US4680548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radio frequency field coil for NMR
Assignee: General Electric Co
•
Filing: 1986-07-16
•
Granted: 1987-07-14
•
Expires: 2006-07-16
Abstract
Abstract In one embodiment, referred to as the "high-pass" version, the radio frequency (RF) coil is made up of two conductive loop elements, each including serially-connected capacitors. The loop elements are electrically interconnected by axial conductive segments having inherent inductances associated therewith. Electrically, the coil can be viewed as a slow wave delay line structure wrapped around a cylinder and connected to itself. The coil can be energized by connecting a source of RF power across one of the capacitors in the loop elements. In another embodiment, termed the "band-pass" version, the axial conductive segments, as well as the conductive loop elements, are provided with capacitors.
Inventors
- 👤 William A. Edelstein
- 👤 John F. Schenck
- 👤 Otward M. Mueller
- 👤 Cecil E. Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:28
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/36; G01R33/3628; G01R33/34; G01R33/34046; G01R33/34076
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
60 words
An NMR radio frequency (RF) coil comprising: a pair of conductive loop elements spaced along a common longitudinal axis, each of said conductive loop elements including a plurality of serially-connected capacitive elements spaced along the peripheries thereof; and a plurality of axial conductive segments electrically interconnecting said conductive loop elements at points between adjacent ones of said serially-connected capacitive elements.
Claim 2
Dependent Claim
60 words
An NMR radio frequency (RF) coil comprising: a pair of conductive loop elements spaced along a common longitudinal axis, each of said conductive loop elements including a plurality of serially-connected capacitive elements spaced along the peripheries thereof; and a plurality of axial conductive segments electrically interconnecting said conductive loop elements at points between adjacent ones of said serially-connected capacitive elements.
Claim 3
Dependent Claim
22 words
The NMR RF coil of claim 1 wherein each of said axial conductive segments includes a capacitive element connected in series therewith.
Claim 4
Dependent Claim
103 words
The NMR RF coil of claim 1 further comprising a first means for exciting said RF coil across a first input capacitive element in one of said pair of conductive loops with a first RF power source oscillating at the frequency of the desired resonant mode so as to produce a current distribution proportional to ##EQU11## in said conductive loop elements, and to produce current distribution which will vary according to ##EQU12## ps through said axial conductive segments, wherein k is an integer between 1 and the total number of coil sections N, starting with k=1 at the section having the input capacitor.
Claim 5
Dependent Claim
70 words
The NMR RF coil of claim 3 further comprising a second means for exciting said RF coil across a second input capacitive element separated by 90° along the periphery of said one of the conductive loop elements from said first input capacitive element with a second RF power source at the frequency of the desired resonant mode, said power sources being electrically 90° out of phase relative to one another.
Claim 6
Dependent Claim
68 words
The NMR RF coil of claim 1 wherein said coil is constructed on a cylindrical coil form adapted for receiving therein an NMR subject and wherein said axial conductive segments comprise thin conductors so that large gaps are created between adjacent segments, said coil form having slots formed in the region of at least one of said gaps thereby to improve ventilation and visibility of the NMR subject.
Claim 7
Dependent Claim
57 words
The NMR RF coil of claim 1 wherein a plurality of said capacitive elements comprise input elements for an equal plurality of RF power amplifiers, the outputs of said amplifiers being phased relative to one another so that collectively the currents induced in said axial and loop conductive elements result in a linearly polarized RF magnetic field.
Claim 8
Dependent Claim
57 words
The NMR RF coil of claim 1 wherein a plurality of said capacitive elements comprise input elements for an equal plurality of RF power amplifiers, the outputs of said amplifiers being phased relative to one another so that collectively the currents induced in said axial and loop conductive elements result in a circularly polarized RF magnetic field.
Claim 9
Dependent Claim
74 words
An NMR radio frequency (RF) coil comprising a high-pass slow-wave delay line structure which is configured as a ladder network, said delay line structure being formed into a substantially cylindrical geometry and being connected to itself at its ends, wherein the side elements of the ladder network are coincident with the cylinder circumference, while the ladder rung elements are disposed lengthwise along the cylinder surface substantially parallel to the longitudinal axis of the cylinder.
Claim 10
Dependent Claim
74 words
An NMR radio frequency (RF) coil comprising a high-pass slow-wave delay line structure which is configured as a ladder network, said delay line structure being formed into a substantially cylindrical geometry and being connected to itself at its ends, wherein the side elements of the ladder network are coincident with the cylinder circumference, while the ladder rung elements are disposed lengthwise along the cylinder surface substantially parallel to the longitudinal axis of the cylinder.
Claim 11
Dependent Claim
75 words
The NMR RF coil of claim 8 wherein the side elements of the ladder network comprising a pair of conductive loop elements spaced along a common longitudinal axis, each of said conductive loop elements including a plurality of serially-connected capacitive elements spaced along the peripheries thereof, and wherein the ladder rung elements comprise a plurality of axial conductive segments electrically interconnecting said conductive loop elements at points between adjacent ones of said serially-connected capacitive elements.
Claim 12
Dependent Claim
74 words
An NMR radio frequency (RF) coil comprising a band-pass slow-wave delay line structure which is configured as a ladder network, said delay line structure being formed into a substantially cylindrical geometry and being connected to itself at its ends, wherein the side elements of the ladder network are coincident with the cylinder circumference, while the ladder rung elements are disposed lengthwise along the cylinder surface substantially parallel to the longitudinal axis of the cylinder.
Claim 13
Dependent Claim
74 words
An NMR radio frequency (RF) coil comprising a band-pass slow-wave delay line structure which is configured as a ladder network, said delay line structure being formed into a substantially cylindrical geometry and being connected to itself at its ends, wherein the side elements of the ladder network are coincident with the cylinder circumference, while the ladder rung elements are disposed lengthwise along the cylinder surface substantially parallel to the longitudinal axis of the cylinder.
Claim 14
Dependent Claim
92 words
The NMR RF coil of claim 10 wherein the side elements of the ladder network comprise a pair of conductive loop elements spaced along a common longitudinal axis, each of said conductive loop elements including a plurality of serially-connected capacitive elements spaced along the peripheries thereof, and wherein the ladder rung elements comprise a plurality of axial conductive segments electrically interconnecting said conductive loop elements at points between adjacent ones of said serially-connected capacitive elements, wherein each of said axial conductive segments includes at least one capacitive element connected in series therewith.
Claim 15
Dependent Claim
57 words
An NMR radio frequency (RF) coil comprising: a pair of conductive loop elements spaced along a common longitudinal axis, each of said conductive loop elements including a plurality of serially-connected capcitive elements spaced along the peripheries thereof; and a plurality of axial conductive segments electrically interconnecting said conductive loop elements at points between said serially-connected capacitive elements.
Claim 16
Dependent Claim
57 words
An NMR radio frequency (RF) coil comprising: a pair of conductive loop elements spaced along a common longitudinal axis, each of said conductive loop elements including a plurality of serially-connected capcitive elements spaced along the peripheries thereof; and a plurality of axial conductive segments electrically interconnecting said conductive loop elements at points between said serially-connected capacitive elements.
Claim 17
Dependent Claim
48 words
The NMR RF coil of one of claims 1, 8, 10 or 12 wherein said coil is constructed on a cylindrical coil form adapted for receiving therein an NMR subject, said coil form having a slot formed therein thereby to improve ventilation and visibility of the NMR subject.
Claim 18
Dependent Claim
67 words
The NMR RF coil of one of claims 9, 11 or 12 wherein a plurality of said capacitive elements in said conductive loop elements comprise input elements for an equal plurality of RF power amplifier, the outputs of said amplifiers being phased relative to one another so that collectively the currents induced in said axial and loop conductive elements result in a linearly polarized RF magnetic field.
Claim 19
Dependent Claim
67 words
The NMR RF coil of one of claims 9, 11 or 12 wherein a plurality of said capacitive elements in said conductive loop elements comprise input elements for an equal plurality of RF power amplifiers, the outputs of said amplifiers being phased relative to one another so that collectively the currents induced in said axial and loop conductive elements result in a circularly polarized RF magnetic field.
Claim 20
Dependent Claim
77 words
The NMR RF coil of one of claims 9, 11 or 12 further comprising a first means for exciting said RF coil across a first input capacitive element in one of said pair of conductive loops with a first RF power source oscillating at the frequency of the desired resonant mode so as to produce a current distribution proportional to ##EQU13## in said conductive loop elements, and to produce current distribution which will vary according to ##EQU14##
Claim 21
Dependent Claim
70 words
The NMR RF coil of claim 16 further comprising a second means for exciting said RF coil across a second input capacitive element separated by 90° along the periphery of said one of the conductive loop elements from said first input capacitive element with a second RF power source at the frequency of the desired resonant mode, said power sources being electrically 90° out of phase relative to one another.
References Cited (Backward Citations)
CH461844A
Cited
US3603871A
Cited
US3771055A
Cited
US4052661A
Cited
US4506224A
Cited
US4450408A
Cited
US4545384A
Cited
JPS60346A
Cited
US4607225A
Cited
US4563648A
Cited
US4581580A
Cited
US4594566A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-13 | 1991-01-12 | 1991-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-13 | 1995-01-12 | 1995-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-13 | 1999-01-12 | 1999-07-14 | $7700.00 | Window Closed / Lapsed |