Influence of Permeability Dispersion on Radiation of BAW Antenna: Modeling of Multiphysics Dynamic Coupling

Coupling of multiphysics including electrodynamics, elastodynamics, magnetodynamics, and electromagnetic (EM) radiation is involved in the operating process of bulk acoustic wave (BAW) antenna. There is still no good way to design the structure and evaluate the performance of the antenna in theory. Therefore, the multiphysics dynamic coupling model of the antenna is constructed by uniting Newton’s equation for acoustic wave, Maxwell’s equation for EM wave, and Landau–Lifshitz–Gilbert (LLG) equation for spin wave with constitutive relations of multiferroic materials to discuss the dispersion law of permeability and magnetomechanical coupling factor for the magnetostrictive layer. The importance of consistency between ferromagnetic resonance (FMR) frequency and BAW resonant frequency is demonstrated. The analysis shows that both increasing the anisotropic field or the saturation magnetization and decreasing the FMR linewidth are beneficial to improving the internal energy conversion efficiency and the average radiated power for BAW antenna. In addition, a micromagnetic module is introduced into finite element analysis (FEA) software to simulate the precession of unit magnetic moment at different frequencies. Thus, the analytical model is verified from the perspective of power absorption.