Design and Validation of an All-Dielectric Metamaterial Medium for Collimating Orbital-Angular-Momentum Vortex Waves at Microwave Frequencies

Abstract

Vortex waves have potential applications in wireless communication, because of their advantages in improving channel-transmission efficiency. However, the peculiar divergence of vortex waves seriously limits their propagation distance for communication. Thus the authors propose an innovative method for collimating vortex waves at microwave frequencies, based on transformation optics. Their all-dielectric device can reduce the divergence angle of vortex waves over a wide bandwidth, and collimate vortex beams with multiple modes.