A UNIST research team has proposed a communication device technology that can rapidly distinguish these OAM signals using a self-designed metasurface, raising expectations that it will accelerate the commercialization of 6G communication.

Professor Lee Jong-won's team at UNIST announced on the 22nd that they have developed a new communication device technology that will accelerate the commercialization of 6G communication.

It is a technology that utilizes a proprietary metasurface to generate and rapidly receive orbital angular momentum (OAM) signals, which are next-generation radio resources for 6G communication.

Professor Lee said, “Metasurface is a material designed to control the characteristics of radio waves, including light. The characteristics of light that can be controlled vary depending on the shape and arrangement of the two-dimensional structures placed on the surface.” "It was designed to simultaneously perform the roles of an OAM signal generator and receiver, and has been experimentally verified, which will help in the commercialization of OAM-based 6G communication technology," he explained.

Communication technology utilizing the physical quantity called OAM of light (radio waves) is considered a technology capable of efficiently using frequency resources.

This is because multiple orthogonal signals can be generated within the same wavelength (frequency) depending on the number of phase twists (OAM modes).

Thanks to this, the amount of data that can be transmitted at once can be increased, enabling faster communication.

On the other hand, unlike the beam used in general communication (Gaussian beam), OAM is characterized by a weak central beam intensity and strong intensity in the surrounding concentric regions.

For this reason, as the number of modes increases, the concentric circles spread out widely, requiring the size of the receiving antenna to increase, and it is also difficult to quickly separate and recover multiple incoming signals from the actual receiving antenna.

The research team proposed a communication device technology capable of rapidly identifying these OAM signals by utilizing a self-designed metasurface.

This metasurface can generate two types of OAM modes in the E-band frequency range and has a steering function to send the beam in a desired direction and lens characteristics that can reduce the beam divergence angle.

In particular, if this metasurface is flipped 180 degrees, it can be used as a receiver capable of rapidly separating and recovering OAM signals. Previously, OAM modes could only be distinguished by scanning the entire wide area of a concentric OAM beam, but this technology allows for mode differentiation within a short time simply by knowing the presence or absence of a signal entering the detector. The signal processing time becomes shorter.

Professor Lee Jong-won said, “This study presents the most realistic method to quickly identify metasurface-based OAM modes using a minimal number of detectors,” and expressed his expectation that “by adding OAM modes to metasurfaces, the channel capacity of 6G communication can be dramatically increased.”

Meanwhile, compared to the existing spiral phase plate (SPP) capable of generating OAM, the developed metasurface has the advantage of being thinner, allowing for weight reduction, and does not require a separate beam integrator, which can simplify the communication system.

The results of this study were published online on March 17 in Laser & Photonics Reviews, a world-renowned academic journal published by Wiley. The research was conducted with support from the Samsung Future Technology Development Program.