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Yisi Liu MS Thesis Defense
December 7, 2023 @ 2:00 pm - 3:00 pm
Title: Experimental research on the Nonlinear Magnetoelectric Effect of the VLF ME Antennas
Committee Members:
Prof. Nian Sun (Advisor)
Prof. Yongmin Liu
Prof. Xufeng Zhang
Abstract:
Magnetoelectric (ME) coupling effects in ferromagnetic and piezoelectric composites involve the control of electric polarization (P) by applying a magnetic field (H) (direct ME effect), or the manipulation of magnetization (M) through an electric field (E) (converse ME effect) . These effects are facilitated by the mechanical deformation in the ferroic phases resulting from the combination of magnetostriction and piezoelectricity. In single-phase materials, the breakthrough in achieving large ME coefficients has further advanced the development of ME materials and devices. Consequently, numerous multifunctional ME devices, such as mechanical antennas, magnetic sensors, tunable inductors, and filters, have been developed. This thesis has provides a summary and categorization of these devices based on their physical mechanism and type of ME effects. The inclusion of mechanical ME antennas based on piezoelectric/magnetostrictive heterostructures with acoustic actuation reflects the significant interest in this topic. Notably, a maximum communication distance of 120 m for a very low frequency (VLF) communication system has been achieved using a pair of mechanical ME antennas. Subsequently, we will focus on introducing and reviewing the materials and devices related to the ME effect, as well as the application of ME mechanical antennas in very low frequency (VLF) communication systems.
In addition to that, we developed a transmitter with a Metglas/PZT/Metglas structure antenna. Our study focuses on investigating the transmission effects of this antenna when employing direct antenna modulation techniques to enhance data transmission. Through our research, we have introduced a novel modulation method by modulating the antenna. We observed that this modulation method produces a more stable and stronger signal.