Integrated Design And Optimization Of Material,Structure And Performance Of Magnetoelectric Antenna Based On Bulk Acoustic Resonance

The traditional antenna miniaturization design faces three principle problems: difficulty in size reduction(greater than ? /10,difficulty in impedance matching(mirror current reflection,and low radiation efficiency(current ohmic loss,.The root of these problems lies in the working mechanism of traditional miniaturized antennas based on electromagnetic resonance and the performance of antennas is still limited by Chu-Harrington limit.The introduction of the concept of magnetoelectric antenna provides a new solution for antenna miniaturization design.The magnetoelectric antenna is composed of piezoelectric material and magnetostrictive material.The magnetic material can induce the magnetic field component of the electromagnetic wave and convert it into an acoustic wave which is output in the form of voltage;In turn the piezoelectric material is strained by the voltage and the strain is transmitted to the magnetic material and excites it to oscillate magnetization radiating electromagnetic waves.There are two types of excitation acoustic waves for magnetoelectric antennas: surface acoustic wave and bulk acoustic wave.This paper aims to study the integrated design of the material structure and performance of the bulk acoustic wave magnetoelectric antenna in detail and to carry out simulation analysis and verification of the proposed design scheme and further optimize the antenna performance.The content is as follows:1.The integrated design scheme of material structure and performance of BAW resonant magnetoelectric antenna is proposed.First select the appropriate material according to the material characteristics.Then considering the antenna material radiation performance magnetoelectric coupling strength antenna mechanical strength and processing accuracy starting from the one-dimensional analytical model of the magnetoelectric antenna the antenna is designed as a two-layer 2-2 type magnetoelectric structure based on bulk acoustic wave resonance.Finally the Mason equivalent circuit model of the magnetoelectric antenna is established and the geometric size of the antenna is determined according to the design frequency and impedance matching.2.Establish a finite element model of the magnetoelectric antenna and the design scheme of the antenna is analyzed and verified by simulation.Firstly the resonance characteristics of the magnetoelectric antenna are analyzed and the influence of various structural parameters of the antenna on its acoustic resonance performance is studied.The convex frame electrode structure and the irregular quadrilateral electrode shape are designed to suppress the parasitic resonance of the antenna.Then the magnetoelectric coupling when the magnetoelectric antenna receives electromagnetic waves is simulated and analyzed.The simulation results show that the output voltage of the antenna is the largest near the resonant frequency and the output voltage increases with the increase of the bias magnetic field.Finally the electromagnetic characteristics of the magnetoelectric antenna are simulated and analyzed and the obtained antenna radiation pattern is similar to that of a dipole antenna.3.Two multi-band design methods for magnetoelectric antennas are proposed.The first method utilizes the multi-modal acoustic resonance of the magnetoelectric antenna to optimize the design of the width and thickness of the magnetoelectric antenna so that the rectangular magnetoelectric antenna can work in any two different frequency bands;In the second method by integrating a plurality of parallel arrays of magnetoelectric antenna units working at different frequencies the magnetoelectric antenna array can work in any different frequency bands.4.A mechanism for widening the bandwidth of magnetoelectric antennas is proposed By connecting three magnetoelectric antenna units with a frequency difference of 0.6 MHz operating near the series resonant frequency in parallel the bandwidth of the overall antenna array is more than four times higher than that of a single antenna and as the number of parallel array units increases the antenna bandwidth Continuous improving.Similarly for a magnetoelectric antenna operating near the parallel resonance frequency a plurality of antenna elements with a certain frequency difference are connected in series to superimpose the parallel resonance peaks of the antenna thereby increasing the bandwidth of the antenna.Then the simulation analysis shows that the bandwidth of the antenna is positively correlated with its electromechanical coupling coefficient.Finally a magnetoelectric antenna structure with large electromechanical coupling coefficient is proposed and the effects of various parameters on the electromechanical coupling coefficient of the antenna are simulated and analyzed.