Magnetoelectric (ME) antenna operates at the acoustic wave resonance rather than EM wave resonance, thus it shows significant superiority for developing compact antennas and antenna arrays. The simulation of ME antenna involves the nonlinear coupling of Electrostatics, Solid Mechanics, and Magnetic physics, making it difficult to model such devices. This paper proposes a fully multi-field coupled model for the ME antenna, in which the nonlinear magnetostrictive model is taken into account. The nonlinear magnetization is solved and then AC and DC simulations are performed by coupling different physics. The effects of magnetic bias and pre-stress on the converse magnetoelectric (CME) coupling and near-field radiation are discussed for the first time, to regulate the performance of the ME antenna with fixed dimensions. The results indicate that the magnetic bias and pre-stress can change the resonance frequency, CME coefficient, and near-field radiation of ME antenna. Particularly, it should be noted that pre-stress has the opposite effect in the low and high regions of the bias field. The near-field radiation is significantly enhanced by applying a proper magnetic bias or pre-stress. This simulation may facilitate the understanding of nonlinear CME behavior and provide a basis for designing nonlinear active and tunable ME antenna.

Magnetoelectric (ME) effect in a Ni/PZT/Terfenol-D composite cantilever was tested under three different magnetic loading modes. The frequency-dependent ME effect and dual-peak phenomenon were observed in the experiment. The influence of orientations of magnetic fields on the dual-peak phenomenon of ME coupling was investigated. Magnetic field distribution inside the ME composite structure was simulated, which agrees well with experimental data. The experiment results indicate that ME coefficient versus bias magnetic field curve presents a novel dual-peak phenomenon near the resonant frequency, and the ME coefficient which depends upon the amplitude and orientation of magnetic field presents a nonlinear shift whether at the resonant frequency or not. In addition, the optimal angle corresponding to the largest ME coefficient for different bias fields were obtained. The proposed ME composites-based sensors can be used for detecting or harvesting magnetic signals of uncertain orientations and amplitudes in complex environments.

This paper proposes analytical solutions for the resonant radiation performance of bending-mode magnetoelectric (ME) antennas. The strain-mediated Converse ME (CME) coupling model of bending-mode ME antennas is first established by solving nonlinear constitutive equations and bending governing equations using the elastic mechanics method. Then, the calculated magnetic flux and electric displacement are employed to propose a resonant radiation field model based on the dipole method. The numerical results for the CME coefficient show a good agreement with the experimental data. It can be observed that the volume fraction ratio of the piezoelectric layer can control the CME coefficient and radiation efficiency with the same variation trend since it can determine the bending strain via changing the location of the neutral layer of the ME antennas, which also demonstrates the strain-mediated essence of the ME antennas. In addition, the volume fraction ratio can tune the resonant frequency within a wide range. The gain of the ME antenna is stable and higher than −168 dB with the volume fraction ratio ranging from 0.2 to 0.7. The tensile stress and compressive stress have the opposite effect on the resonant frequency at low and high bias magnetic fields. Meanwhile, the tensile (compressive) stress is beneficial for both the radiation and gain in the low (high) bias field region. This model may facilitate the understanding of the bending-mode radiation mechanism of ME antennas and provide a basis for designing asymmetric ME antennas.

A magneto-elastic-optical coupling model for Terfenol-D based single-mode optical fibers is proposed, in which the nonlinear magneto-elastic coupling characteristics of Terfenol-D is taken into consideration. The field-dependent material constants for magnetic coating is predicted and in good agreement with experimental results. The coupling effects of external stimuli (e.g. magnetic field and stress) on magneto-optic (MO) coupling coefficient of optical fibers are investigated for the first time. The results show that the relative phase change is enhanced by changing the thickness or Poisson's ratio of constituent materials. More importantly, appropriate applied tensile/compressive stress can control the value of optimal bias field as well as enhance MO coupling coefficient of optical fibers under different magnetic fields. This research provides a method to evaluate and improve magnetic performance of the optical fiber magnetic field sensors consisting of giant magnetostrictive materials.