Acoustically Mediated Piezoelectric Antenna for Ultra-compact Biomedical Electronics

Designing ultra-compact antennas for implantable bioelectronics is challenging because antennas typically require a size comparable to the electromagnetic (EM) wavelength for high performance. This study presents an acoustically mediated piezoelectric (AMP) antenna that leverages the direct coupling of the mechanical resonance with the quasi-static electric field component at the first time. Our experiments demonstrate a 12 dB enhancement in antenna reception near the mechanical anti-resonance frequency, with the antenna size reduced to 1/300th of the EM wavelength. The power transfer efficiency (PTE) of AMP antenna shows a strong correlation with the quality factor and impedance value at the anti-resonance frequency, which can further be effectively enhanced through antenna arraying. In a 25-element array, we achieve a PTE of 0.0539% at 50mm, with a figure of merit (FoM) for wireless power transfer (WPT) surpassing existing technologies around 400 MHz. This work underscores the potential of the AMP antenna for applications in implanted bioelectronics.