Computer Simulation of Magnetoelectric Antenna and Performance Comparison With Micro-Loop

Electromagnetic radiation can be produced using functional materials such as magnetoelectric (ME) composites, in which the magnetoelasticity and piezoelasticity of material are involved. The mechanical nature of the vibrations is used to miniaturize the ME antenna to micro-scale size. The antenna performance evaluation requires a multiphysics analysis of the structure. An ME antenna design and simulation is detailed using the finite element method (FEM) in COMSOL Multiphysics^® in which the structural mechanics, electrostatics, and magnetic field physics are coupled together to address the simulation needs. An antenna size of 250 $\mu \text{m}\,\,\times $ 50 $\mu \text{m}\,\,\times \,\,1\,\,\mu \text{m}$ is simulated within a static magnetic bias field of 20 mT. The nonlinear isotropic model is used for magnetostrictive material definition in which the prestress is defined by the magnetic bias. The model is linearized for radio frequency (RF) simulations to account for the AC simulation. The antenna farfield radiation pattern and the gain are computed using finite difference time domain (FDTD) by incorporating the extracted nearfield of the ME antenna in COMSOL. The simulated antenna impedance, radiation pattern and antenna gain are compared to an equivalent micro-loop magnetic antenna. In addition, electromagnetic computations are used to evaluate the coupling performance between the ME antenna and a larger loop antenna over a distance up to 20 mm in free space and biomedical tissues to address the potential of using ME antenna in medical implants for wireless communication and wireless power transfer.