The Multi-ifeld Coupling Mechanism Of Multiferroic Mateiral And Application In Microwave Filter

The multiferroic materials are the materials with two or more basicproperties of iron. These materials have broad application in the modern electronicdevices with the development of miniaturization and multi-function. And theME(magnetoelectric) composites have great application value in ME sensors andtunable microwave devices because of the strong ME properties. The research of theME multiferroic materials multi-field coupling theory can provide more theoreticalbasis for designing the devices which contain ME composites.Firstly, we create a numerical model of magnetic-mechanical-electric couplingeffect based on the nonlinear magnetostrictive constitutive. Compared with theexperimental results, the ME field coefficients change with bias magnetic fieldpredicted by our model shows a good agreement with the experimental result eitherqualitatively or quantitatively. On this basis, this paper predicts the ME conversioncoefficient of ME laminated composites, and analyzes the influences of the thicknessratio of magnetostrictive layer, saturation magnetization, the geometry of laminatedcomposites, and the types of piezoelectric materials. We believe that this researchprovide a theoretical basis for the preparation of magnetoelectric devices with goodmagnetoelectric conversion characteristics.In order to study the ME tunable mechanism of microstrip with ME laminated compositesas substrate. We deduce the microstrip’s effective permeability and Characteristic impedanceformulas when the ferrite substrate is demagnetized, latched, and fully magnetized. Comparedwith the experimental results and the simulated results, the effective permeability changewith the frequency of microwave predicted by our formulas is good agree with theexperimental results and the simulated results. And it explains the magnetic tunablemechanism of ferrite microstrip resonator. Finally, by using the ME coefficients, wetest the microstrip resonator with substrate of the ferrite/piezoelectric laminatedcomposite, the results proved the feasibility of the equivalent electric tuning. In myopinion, the theory research of ME tunable mechanism can procide some guidancefor designing the microstrip devices contain the ME laminated composites substrate. On this basis, we designed a ME dual-tunable band pass microwave filterapplied in5GHz. It can be used in WLAN transceiver system based on502.11astandard. The filter can realize the function of magnetoelectric dual-tuning, with thesubstrate of magnetoelectric laminated composites. With the characteristics of smallsize, high efficiency, low energy consumption and low noise, the filter has goodprospects in microwave communication.