Researchers 3D print compact, low-cost vortex beam generators

“Applications such as 5G/6G wireless networks have growing demands for high-capacity, anti-interference communication systems, requiring innovative solutions,” said Li Jianxing, leader of the research team at Xi’an Jiaotong University in China. “Although OAM-carrying vortex beams can potentially improve spectral efficiency and communication capacity, current methods of generating these beams suffer from inefficiencies, high manufacturing costs, and vulnerability to unwanted frequency band interference.”

In Optica Publishing Group Journals Optics ExpressIn the article, the researchers describe how they used 3D printing to create an OAM beam generator that could be used as a complex antenna system for advanced wireless communications. This device generates a high-capacity vortex beam and features integrated gain filtering to amplify the desired signal while blocking interference to ensure clear, efficient transmission.

“Our OAM beam generator is particularly suitable for 5G/6G wireless communications as well as remote sensing and imaging,” said Yuanxi Cao, the corresponding author of the paper. “For example, integrating this device into communications towers could improve streaming and online connectivity at large gatherings such as music festivals or sporting events, where high user density often overwhelms existing networks, resulting in slow speeds and The connection is interrupted.

Integrated signal filtering

The new 3D printing OAM beam generator uses an integrated gain filter power divider to evenly divide the signal while filtering out unwanted frequencies at the source. This minimizes disruption and reduces the need for additional external components. The researchers also used an air-filled all-metal structure to avoid dielectric losses, ensuring higher radiation efficiency and greater power handling capabilities.

The device works by first splitting the incoming signal into eight equal parts using a built-in power divider, filtering out unwanted frequencies along the way. Each signal is then phased through a special path to achieve the precise alignment needed to create the vortex beam. Finally, the signal is transmitted through a circular antenna array, producing a vortex beam with the desired characteristics.

Manufacturing and testing

After performing advanced simulations to fine-tune the filtered power divider for precise in-band signal transmission and effective out-of-band rejection, the researchers used selective laser melting to 3D print a prototype device using high-precision and aluminum alloy known for its high reliability.

“We used selective laser melting 3D printing technology to manufacture the device as a monolithic structure,” Cao said. “This eliminates the need for assembly, reduces manufacturing costs and ensures precise alignment of components – all of which are critical for high-frequency applications.”

Experimental testing confirmed that the prototype element achieved the required beam characteristics with a mode purity of approximately 80%. It also features high out-of-band rejection of over 30 dB, significantly reducing interference and ensuring clean signal transmission.

Researchers are currently working to enhance the performance of OEM beam generators by improving gain, efficiency and signal filtering. They also hope to expand potential applications by exploring multi-mode OAM generation and testing it over a wider frequency range, such as terahertz communications. The researchers noted that commercialization of the device will require improved 3D printing to achieve scalability, integrate it with existing systems, ensure compliance with regulations, and verify performance in real-world applications such as 5G and satellite communications.