Research on OAM Wave Propagation Characteristics under Occlusion

In this paper, the occlusion propagation characteristics of orbital angular momentum (OAM) beams are studied based on the parabolic equation (PE) method. Two construction methods of OAM aperture field in PE are proposed, namely direct generation method and beam modulation method. The results show that the uniformity of the aperture field amplitude generated by the uniform circular array in the direct generation method is better than that of the rectangular array. The mode of the helical spectrum expands when the propagating OAM beam is blocked. Two forms of occlusion are discussed here. In both cases, as the occlusion range increases, the energy of the main mode gradually decreases, and the energy change of the extended mode has periodic characteristics, and the farther away from the main mode, the shorter the change period.