External field dependence of electrical and radiation properties of multiferroic antennas

Abstract

Multiferroic antenna (MA) is a novel type of antenna which generates and transmits electromagnetic waves based on acoustic resonance. However, the theoretical electrical and radiation properties of MA are different from those in practical work because the influence of external fields (magnetic bias, pre-stress, and temperature field) on magnetoelectric coupling has not been considered enough. This paper proposed a nonlinear equivalent circuit model to quantify the external field dependence of performances of MA. The nonlinearity of material parameters is introduced in the form of variable acoustic impedances to research the regulation of external fields on the multi-physics coupling of MA. The proposed model is verified by full wave electromagnetic simulation to ensure the reliability of using the equivalent circuit to analyze the case of MA (AlN as a ferroelectric phase and Terfenol-D as a ferromagnetic phase). The results show that external field parameters can not only change the resonant frequency but also change the electrical and radiation properties. The higher voltage gain and better impedance characteristic can be obtained by tuning the external fields. In this case, the electrical and radiation properties of MA are, respectively, increased by 471%, 1100%, and 233% under different magnetic bias, pre-stress, and temperature. This work provides an effective method for predicting the evolution of MA performances under external fields, a more comprehensive idea for performance enhancement of MA.