A rapid surge in the research on very low frequency (VLF) antennas is occurring due to the demand for radio navigation and special environment communications such as underwater and underground applications. Among them, magnetoelectric (ME) antennas have recently proven to be a prospective solution for miniaturization of VLF communication systems. However, the essential magnetic bias fields (Hdc) lead to challenges of miniaturization, electromagnetic interference, and noise sources for ME antenna application. Here, a bias-free VLF ME antenna based on the magneto-gradient ME composite (i.e., annealed Metglas/Metglas/PZT/Metglas/annealed Metglas) has been designed. Owing to the interaction effect between multi-unannealed/annealed Metglas, the magneto-gradient ME composite exhibits a large direct and converse ME response (αDME = 107 V/cm Oe and αCME = 9 Gs/V at resonance) at bias-free, which is about 63% and 33% of the maximum value under optimal magnetic bias for unannealed ME composites. Moreover, a digital amplitude shift keying (ASK) modulation method is proved suitable for the as-made bias-free VLF ME antenna. Such a bias-free ME antenna provides a practicable strategy for miniaturization of VLF communication.

The magnetoelectric (ME) antenna with acoustic driven has become a new scheme for solving remote wireless communication from ULF to VLF bands due to its small size and anti-interference solid capabilities. The paper presents a model based on electrostriction, magnetostriction, and Maxwell equations. The capability at the resonant frequency ( f_r ) of electric field ( E ) and magnetic flux density ( B ) radiation in space are examined through variations in voltage ( V ), magnetic field ( H ), and structure. This model relates the V to the spatial B distribution and lays a foundation for the ME antenna’s structural design and characteristic research. The actual test shows the asymmetric ME antenna has excellent electromagnetic (EM) radiation ability in the SLF band. The magnetic flux intensity can reach 2.2 nT at 1 m. By constructing ME antenna arrays, radiation intensity can also be superimposed. The value of magnetic flux density reaches 7.2nT@1m at 110 Hz and 3.8nT@1m at quasi-static frequency. This study demonstrates that asymmetric ME antenna arrays can be used for narrowband communication in the SLF and broadband long-distance communication.

Long-wave antennas are extensively used in special environment communications, such as underwater and underground applications, but the huge size of traditional electrical antennas restricts their applications. The emergent acoustically excited magnetoelectric (ME) antennas is expected to solve the portability problem. However, the contradiction between the radiation intensity and modulation rate (i.e., baud rate) of ME antenna remains an obstacle to its development. Here, we propose a very low frequency (VLF, 3–30 kHz) ME antenna based on a Rosen-type magnetostrictive-piezoelectric ME composite, which collaboratively optimizes both radiation intensity and transmission rate. The radiation intensity and efficiency of the proposed ME antenna were, respectively, two and three orders of magnitude higher than those of a same-sized loop antenna. A VLF communication system based on the Rosen-type ME antenna utilized amplitude shift keying (ASK) modulation was demonstrated. The system achieved an ultra-high baud rate of up to 2 kbaud (i.e., 2 kbps bit rate), confirming the feasibility of this approach.

With the popularity of electric vehicles, the ever-increasing demand for high-capacity batteries highlights the need for monitoring the health status of batteries. In this article, we proposed a magnetic imaging technique (MIT) to investigate the health status of power batteries nondestructively. This technique is based on a magnetic sensor array, which consists of a 16-channel high-performance magnetoelectric sensor, and the noise equivalent magnetic induction (NEB) of each channel reaches 3–5 pT/Hz^1/2@10 Hz. The distribution of the magnetic field is imaged by scanning the magnetic field variation of different positions on the surface. Therefore, the areas of magnetic anomalies are identified by distinguishing different magnetic field abnormal results. and it may be possible to classify the battery failure, so as to put forward suggestions on the use of the battery. This magnetic imaging method expands the application field of this high-performance magnetoelectric sensor and contributes to the battery’s safety monitoring. Meanwhile, it may also act as an important role in other nondestructive testing fields.

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.

The mechanical ME antenna is a device that generates near-field radiation by acoustic actuation and has the potential to achieve air to sea and air to soil cross-media communication. In this work, we established a nonlinear coupling model based on hysteresis electrostriction, magnetostriction, and Maxwell equations. The nonlinear and hysteretic behaviors of ME antennas with electric field, frequency, and polarization intensity are discussed. The near-field radiation behavior in this model accords with the characteristics of a magnetic dipole, which can provide a reference for the nonlinear research and parameter design of ME antennas. In the actual test, the optimal volume ratio of the ME antenna is found to improve the unit performance. The ME antenna based on different piezoelectric materials shows that the nonlinear behavior of the ME antenna is closely related to the ferroelectric properties. Experiments show that the ME antenna based on PMN-PT single crystal has excellent near-field radiation performance, which can reach 25nT at 1m.