A Flexible Metasurface-Based OAM Focusing Antenna

In this paper, a flexible dielectric metalens OAM antenna with an antenna size of 117mm×117mm and a 13 by 13 unit is proposed. The unit cell consists of four layers of double-opening square ring patches surrounded by a substrate integrated waveguide, and is printed on two layers of flexible substrate with a layer of air gap between the two layers. By adjusting the element, we can compensate for the phase shift caused by the vortex wave propagating in the form of a spherical wave. The simulation results show that the lens can significantly reduce the divergence angle of OAM. It reduces the divergence angle of an OAM with a mode of -1 from 35° to 9°. Also increase the gain from 4.55dBi to 11.dBi, so that it can find the possibility of further application in wireless communication and microwave bioimaging.