On the Use of Spherical Harmonics in Sparse Microwave Imaging

In this paper, we introduce a novel microwave imaging method using spherical harmonics and the sparse processing. As the sources of the spherical harmonics, we use the multipoles of different order. Based on theoretical considerations and as shown by numerical examples this approach is capable of retrieving concave shapes, which is particularly interesting when imaging complex-shaped targets. In this paper, we limit ourselves to the utilization of the multipoles parallel to the z-axis. We implement rigorous analytical expressions describing the first three multipole orders to improve the method's accuracy. As a test bed we analyze a centered and an offset star-shaped object in the presence of noise. For such a meaningful case, satisfying results have been obtained.