Generation of OAM Beams Using Phased Array in the Microwave Band

TLDR

OAM‑carrying beams enable novel information‑rich radar paradigms and other applications. The study proposes a microwave‑band system that generates high‑order vortex EM beams at X‑band for the first time. The authors design a uniform circular array–based OAM generator, develop a signal model, incorporate array‑error terms, and run numerical simulations to assess amplitude and phase error impacts on the radiation field and vortex imaging. Experimental results confirm that the system produces high‑quality vortex beams that match simulation predictions.

Abstract

A system is proposed to generate vortex electromagnetic (EM) beams in the microwave band, which generates high-order vortex beams at the X-frequency band for the first time. First, the orbital angular momentum (OAM)-generating system is designed and the signal model based on the uniform circular array is presented. Subsequently, the mathematical model with array error contributions is established and, comprehensively, numerical simulations are conducted to analyze how amplitude and phase errors affect the radiation field and the EM vortex imaging. The experimental results validate that the proposed system can readily generate vortex beams of high quality, which are in agreement with the simulated results. The work paves the way to applications of OAM-carrying beams as well as a novel information-rich radar paradigm.