Numerical investigation of orbital angular momentum density of antenna arrays based on the method of moments

In this contribution antenna arrays that radiate electromagnetic fields showing orbital angular momentum (OAM) are being studied. We investigate the spatial distribution of normalized OAM densities on hemispheres for two types of circular dipole antenna arrays operating at 100 MHz both in free space and close to an electrical conducting plane, respectively. Comprehensive simulations were performed based on the Method of Moments (MoM) and an explanation of the generation of OAM based on fields is given. To the knowledge of the authors similar studies have not been performed before. The results show that OAM density is a highly complex quantity and further research is necessary to exploit OAM in radio communication and to understand its potential for and susceptibility to electromagnetic interference.