US3693072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferromagnetic resonance magnetometer
Assignee: United States Department of the Navy
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Filing: 1967-08-25
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Granted: 1972-09-19
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Expires: 1987-08-25
Abstract
Abstract A magnetometer having a thin-film sensor positioned near or at the end of a transmission line and biased near its ferromagnetic resonance. An electromagnetic signal is applied to the thin-film sensor. The reflected portion of this signal is amplitude modulated by the influence of an external magnetic field on the thin-film sensor, and then detected to provide a measure of the external magnetic field.
Inventors
- 👤 Henry R Irons
- 👤 Leonard J Schwee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:44
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/24
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
139 words
A ferromagnetic resonance magnetometer comprising: a thin-film sensor formed of ferromagnetic material, means biasing said thin-film sensor near its ferromagnetic resonance by a ceramic permanent magnet with an initial permeability near unity, means generating a fixed period, extremely high frequency electromagnetic signal which is modulated when said sensor defects an external magnetic field, transmission line means coupled to said generating means and to said thin-film sensor and impedance matched to said thin-film sensor for applying said generated electromagnetic signal to said sensor and for transmitting the reflected signal therefrom, means responsive to the amplitude of said reflected signal as it varies when said ferromagnetic resonance is shifted by said external magnetic field, and means coupled to said sensor and said reflected signal responsive means for effecting the unidirectional signal flow from said sensor to said reflected signal responsive means.
Claim 2
Dependent Claim
139 words
A ferromagnetic resonance magnetometer comprising: a thin-film sensor formed of ferromagnetic material, means biasing said thin-film sensor near its ferromagnetic resonance by a ceramic permanent magnet with an initial permeability near unity, means generating a fixed period, extremely high frequency electromagnetic signal which is modulated when said sensor defects an external magnetic field, transmission line means coupled to said generating means and to said thin-film sensor and impedance matched to said thin-film sensor for applying said generated electromagnetic signal to said sensor and for transmitting the reflected signal therefrom, means responsive to the amplitude of said reflected signal as it varies when said ferromagnetic resonance is shifted by said external magnetic field, and means coupled to said sensor and said reflected signal responsive means for effecting the unidirectional signal flow from said sensor to said reflected signal responsive means.
Claim 3
Dependent Claim
17 words
A ferromagnetic resonance magnetometer as in claim 1 wherein said unidirectional signal flow means is a circulator.
Claim 4
Dependent Claim
25 words
A ferromagnetic resonance magnetometer as in claim 1 wherein said responsive means comprises a detector circuit for detecting the voltage amplitude of said reflected signal.
Claim 5
Dependent Claim
45 words
A ferromagnetic resonance magnetometer as in claim 3 wherein said responsive means further comprises a low pass filter for smoothing the output of said detector circuit, an amplifier for amplifying said smoothed output, and an oscilloscope for directly determining the magnitude of said magnetic field.
Claim 6
Dependent Claim
29 words
A ferromagnetic resonance magnetometer as in claim 1 wherein a high pass filter and a common mode rejector are inserted into said transmission line means for eliminating induced currents.
Claim 7
Dependent Claim
38 words
A ferromagnetic resonance magnetometer as in claim 1 wherein said thin-film sensor comprises a thin-film wound around a fine wire, said wire coupled to said transmission line, whereby said transmission line is impedance matched to said thin-film sensor.
Claim 8
Dependent Claim
49 words
A ferromagnetic resonance magnetometer as in claim 1 wherein said thin-film sensor comprises a stack of thin-films, each film mounted on a thin substrate, said thin-films coupled to an end of said transmission line in a shorted loop whereby said transmission line is impedance matched to said thin-film sensor.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |