Permeability Measurements of Magnetic Thin Films using Shielded Short-Circuited Microstrip Lines

Abstract

A method to measure wideband permeability was developed for 5-mm-square magnetic thin film from 0.1 to 10GHz by using a shielded short-circuited microstrip line as the test fixture. The S11 parameters of the test fixturewere measured with a vector network analyzer (VNA). The permeability was derived, based on the lumped element approximation, by comparing S11s with S11os which corresponded to without and with a strong magnetic field parallel to the microwave magnetic field caused by the microstrip line. In this case, the influence of substrate on which the thin film prepared could not be neglected due to the small gap between the microstrip line and the substrate. We introduced a method to derive an effective permittivity e caused by the substrate by comparing S11o of blank fixture with S11os of fixture with sample under a strong static magnetic field. We also propose a method of determining whether the lumped element approximation is valid or not.

Dynamical magnetic behavior of anisotropic spinel-structured ferrite for GHz technologies

“…The complex permeability of the Ni 0.5 Zn 0.5 Fe 2 O 4 -powder/polymer composite sheet measured by the short-circuited MSL method 10 , 15 , 19 is shown in Fig. 3 a where the real ( ) and imaginary ( ) parts of the relative permeability are plotted against the frequency of electromagnetic wave irradiated up to 30 GHz.…”

“…In conclusion, we applied two different originally developed techniques, short-circuited MSL 10 , 15 , 19 and MSL-probe 11 , 20 methods, to a Ni 0.5 Zn 0.5 Fe 2 O 4 powder/polymer composite sheet prepared from high-quality Ni 0.5 Zn 0.5 Fe 2 O 4 ceramic powder. Although the two techniques are based on different experimental setups/systems, the dynamic permeability behaviors at GHz bands are essentially consistent.…”

“…In this study, we evaluate the dynamic permeability behavior of ferrites under the irradiation of an electromagnetic wave of GHz frequency through two different originally developed measurement techniques, (i) short-circuited MSL 10 , 15 , 19 , and (ii) MSL-probe 11 , 20 methods. Our aim is to provide a comprehensive understanding of the dynamical magnetic behaviors of ferrites in the GHz region.…”

Permeability Measurement up to 30 GHz of a Magnetically Isotropic Thin Film Using a Short-Circuited Coaxial Line

“…The effective magnetic permeability is derived using the field method from the input admittances for the equivalent circuits shown in figures. 6 and 7 in the usual way: please refer to previous papers 1,9,10,11) for details.…”

“…We have already reported such measurement results for the 10-30 GHz band using short-circuited microstrip line test fixtures. 1,2) Improving the present fixtures is crucial for performing measurements at higher frequencies. On the other hand, a short-circuited coaxial line can also be used, without the need to consider the external noise due to a perfectly shielded structure.…”