Generation of Continuously Variable-mode Orbital Angular Momentum Beams

Abstract

Orbital angular momentum (OAM) beam emitters with compact structure and high performance are highly desirable for wireless communication and radar technology. Here, we propose a compact emitter that only consists of a ring resonator and a feed line. Continuously-variable-mode OAM beams are generated by adjusting the wavelength and transmission path. The basic design principle and specific evaluation index are discussed. Both the simulated and experimental results demonstrate that the proposed emitter obtains the capacity of generating variable-modes. This approach opens a way for designing novel OAM beam emitter with desired properties.

Design of Orbital Angular Momentum Antenna Array for Generating High-Order OAM Modes

“…Based on the work of [19], we have designed and optimized a ring resonator-based patch antenna element as depicted in Figure 1, which is capable of generating OAM beams with mode l = −1 or 1. The sign of the beam is determined by the rotation direction of the surface current.…”

“…The input feed signal oscillates in the ring resonator in which the new incident signal at the same working frequency resonates with the existing signal, while the signal oscillation at different frequencies is weakened due to the existence of phase difference. Therefore, the patch antenna based on the ring resonator has selective frequency characteristics [19]. Simultaneously, through the transmission of electromagnetic waves within the ring resonator, a continuous phase variation is formed within a range that is an integral multiple, which is a necessary condition for generating OAM beams.…”