Measuremrnt Of Complex Permeability Of Magnetic Thin Film By Short Circuit Microstrip Line Method

The magnetic thin film can be widely used in various fields of the high-speedelectronics industry, such as: information storage, electromagnetic compatibility,magnetic field sensors, microwave communications devices. With the miniaturizationand the development of the high-frequency magnetic thin film devices, the measurementof magnetic thin film magnetic high frequency is particularly important.The high microwave frequency characteristics, temperature characteristics, andferromagnetic resonance linewidth of the magnetic material are one of the key elementsof the research at home and abroad. The complex permeability of magnetic material isbasic parameter of the material, and its accurate measurement is the key of the research,design and application of the magnetic device. This paper is aimed at the measuringtechnology of the complex permeability of magnetic material, carried out the followingwork.Firstly, the formula of short microstrip line method based on transmission linetheory is derived, and electromagnetic simulation software HFSS simulation analysis ofthe measurement model, based on the simulation results demonstrate the feasibility ofthe test method. Then specifically research the impact of the test sample size and theplacement of the sample during the test. The results show that: the width of theconductor of the microstrip line on the test fixture is5mm; air dielectric layer having athickness of1mm; bearer sample film thickness of the substrate that loads sample filmis not too thick, this paper choose the thickness is0.5mm, the width of the substrateshould be larger than the width of the upper conductor of the microstrip line, in thisarticle is selected as10mm; the dielectric substrate against the placement of shortsurfaces.Then through the measurement of the NiFe film sample, successfully extracted thevalue of the complex magnetic permeability of the sample film. Based on the value ofthe complex magnetic permeability, indicates that NiFe thin film after the heat treatmentdue to the anisotropy field becomes small, so the ferromagnetic resonance frequency islow; and when the static field is applied, the ferromagnetic resonance frequency point with increasing the strength of the static magnetic field becomes large; In this paper, thedesigned measuring method in anisotropic thin films of complex permeability valuesand basic consistent with measurement results from the national university ofSingapore.Finally, used the Guide of Matlab, produced a graphical interface, and shows theinterface of project operation process, has realized the reading, analysis, calculation anddrawing of the visualization for the measured.