Orbital Angular Momentum Based Structured Radio Beams and its Applications

The vortex electromagnetic (EM) wave carring orbital angular momentum (OAM) that exhibits the phase distribution of the helical wave front. It is expected to provide a new dimension of the physical parameters for the multiplexing and manipulating EM wave, and bring a new opportunity to the traditional EMs. However, there are many obstacles in the practical applications in radio domain. We excavate out that the vorticity and orthogonality are the two essential characteristics of the vortex waves. Based on this, it is proposed to use vortex wave mode group to modify spatial structure and form structured EM beams. This kind of beams not only retain the inherent vorticity and orthogonality of the traditional OAM wave, but also avoid the inherent defects in the applications of the traditional vortex EM waves. In this chapter, the construction and manipulation of the OAM-based structured radio beams are investigated. The vorticity and orthogonality of this kind of structured radio beams are analyzed. Several antennas for the structured radio beams are designed, and the potential applications in the radar detection and wireless communications are envisioned.