Patent US2506198A successfully refreshed from Google Patents.
US4720680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adjustable radio frequency coil for nuclear magnetic resonance imaging
Assignee: Mitsubishi Electric Corp
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Filing: 1987-02-09
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Granted: 1988-01-19
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Expires: 2007-02-09
Abstract
Abstract A radio frequency coil for a nuclear magnetic resonance imaging apparatus comprises a plurality of arcuate, plate-like H-shaped members which are disposed about a common axis so as to form a tube. The flanges of adjacent H-shaped members are electrically connected. The web of at least one of the H-shaped members is cut in two at its midportion to form two T-shaped plates, and the legs of the T-shaped plates are connected by capacitive coupling in a manner which allows the capacitance to be varied. A conventional variable capacitor can be used to vary the capacitance. Alternatively, each H-shaped member is divided into two T-shaped plates with overlapping legs. A dielectric material is provided between the overlapping portions, and the capacitance is varied by moving the T-shaped plates with respect to one another in the longitudinal direction of the tube so as to vary the size of the overlapping portions.
Inventors
- 👤 Susumu Nishihara
- 👤 Kiyoshi Yoda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:47
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/34046; G01R33/36; G01R33/3628
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
155 words
A radio frequency coil for a nuclear magnetic resonance imaging apparatus comprising: one or more pairs of plate-like H-shaped electrically conducting members, each of said H-shaped members having a longitudinally-extending web and two flange portions at opposite ends of and perpendicular to said web, each of said H-shaped members being bent into the shape of an arc and being symmetriclaly disposed about a common axis so as to form a tube, each of said webs being parallel to said axis and each of said flanges extending circumferentially around said tube towards one another, each flange being electrically connected to a flange of the adjacent H-shaped member, at least one of the H-shaped members of each pair being transversely divided in two at the midportion of its web so as to form two T-shaped plates; and variable capacitor means having a variable capacitance for electrically connecting the legs of said two T-shaped plates by capacitive coupling.
Claim 2
Dependent Claim
155 words
A radio frequency coil for a nuclear magnetic resonance imaging apparatus comprising: one or more pairs of plate-like H-shaped electrically conducting members, each of said H-shaped members having a longitudinally-extending web and two flange portions at opposite ends of and perpendicular to said web, each of said H-shaped members being bent into the shape of an arc and being symmetriclaly disposed about a common axis so as to form a tube, each of said webs being parallel to said axis and each of said flanges extending circumferentially around said tube towards one another, each flange being electrically connected to a flange of the adjacent H-shaped member, at least one of the H-shaped members of each pair being transversely divided in two at the midportion of its web so as to form two T-shaped plates; and variable capacitor means having a variable capacitance for electrically connecting the legs of said two T-shaped plates by capacitive coupling.
Claim 3
Dependent Claim
18 words
A radio frequency coil as claimed in claim 1, wherein said variable capacitor means comprises a variable capacitor.
Claim 4
Dependent Claim
152 words
A radio frequency coil as claimed in claim 1, wherein: each of said H-shaped members is divided transversely in two at the midportion of its web to form two T-shaped plates; the legs of the two T-shaped plates of each H-shaped member overlap in the longitudinal direction of the tube; said T-shaped plates are supported such that at least one of the two T-shaped plates of each H-shaped member can be moved with respect to the other T-shaped plate in the longitudinal direction of said tube so as to vary the area of the overlapping portion; and said adjustable capacitor means comprises the overlapping portions of the legs of said T-shaped plates, and a dielectric material which is disposed between the overlapping legs of the two T-shaped plates of each H-shaped member, said dielectric material being secured to the leg of only one of the two T-shaped plates of each H-shaped member.
Claim 5
Dependent Claim
24 words
A radio frequency coil as claimed in claim 3, wherein said dielectric material is selected from the group consisting of synthetic resins and porcelain.
Claim 6
Dependent Claim
21 words
A radio frequency coil as claimed in claim 1, wherein the flanges of adjacent H-shaped members are connected by pressure welding.
Claim 7
Dependent Claim
20 words
A radio frequency coil as claimed in claim 1, wherein the flanges of adjacent H-shaped members are connected by soldering.
Claim 8
Dependent Claim
21 words
A radio frequency coil as claimed in claim 1, wherein the flanges of adjacent H-shaped members are connected by electrical conductors.
Claim 9
Dependent Claim
21 words
A radio frequency coil as claimed in claim 1, wherein the flanges of adjacent H-shaped members are connected by capacitive coupling.
Claim 10
Dependent Claim
21 words
A radio frequency coil as claimed in claim 8, wherein the flanges of adjacent H-shaped members are connected by fixed capacitors.
Claim 11
Dependent Claim
19 words
A radio frequency coil as claimed in claim 1, wherein the transverse cross-sectional shape of said tube is circular.
Claim 12
Dependent Claim
19 words
A radio frequency coil as claimed in claim 1, wherein the transverse cross-sectional shape of said tube is elliptical.
Claim 13
Dependent Claim
40 words
A radio frequency coil as claimed in claim 11, wherein said tube comprises one pair of said H-shaped members which are disposed with their webs at opposite ends of the major axes of the transverse cross sections of said tube.
Claim 14
Dependent Claim
40 words
A radio frequency coil as claimed in claim 11, wherein said tube comprises one pair of said H-shaped members which are disposed with their webs at opposite ends of the minor axes of the transverse cross sections of said tube.
Claim 15
Dependent Claim
27 words
A radio frequency coil as claimed in claim 1, further comprising an electromagnetic shield which surrounds said H-shaped members and is coaxial with respect to said tube.
Claim 16
Dependent Claim
45 words
A radio frequency coil as claimed in claim 1, further comprising two electrically conducting rings which are coaxially disposed in said tube at opposite ends thereof within said flanges, said rings being electrically insulated from said tube, at least one of said rings being grounded.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-01-18 | 1991-07-20 | 1992-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-18 | 1995-07-20 | 1996-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-18 | 1999-07-20 | 2000-01-19 | $7700.00 | Window Closed / Lapsed |