The Magnetoelectric Device Equivalent Circuit Research And Microwave Device Design Based On The Magnetoelectric Effect

Multiferroic magnetoelectric (ME) materials have shown enormousapplication value in the low frequency and microwave fields, because of its efficientmagnetoelectric conversion performance (which is the appearance of an electricpolarization upon applying a magnetic field or a magnetization upon applying anelectric field). In the low frequency fields, multiferroic ME materials show as theform of transducer and sensors.etc. they realized the conversion between electricfield and magnetic field, having an important position in the weak magnetic fieldmeasurement. Now, the main researchs in the international field are focus on thepreparation of the ME device, strengthen the ME effect through the magnetoelectricmaterial matching.etc. The corresponding theory research (such as Green’s functiontechnique and Equivalent circuit method.etc) realized the evaluation of the devicequalitatively and quantitatively, but still have need to improve; In the microwavefields, using the ME effect (ferromagnetic resonance effect) of the multiferroic MEmaterials, realized the large magnetic tuning and small electric tuning. So they werewidely used in the microwave devices, such as microwave resonator, filter, phaseshifters and delay lines.etc. Now, the main researchs in the international field arefocus on the experiment test of new devices, equivalent electric tuning.etc. theresearch on the lumped equivalent circuit of ME microwave devices hasn’t begun.At the same time, there are still have the following questions should bediscussed: How to realize the accurately analysis and theoretical predicts on theresonant magnetoelectric characteristics and bias magnetic field sensingcharacteristic of the magnetoelectric laminate composites, in order to reduce theexperiment cost; Presents a new analysis method, which will realize the fastsimulation and prediction of the performance of the ME microwave devices, in orderto reduce the experiment cost; how to realize the fast analysis and geometric sizeoptimization design of the ME microwave devices; how to realize themulti-functionly and multi-formly of the ME microwave devicesAccording to the above problems, this paper will work in the following:Firstly, in the low frequency fields, we used the equivalent circuit method, and researched on the ME characteristic of the magnetoelectric laminate composites.Including: Presented the novel explicit nonlinear expressions for analyzing theresonant ME coefficient and bias magnetic field sensing of the magnetoelectriclaminate composites. Compared with the experimental results, they all showed goodagreement both qualitatively and quantitatively. Then, we predicted themagnetoelectric conversion characteristics and bias magnetic field sensingcharacteristic of the magnetoelectric laminate composites.Secondly, in the microwave fields, this paper first proposed a fast simulationand analysis method for the ME microwave devices which using the lumpedequivalent circuit of the devices. We presented two novel lumped equivalent circuitmodelings of the ME microwave devices. Including: presented the novel lumpedequivalent circuit modeling of the magnetoelectric tunable microwave bandstop filterand magnetoelectric tunable microwave resonator respectively. Proved the validityof these two modelings, and then analyzed their phenomenon of FMR resonantfrequency shift by tuning the electric field.Based on the third chapter in this paper, we used the lumped equivalent circuitmodelings and FMR effect at first. Completed the fast analysis and geometric sizeoptimization design of the ME microwave devices. Including: study the influence ofthe external electric field and ME laminate composites geometric size on themagnetoelectric tunable microwave bandstop filter; study the influence of theexternal electric field and microstrip/substrate geometric size on the magnetoelectrictunable microwave resonator.Based on the fourth chapter, we used the stepped impedance lowpass filter andME laminate composites, followed the FMR, we designned a practical ME tunabledual-passband microwave filter in the TD-SCDMA band. This filter could pass theA and B band of TD-SCDMA, and isolated the band of WCDMA andCDMA2000RX, then we discussesed the performance of the dual-passband filter.Compared with the existing filter, this filter is multi-functionly and novel.