Equivalent circuit model of magnetoelectric antenna in radial vibration mode

Abstract Magnetoelectric (ME) antennas utilize mechanical resonance instead of electromagnetic (EM) resonance to produce EM radiation, significantly reducing the antenna's size. This approach represents a highly promising strategy for antenna miniaturization. Currently, radial motion modes are present in piezoelectric resonators and piezoelectric antennas, but radial vibration modes in ME antennas remain largely unexplored. This paper is the first to investigate radially vibrating ME antennas from a circuit perspective. First, we derive the control equations governing radial motion through material constitutive relations and Newton's equations. Next, an equivalent circuit model is established using electromechanical analogy, and the radiation performance is characterized by defining the voltage gain. Multi-physics finite element simulations reveal that the resonance frequency of the inverse ME coefficient is 19.7 MHz, while the resonance frequency of the ME voltage gain is 18.7 MHz. The close agreement between these values verifies the accuracy of the proposed equivalent circuit model. Further simulations of the converse ME (CME) coefficient demonstrate that the CME coefficient in the radial vibration mode is two orders of magnitude higher than in the thickness vibration mode. Similarly, from the perspective of ME voltage gain, the radial vibration mode outperforms the thickness vibration mode by four orders of magnitude. This study highlights the effectiveness of equivalent circuit models in advancing ME antenna research and demonstrates the superior performance of radial vibration modes. It enhances the understanding of ME antenna vibration modes and provides a robust foundation for their design and optimization.