Title:
STRUCTURE WITH SWITCHABLE MAGNETIC PROPERTIES
Document Type and Number:
WIPO Patent Application WO2001067549
Kind Code:
A3
Abstract:
A structure (40) with switchable magnetic properties comprises: an array of capacitive elements (44) in which each capacitive element (44) includes a low resistance conducting path and is such that a magnetic component (H) of electromagnetic radiation (12) lying within a predetermined frequency band induces an electrical current (j) to flow around said path and through said associated element (44). The size of the elements (44) and their spacing (a) apart are selected such as to provide a predetermined permeability ( mu ) in response to said received electromagnetic radiation (12). Each capacitive element (44) comprises a plurality of stacked planar sections (42) each of which comprises at least two concentric spiral conducting members or tracks (46, 48) which are electrically insulated from each other. A switchable permittivity material, such as Barium Strontium Titanate (BST) is provided between the tracks. The magnetic properties of the structure are switched by applying a dc electrical potential between the conducting tracks.
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Inventors:
WILTSHIRE MICHAEL CHARLES KEOG (GB)
Application Number:
PCT/GB2001/000957
Publication Date:
May 02, 2002
Filing Date:
March 06, 2001
Export Citation:
Assignee:
MARCONI CASWELL LTD (GB)
WILTSHIRE MICHAEL CHARLES KEOG (GB)
WILTSHIRE MICHAEL CHARLES KEOG (GB)
International Classes:
G01R33/422; A61B5/055; G01R33/3415; H01Q3/44; H01Q15/00; H01Q15/14; H05K9/00; (IPC1-7): H01Q15/00; H01Q15/10; H01Q15/14
Domestic Patent References:
| WO2000041270A1 | 2000-07-13 | |||
| WO1999018631A1 | 1999-04-15 |
Foreign References:
| US5223849A | 1993-06-29 |
Other References:
PENDRY J B ET AL: "MAGNETISM FROM CONDUCTORS AND ENHANCED NONLINEAR PHENOMENA", IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, IEEE INC. NEW YORK, US, vol. 47, no. 11, November 1999 (1999-11-01), pages 2075 - 2084, XP000865104, ISSN: 0018-9480
WILTSHIRE M C K ET AL: "Microstructured magnetic materials for RF flux guides in magnetic resonance imaging", SCIENCE, AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE,, US, vol. 291, no. 5505, 2 February 2001 (2001-02-02), pages 849 - 851, XP002169173, ISSN: 0036-8075
KWIAT D ET AL: "A DECOUPLED COIL DETECTOR ARRAY FOR FAST IMAGE ACQUISITION IN MAGNETIC RESONANCE IMAGING", MEDICAL PHYSICS, AMERICAN INSTITUTE OF PHYSICS. NEW YORK, US, vol. 18, no. 2, 1 March 1991 (1991-03-01), pages 251 - 265, XP000228811, ISSN: 0094-2405
WILTSHIRE M C K ET AL: "Microstructured magnetic materials for RF flux guides in magnetic resonance imaging", SCIENCE, AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE,, US, vol. 291, no. 5505, 2 February 2001 (2001-02-02), pages 849 - 851, XP002169173, ISSN: 0036-8075
KWIAT D ET AL: "A DECOUPLED COIL DETECTOR ARRAY FOR FAST IMAGE ACQUISITION IN MAGNETIC RESONANCE IMAGING", MEDICAL PHYSICS, AMERICAN INSTITUTE OF PHYSICS. NEW YORK, US, vol. 18, no. 2, 1 March 1991 (1991-03-01), pages 251 - 265, XP000228811, ISSN: 0094-2405
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