The Multifunctional Microwave Device Design And Equivalent Circuit Based On Double Layeredmagnetoelectric Structure

The converse magnetoelectric effect of the composite magnetoelectric materials is applied to ordinary microwave devices, which can not only realize a high quality factor and the adjustment range in GHz band with the external magnetic field, but also can realize the high precision and fast frequency band adjustment in MHz range with the external electric field. And compared with the traditional filter, it also has the advantages of low power consumption, low noise, and high quality factor. Therefore, it has great potential in the mobile communication system, electronic warfare system and other fields.In the design process of the device, improving the microstrip structure can improve the performance. And the T-shaped microstripstructure of band pass filter has the best effect. In addition, scholars have proved that it can widen the bandwidth with two blocks laminates. Nonetheless, the performance is unable to change once the device has been designed. The traditional method is making the device real after the electromagnetic simulation. But due to the introduction of magnetoelectric laminate, and considering the complex material parameters and boundary condition, this method can cause the simulation time consuming. In contrast, some scholars had put forward that using the method of equivalent circuit analysis can reduce the simulation time and improve efficiency with the less cost. Although the work on the equivalent circuit is going on, but the model is relatively single. So the reserch on devices with other structures has to be carried out.According to the above thinking, this paper has done the following research:Firstly, in the light of the magnetoelectric tunable microwave filters with the T-shaped microstrip line, the lumped equivalent circuit model is established. Based on the microwave transmission principle and ferromagnetic resonance mechanism, the equivalent circuit parameters of microwave filter are calculated.The effectiveness of the circuit is verified and the influence curves of magnetoelectric laminate in different size and magnetic fields on the performance of the filter and the equivalent circuit lumped parameters are predicted.Secondly, for the single band microwave device composed of a plurality of magnetoelectric laminates, the RLC series resonant circuit and ideal transformer model are introduced for characterizing the ferromagnetic resonance effect and the coupling effect between the microstrip line and magnetic structure. Finally, the generally lumped circuit model for magnetic and electric dual tunable devices with multi-block laminates is established, and the effectiveness is demonstrated. Then, the band characteristics and magnetic and electric field tunable properties are predicted by the lumped equivalent circuit. It can be obtained that using multi-block magnetoelectric structures not only can broaden the bandwidth of the filter, but also can adjust the work frequency band, which provides the theory basis for the design of devices.Finally, two spatial coupling structure of optional functions tunable magnetoelectric microwave filters are designed with double magnetoelectric laminates, based on the microwave magnetoelectric effect and ferromagnetic resonance effect, combining with the resistance performance of the single band filter and the bandpass performance of the coupling band, which can not only inherit the advantages of magnetoelectric microwave device with adjustable working frequency and overcome the existing defect that the properties of magnetoelectric tunable filter are single, but also can improve the device flexibility and multifunction availability and is more suitable for the application of the relevant frequency tunability in wireless communication. It has great creativeness and great application prospect in China mobile, satellite communications and other fields.