number of potentially redundant measurement samples causing prolonged acquisition times. We combine the prior knowledge of sparsely localized defects with the pronounced directivity of large antennas. Employing local basis functions, the difference of the equivalent sources of the AUT with and without defects can be expected to be sparse. Cognizant of the large directivity of the AUT, we additionally employ spectral filtering of the radiated far field in the reconstruction process. Measurement results indicate the potential to significantly reduce the required number of samples while retaining reasonably accurate diagnostic information. A reduction of the number of measurement samples from 16 960 to 3000, i.e., by more than 80 percent, has been achieved with a real-world setup.