A journal paper in collaboration with the University of Bologna and Fraunhofer IKTS (Dresden) has been accepted for publication in Advanced Intelligent Systems.

Abstract:

Elastic wave control underpins numerous technologies, from structural health monitoring and biomedical imaging to wireless communications and energy harvesting. Conventional phased arrays enable dynamic beamforming but are bulky, power-intensive, and complex, limiting their integration into compact or distributed systems. Here, we present a meta-transducer design that embeds wavenumber-domain filtering directly into the electrode geometry, enabling frequency-controlled unidirectional generation of ultrasonic guided waves without active phasing networks. A key innovation is the use of error-diffused spatial dithering to approximate continuous 2D filters with binary patterns by shaping the transducer electrodes, suppressing sidelobes and enhancing angular resolution. Finite element simulations and experimental validation with a scanning laser Doppler vibrometer confirm that the Frequency-Steerable Acoustic Transducer (FSAT) achieves sharp, frequency-tunable beam steering across a 180° sector with over 80% reduction in sidelobe energy compared to conventional designs. This approach enables ultra-compact, energy-efficient ultrasonic devices with wavefront control, offering a pathway to advanced applications in guided wave imaging, IoT-enabled sensing networks, and ultrasonic communications.

Reference:

Mohammadgholiha, M. ; Moll, J. ; Tschöke, K. ; Kruska, C. ; Gebhardt, S. E. and De Marchi, L., Ultrasonic Rainbow: A Meta-Transducer for Frequency-selective Elastic Wave Control via Dithering-based Wavenumber Tuning, Advanced Intelligent Systems, 2026 (accepted in May 2026)