High conductive environments such as deep earth and seawater bring challenges to existing electronic communication technology. Very Low Frequency (VLF) communication technology is supposed to be a feasible solution for conductive environments communication due to its improved radiation attenuation. Herein, we report a VLF 2 Frequency Shift Keying (2FSK) signal receiving antenna based on Metglas/0.7Pb(Mg _1/3 Nb _2/3 )O ₃ –0.3PbTiO ₃ (PMN-PT) magnetoelectric (ME) cantilever. The cantilever beam is predicted by finite element simulation and shows double electromechanical resonance (EMR) peaks. Experimental results reveal that the ME cantilever demonstrate strong resonant ME coupling coefficients as high as α _Q ⁓ 100 nC/Oe at 6 kHz and 18 kHz, which ensures the high responsivity and low bit error rate during modulation in FSK communication application. The noise equivalent magnetic field of the whole antenna system at the resonant peak is measured to be as low as 12.56 fT/Hz ^1/2 (at 18.44 kHz), implying a huge signal to noise ratio (SNR) advantage. On the basis of the above preparation, the ability of ME antenna to receive 2FSK signal is verified. ME antenna shows good performance on demonstrate FSK signals reception which is 200 bit/s. Such an ME composite based mechanical antenna shows great potential in the conductive environmental communication application.

In this work, a tachometer based on a Metglas/PZT/Metglas magnetoelectric (ME) composite was developed to achieve high-precision rotational speed measurement over a wide temperature range (−70 °C to 160 °C). The tachometer converts external magnetic signals into electrical signals through the ME effect and operates stably in extreme temperature environments. COMSOL Multiphysics software was used for simulation analysis to investigate the ME response characteristics of the composite in such environments. To evaluate the properties of the ME composite under different conditions, its response characteristics at various frequencies, DC bias, and temperatures were systematically investigated. A permanent magnet and a DC motor were used to simulate gear rotation, and the voltage output was analyzed by adjusting the position between the sensor and the DC motor. The results show that the measured values of the ME tachometer closely match the set values, and the tachometer demonstrates high measurement accuracy within the range of 480 to 1260 revolutions per minute (rpm). Additionally, the properties of the ME composite at different temperatures were examined. In the temperature range from −70 °C to 160 °C, the ME coefficients exhibit good regularity and stability, with the measured trend closely matching the simulation results, ensuring the reliability and accuracy of the ME tachometer. To verify its practicality, the measurement capability of the ME tachometer was comprehensively tested under extreme temperature conditions. The results show that in high-temperature environments, the tachometer can accurately measure speed while maintaining a high signal-to-noise ratio (SNR), demonstrating excellent anti-interference ability. The proposed ME tachometer shows promising application potential in extreme temperature conditions, particularly in complex industrial environments that require high reliability and precision.

Wireless power transfer systems offer significant benefits for real-time gastrointestinal (GI) monitoring due to their durability and non-invasiveness. Here, we present a fully integrated GI monitoring capsule enabled by a high-performance magnetoelectric (ME) composite (Metglas/PMN-PT/Metglas) for wireless energy delivery and real-time physiological sensing. Operating at resonance frequency, the ME composite achieves an excellent ME coefficient of 392 V/(cm · Oe) and provides a high power density of 12.72 mW/cm3 in a compact volume. The system wirelessly powers a dual-function temperature–pressure sensor and transmits data, maintaining stable operation for over 12 h under simulated GI conditions. This work demonstrates ME-based energy transfer in ingestible devices, integrating efficient non-contact energy harvesting with a compact form. The proposed approach enables battery-free and long-term GI diagnostics.