Research On Microwave Ferrite Material Ferromagnetic Resonance Linewidth Detection Device

Microwave ferrite materials are widely used in civil and military fields such as communication,television,radar,artificial satellite,missile system,electronic countermeasure system,high-energy particle accelerator and so on.In order to adapt to the development of 5G communication technology,microwave ferrite materials need to have smaller ferromagnetic resonance linewidth.Therefore,accurate measurement of ferromagnetic resonance linewidth has become an important work in the research and development of microwave ferrite and the design of 5G electronic devices.Based on the resonant cavity method,a set of high-precision microwave ferrite ferromagnetic resonance linewidth measurement system is developed in this paper.The generation mechanism of ferromagnetic resonance phenomenon and the measurement principle of ferromagnetic resonance linewidth are analyzed.The theoretical basis of resonant cavity method is analyzed.The simulation measurement of ferromagnetic resonance linewidth is carried out based on HFSS software.The influence of sample size on the measurement results is studied in HFSS software,and the sample diameter suitable for measurement is obtained.As for the problem that it is difficult to explore the scale of the sample meeting the perturbation theory,a method to judge whether the sample meets the perturbation theory through the resonance curve is proposed.Based on the measurement requirements of the system,this paper analyzes and deduces the electromagnetic field distribution in the rectangular resonator and the relationship between the size,resonant frequency and oscillation mode of the resonator,and designs the rectangular resonator in TE₁₀₆mode.Crystal detector and oscilloscope are used to characterize the change of signal power,which improves the cost performance of the system;High resolution variable attenuator,programmable power supply and Gauss meter are used to improve the measurement accuracy of the system.According to the measurement range of the system,this paper selects three samples with different ferromagnetic resonance linewidth to test,and comprehensively verifies the measurement accuracy of the system.For narrow linewidth samples,the measurement error shall not be greater than 1Oe;For large linewidth samples,the measurement error is less than 3%.The repeatability test results show that the measurement repeatability of the system is good.Finally,the influencing factors of resonance linewidth measurement results are analyzed,and the measurement uncertainty of the system is evaluated.