Researchers in the Zhang Lab at Boston University have unveiled a next-generation acoustic metamaterial—Phase Gradient Ultra-Open Metamaterial (PGUOM)—capable of suppressing broadband noise while preserving substantial airflow. Published in Scientific Reports, this development marks a leap beyond their 2019 “sound shield” that targeted narrowband noise using Fano resonance effects.
PGUOM incorporates phase-gradient metamaterial design: each supercell comprises three subwavelength unit cells—solid barriers in the outer two induce precise phase shifts, while a central open cell maintains up to 70% airflow. This arrangement converts incoming sound waves into spoof surface waves that dissipate along the structure, achieving broadband attenuation.
Unlike fixed-frequency solutions, PGUOM behaves like noise-canceling headphones for environments with fluctuating acoustic conditions, such as offices, factories, HVAC systems, or transportation hubs. Although there’s a slight reduction in peak attenuation compared to narrowband designs, the adaptability and real-world practicality are significantly enhanced.
Crucially, the researchers have already prototyped both rectangular and cylindrical forms via 3D printing, demonstrating scalability and geometric flexibility. Their approach supports customizable frequency targets and airflow, offering tailored sound control solutions across diverse applications.
For engineers and designers, PGUOM represents a breakthrough in harmonizing acoustic performance with ventilation needs, ushering in smarter, more adaptive noise suppression for dynamic real-world environments.