Properties of Orbital Angular Momentum (OAM) Waves with Respect to Wireless Communication in Complex Environments and to Electromagnetic Interference

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The proposed project here aims to contribute scientifically in the area of wireless communication based on the Orbital Angular Momentum (OAM) property of electromagnetic waves in the lower part of the microwave spectrum (up to 10 GHz). OAM carrying waves have been explored and used in the past mostly in the optical regime. Only about ten to fifteen years ago utilization for wireless communication at “radio frequencies” started to be explored and is still being explored. While it could be shown during this time that OAM antennas are in principle equivalent to MIMO antennas and, hence, there is no real bandwidth advantage over existing technology there are still many open scientific questions related to OAM waves generation, propagation, and reception. Questions being explored in this project pertain both to the fundamental electromagnetic perspective (reflection, diffraction, scattering, shielding, superposition/interference etc.) as well as to the more applied communication engineering perspective (individual antenna choice, array design, mode isolation, impedance matching, useful range of distances, bandwidth considerations, behavior in complex environments and environments with aggressors etc.). To allow this, the project proposes a combination of numerical and experimental approaches. Numerical simulations will be performed an in-house tool based on the method of moments. In parallel, prototypes of OAM antennas will be designed and tested in an antenna measurement chamber at TUHH, the results of which will be compared to results of simulations for validation. The specific objectives of project are as follows: (1) Better understanding and description of fundamental electromagnetic properties of OAM waves such as reflection, diffraction, scattering, shielding, superposition/interference as well as behavior in complex environments leading to multi-path propagation. (2) Generation of guidelines for OAM antenna array design both with respect to the contribution from the individual antenna element as well as the contribution of the array design. (3) Quantification and evaluation of OAM based communication in complex environments and subject to electromagnetic interference. (4) Development of a measurement procedure for OAM antenna arrays and OAM based communication using an existing antenna measurement system at TUHH and validation of selected numerical results. We are convinced that the results of this project will also help to further elucidate the practical, engineering side of the question whether OAM based communication has the potential for a wider range of applications or not.