Fast antenna characterization via a sparse spherical multipole expansion

Reliable spherical antenna characterization at high frequencies requires a considerable amount of time and often leads to the inefficient use of measurement facilities. The proposed method cuts the number of necessary samples for spherical antenna scans by 75% as compared to standard techniques, thus enabling significantly faster scan times without significant loss of accuracy. This is achieved by enforcing sparsity in the spherical multipole expansion through suitable translation and rotation operators. In this context, a novel and accurate method for phase center estimation is established which relies on a 1-norm minimization. Further, an iterative reconstruction algorithm is introduced which allows for reconstruction of undersampled measurement data in a successively optimized coordinate system. Validation using both synthetic and real measurement data demonstrates the capabilities of the proposed method.