Frequency-selective acoustic sensing using circular PVDF-based artificial basilar membranes

Understanding and replicating the natural frequency selectivity of the cochlea is critical for advancing hearing devices and biomimetic acoustic sensors. This study presents a circular artificial basilar membrane (CABM) as a piezoelectric acoustic sensor inspired by the tonotopic frequency selectivity of the basilar membrane in the cochlea. The sensor integrates four distinct PVDF thin films into a single robust platform, enabling simultaneous multi-frequency detection. The sensor operates across a biologically relevant frequency range of 100–3000 Hz, covering essential human speech and environmental sound frequencies. A major challenge in biomimetic acoustic sensing is achieving frequency selectivity while maintaining a conformal and scalable design. This study addresses this by optimizing membrane geometry, device design, and experimental configurations. Additionally, minimizing wave reflection, diffraction, and entrapment effects required systematic optimization of sensor positioning and testing conditions. This research integrates analytical modeling, numerical simulations, and experimental validation to investigate membrane dynamics. Resonance frequencies were derived using acoustic principles, refined through Finite Element Method (FEM) simulations, and validated via Laser Doppler Vibrometry (LDV). The effects of membrane diameter, sound intensity, source distance, and sound direction were analyzed to characterize sensor behavior. The successful integration of the four-channel CABM system, mimicking the cochlea's tonotopic behavior, marks a step forward in artificial cochlear devices. This work demonstrates a scalable and compact solution for multi-frequency acoustic sensing, with potential applications in cochlear implants, speech recognition, and bio-inspired auditory systems.