Enhancing VLF communication via performance-optimized magnetoelectric antenna arrays

Abstract

Magnetoelectric (ME) antennas typically exhibit high-quality (Q) resonance, which fundamentally limits their bandwidth. This constraint hinders their effectiveness in very-low-frequency (VLF) communication and related applications. This work presents a miniaturized serial ME antenna array, leveraging the strain-mediated magnetostrictive–piezoelectric coupling mechanism. By clamping and integrating three ME antenna units with slight fabrication-induced frequency dispersion, serial coupling is achieved, resulting in partially overlapped frequency responses and a broadened effective bandwidth at the array level. The physical behavior of both single and array antennas is systematically analyzed using a circuit voltage noise model and a modified Butterworth–Van Dyke equivalent circuit, providing quantitative insight into resonance, noise, and bandwidth enhancement mechanisms, which are validated by experimental measurements. The array shows a 2.78-fold increase in output voltage amplitude, a 1.4-fold improvement in bandwidth, and achieves a limit of detection of 165 fT, with a compact volume of 4.5 cm3. Amplitude-shift keying-based digital modulation experiments further demonstrate that, without DC magnetic bias, the array can reliably receive VLF binary signals at a 1 m distance with a signal-to-noise ratio of 15.61 dB. These results confirm the underlying physical mechanisms and engineering feasibility of the array approach in enhancing ME antenna bandwidth, sensitivity, and anti-interference capability. This strategy provides a novel and scalable approach for picoTesla-level VLF communication and biomagnetic sensing, with significant implications for applied physics.