Multiphysical Field Driven Low-Frequency Magnetoelectric Antenna Array With Nonlinearly Enhanced Magnetic Field Transmission

Recently, acoustically driven magnetoelectric (ME) antennas provide a promising candidate for portable low frequencies (LFs 30-300 kHz) transceivers in the high-loss medium. A single ME antenna, hence, constrains the transmitted magnetic field due to the weak magnetic moment and low strain-modulated magnetization efficiency. A multiphysical field driven ME antenna array consisting of double elastic plates sandwiched between multiple arranged PZT8/Metglas/Ni laminates is, hence, proposed, which can enhance the transmitted magnetic field nonlinearly with increased antennas. Here, the accumulated ac strain and magnetic field of multiple antennas intensify with increased antennas and couple in a positive feedback way. Specifically, the ac piezostrain of adjacent antennas couples through the elastic plate along the length direction, enhancing the modulation of neighboring antennas' magnetization oscillations; meanwhile, the enhanced magnetic coupling among adjacent antennas along the width direction produces additional magnetostrictive strains, which enhance the Q values of converse ME (CME) effect and effective strains propagated in the elastic plate, thereby further improving the transmitted magnetic field. First, an equivalent circuit model based on magnetic and strain-modulated motion equations is proposed to understand and optimize the ME antenna array. Furthermore, due to the multiphysical field driven effect of the fabricated antenna array, the $3 \times 3$ array can enhance the transmitted magnetic field to 19.8 times compared to that of a single antenna. Such nonlinear improvements can further reach 1337 times for the $10 \times 10$ antenna array. This provides a power-efficient method to enhance the magnetic field transmission efficiency at LF.