# US 2025/0085366 A1 · Magnetic Permeability Measurement Probe and Magnetic Permeability Measurement Device Using the Probe > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0085366 A1 - Document ID: US20250085366A1 - Status: Published application - Kind: A1 - Application number: 18/958,802 - Filed: 2024-11-25 - Published: 2025-03-13 - Earliest claimed: 2022-05-27 - Assignees: Tohoku University - Applicants: Tohoku University - Inventors: Shin Yabukami; Kazuhiko Okita; Yoshiyuki Watanabe - Web page: https://patentgrep.com/patent/US20250085366A1 ## CPC - G01R 33/1223: {Measuring permeability, i.e. permeameters (G01R33/14 takes precedence)} - G01N 27/72: by investigating magnetic variables - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The probe for measuring a magnetic permeability of a magnetic material includes a transmission line body including a strip-shaped strip conductor formed on a front surface of a dielectric substrate and a ground conductor formed on the front surface or a back surface of the dielectric substrate; a first connector connected to one end of each of the strip conductor and the ground conductor; and a second connector connected to the other end of each of the strip conductor and the ground conductor, in which the strip conductor includes a first length portion including a portion connected to the first connector on one end side, a second length portion including a portion connected to the second connector at the other end, and a third length portion extending between the first length portion and the second length portion, and the third length portion includes a current deviation prevention unit. ## Claims ### Claim 1 A probe for measuring a magnetic permeability of a magnetic material, the probe comprising: a transmission line body comprising a strip-shaped strip conductor formed on a front surface of a dielectric substrate and a ground conductor formed on the front surface or a back surface of the dielectric substrate; a first connector connected to one end of each of the strip conductor and the ground conductor; and a second connector connected to the other end of each of the strip conductor and the ground conductor, wherein the strip conductor comprises a first length portion comprising a portion connected to the first connector on one end side, a second length portion comprising a portion connected to the second connector at the other end, and a third length portion extending between the first length portion and the second length portion, and the third length portion comprises a current deviation prevention unit. ### Claim 2 (depends on 1) The probe according to claim 1, wherein the transmission line body is a microstrip line or a coplanar line. ### Claim 3 (depends on 1) The probe according to claim 1, wherein the current deviation prevention unit comprises at least one slit extending in a length direction of the strip conductor. ### Claim 4 (depends on 3) The probe according to claim 3, wherein the slit comprises a plurality of slits parallel to each other and extending in the length direction of the strip conductor. ### Claim 5 (depends on 4) The probe according to claim 4, wherein the plurality of slits are arranged at an equal interval in a width direction. ### Claim 6 (depends on 4) The probe according to claim 4, wherein the plurality of slits are arranged at different intervals in a width direction. ### Claim 7 (depends on 6) The probe according to claim 6, wherein the plurality of slits are arranged such that the intervals increase from both end sides toward a center portion in the width direction. ### Claim 8 (depends on 7) The probe according to claim 7, wherein the strip conductor is formed such that the center portion has a larger film thickness than the both end sides in the width direction. ### Claim 9 (depends on 4) The probe according to claim 4, wherein the plurality of slits are formed with a same width dimension. ### Claim 10 (depends on 4) The probe according to claim 4, wherein the plurality of slits are formed with different width dimensions. ### Claim 11 (depends on 10) The probe according to claim 10, wherein the plurality of slits are formed and arranged such that the width dimensions thereof increase from both end sides toward a center portion in the width direction. ### Claim 12 (depends on 4) The probe according to claim 4, wherein the third length portion has a larger width dimension in a width direction than the first length portion and the second length portion, the plurality of slits comprises a first slit on relatively both end sides in the width direction and a second slit on a center side in the width direction relative to the first slit, and a first interval extending in the length direction from a length direction end of the first slit to a width direction edge of the third length portion is shorter than a second interval extending in the length direction from a length direction end of the second slit to the width direction edge of the third length portion. ### Claim 13 (depends on 12) The probe according to claim 12, wherein the first slit and the second slit have a same length, and the width direction edge of the third length portion is formed in a tapered shape, and a length dimension of the third length portion decreases from the center side toward both end sides in the width direction. ### Claim 14 (depends on 12) The probe according to claim 12, wherein a length dimension of the third length portion is same from the center side toward both end sides in the width direction, and a length dimension of the first slit is longer than a length dimension of the second slit. ### Claim 15 (depends on 1) The probe according to claim 1, wherein the current deviation prevention unit is configured to reduce an electric resistance from an end to an inner side in a width direction of the third length portion perpendicular to a length direction of the strip conductor. ### Claim 16 (depends on 15) The probe according to claim 15, wherein in the current deviation prevention unit, the strip conductor is made of a plurality of materials having different electric resistances. ### Claim 17 (depends on 15) The probe according to claim 15, wherein in the current deviation prevention unit, a material having a conductivity different from a conductivity of the strip conductor is provided on the strip conductor. ### Claim 18 (depends on 15) The probe according to claim 15, wherein in the current deviation prevention unit, a film thickness of the strip conductor is larger on the inner side than on the end. ### Claim 19 (depends on 15) The probe according to claim 15, wherein the current deviation prevention unit is doped with a substance that changes a conductivity of the strip conductor. ### Claim 20 (depends on 1) A magnetic permeability measurement device, comprising: the probe according to claim 1; a magnetic field application unit configured to apply a magnetic field to the magnetic material; a signal meter connected to the probe via a cable, and configured to measure a permeability coefficient signal both with and without application of the magnetic field by the magnetic field application unit; and a processing unit configured to acquire a magnetic permeability of the magnetic material by numerical value analysis calculation processing based on the permeability coefficient signal measured by the signal meter.