US5600243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetically shielded magnetic sensor with squid and ground plane
Assignee: Silicon Valley Bank Inc
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Filing: 1993-09-07
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Granted: 1997-02-04
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Expires: 2013-09-07
Abstract
Abstract A coupling structure for coupling a feedback signal to a superconducting quantum interference device (SQUID) by mutual inductance. In one embodiment the SQUID loop (A) is shielded from external magnetic fields perpendicular to it by a superconducting ground plane (B) at all points except for the pick-up loop (C). A feedback signal is coupled to the SQUID loop (A) by a feedback loop (D) which has a mutual inductance with the SQUID loop (A). During operation, the feedback loop (D) conducts a current in only one direction around the SQUID loop (A). This geometry ensures that the SQUID loop (A) is shielded from external magnetic fields, except at the pick-up loop (C), by the ground plane, and is balanced against fields parallel to the ground plane. The magnetic field produced by the current in the feedback coil (D) is small far from the SQUID (A). The feedback loop (D) is connected to exterior feedback electronics.
Inventors
- 👤 Mark S. Colclough
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:43
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/035; G01R33/0354; G01R33/0356; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/842; Y10S505/843; Y10S505/845; Y10S505/846
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
165 words
A magnetic sensor comprising: a superconducting ground plane; a SQUID comprising a pickup loop, a SQUID loop and at least one weak-link junction, said SQUID loop and said pickup loop lying in a single plane, said SQUID loop being displaced from said superconducting ground plane in a direction normal to the plane and substantially overlying said superconducting ground plane and said pick-up loop lying exterior to the area overlying said superconducting groundplane; and a feedback loop, said feedback loop being displaced from said superconducting ground plane and from said SQUID in a direction normal to the plane, said feedback loop substantially overlying said SQUID loop, and said feedback loop having a bifilar geometry and a mutual inductance with said SQUID loop wherein said feedback loop conducts a current in a direction around the feedback loop, said current producing a magnetic field at each point along said feedback loop, and the sum of said magnetic fields being approximately equal at a distance from said feedback loop.
Claim 2
Dependent Claim
165 words
A magnetic sensor comprising: a superconducting ground plane; a SQUID comprising a pickup loop, a SQUID loop and at least one weak-link junction, said SQUID loop and said pickup loop lying in a single plane, said SQUID loop being displaced from said superconducting ground plane in a direction normal to the plane and substantially overlying said superconducting ground plane and said pick-up loop lying exterior to the area overlying said superconducting groundplane; and a feedback loop, said feedback loop being displaced from said superconducting ground plane and from said SQUID in a direction normal to the plane, said feedback loop substantially overlying said SQUID loop, and said feedback loop having a bifilar geometry and a mutual inductance with said SQUID loop wherein said feedback loop conducts a current in a direction around the feedback loop, said current producing a magnetic field at each point along said feedback loop, and the sum of said magnetic fields being approximately equal at a distance from said feedback loop.
Claim 3
Dependent Claim
19 words
The magnetic sensor of claim 1 wherein said feedback loop is intermediate said SQUID and said superconducting ground plane.
Claim 4
Dependent Claim
19 words
The magnetic sensor of claim 1 wherein said SQUID is intermediate said feedback loop and said superconducting ground plane.
Claim 5
Dependent Claim
52 words
The magnetic sensor of claim 1 further comprising a second superconducting ground plane, said second superconducting ground plane being displaced from said SQUID, said feedback loop, and said superconducting ground plane in a direction normal to the plane, and said SQUID and said feedback loop lying between the two superconducting ground planes.
Claim 6
Dependent Claim
19 words
The magnetic sensor of claim 1 further comprising an electrical connection between said SQUID and said superconducting ground plane.
Claim 7
Dependent Claim
52 words
The magnetic sensor of claim 2 further comprising a second superconducting ground plane, said second superconducting ground plane being displaced from said SQUID, said feedback loop, and said superconducting ground plane in a direction normal to the plane, and said SQUID and said feedback loop lying between the two superconducting ground planes.
Claim 8
Dependent Claim
52 words
The magnetic sensor of claim 3 further comprising a second superconducting ground plane, said second superconducting ground plane being displaced from said SQUID, said feedback loop, and said superconducting ground plane in a direction normal to the plane, and said SQUID and said feedback loop lying between the two superconducting ground planes.
Claim 9
Dependent Claim
19 words
The magnetic sensor of claim 2 further comprising an electrical connection between said SQUID and said superconducting ground plane.
Claim 10
Dependent Claim
19 words
The magnetic sensor of claim 3 further comprising an electrical connection between said SQUID and said superconducting ground plane.
References Cited (Backward Citations)
EP0313132A2
Cited
US5012190A
Cited
EP0327123A2
Cited
US5319307A
Cited
US5185527A
Cited
US5287057A
Cited
EP0567386A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-02-04 | 2000-08-05 | 2001-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-02-04 | 2004-08-05 | 2005-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-02-04 | 2008-08-05 | 2009-02-04 | $7700.00 | Window Closed / Lapsed |