UCA Based OAM Beam Steering With High Mode Isolation

Abstract

In the case of uniform circular array (UCA) based Orbital Angular Momentum (OAM) communications with misaligned transceivers, beam steering is needed to overcome the performance deterioration. To keep the vortex characteristics and the mode isolation of the steered OAM beam, we propose a Hybrid Position Phase Beam Steering (HPPBS) scheme in this letter. For the target deflection angle <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\theta,\phi)$ </tex-math></inline-formula> , the deflection of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta $ </tex-math></inline-formula> is achieved through the phase adjustment and the deflection of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\phi $ </tex-math></inline-formula> is realized through the antenna position adjustment. The theoretical analysis shows that a quasi-ideal OAM beam of the given direction is generated using our scheme. In order to make the scheme feasible, we propose to deploy it on a planar phased array. Simulation results indicate that compared with the existing OAM beam steering scheme, our HPPBS scheme can flexibly adjust the directions of OAM beams while maintaining high isolation among each OAM mode.