Analysis of 3-D images generated by hierarchical disaggregation

An accelerated method for generating fully-polarimetric 3-D images of an arbitrary current distribution in free space is described with special emphasis on the inherent point spread function. The image generation is operating on the data obtained by sampling a far-field radiation pattern over a certain bandwidth. The idea is to accelerate the coherent summation of the fully-polarimetric plane wave spectrum by a hierarchical disaggregation inspired from the Multi-Level Fast Multipole Method. The resulting images reveal anisotropic distortions when compared to the source distribution, where the distortions originate from the non-radiating part in the source distribution. The effect of these distortions on the image quality are investigated by analysing the point spread function.