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US4589422A
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Electromagnetic medical applicators
Assignee: NATIONAL RESEARCH DEVELOPMENT Corp 101 NEWINGTON CAUSEWAY LONDON SE1 6UP ENGLAND A BRITISH CORP
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Filing: 1984-02-03
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Granted: 1986-05-20
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Expires: 2004-02-03
Abstract
Abstract An electromagnetic medical applicator for heating tissue comprises a patch resonator (1) on a substrate (4) of dielectric material backed by a ground-plane (3), and having a layer (7) of dielectric material overlying the resonator inter alia to effect impedance-matching to tissue, in which the substrate includes a volume of magnetic material (5) adjacent the maximum-current region of the resonator in order to reduce the length of the resonator at its resonant frequency.
Inventors
- 👤 James R. James
- 👤 Reginald H. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:20
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/02; A61N1/04; A61N1/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
121 words
An electromagnetic medical applicator comprising: a laminar resonator, a conducting ground plane, a layer of an electromagnetic medium separating said resonator from said ground plane, and electrical connection means to said resonator and ground plane, said electromagnetic medium comprising separate volumes of magnetic material and of dielectric material with magnetic material located substantially only adjacent that region of the resonator where in use the resonator current is a maximum and said resonator being in intimate contact with said dielectric material adjacent that region of the resonator where in use the resonator current is a minimum, said magnetic material providing an improved path for the magnetic field associated with said current; and a layer comprising at least dielectric material overlying said resonator.
Claim 2
Dependent Claim
121 words
An electromagnetic medical applicator comprising: a laminar resonator, a conducting ground plane, a layer of an electromagnetic medium separating said resonator from said ground plane, and electrical connection means to said resonator and ground plane, said electromagnetic medium comprising separate volumes of magnetic material and of dielectric material with magnetic material located substantially only adjacent that region of the resonator where in use the resonator current is a maximum and said resonator being in intimate contact with said dielectric material adjacent that region of the resonator where in use the resonator current is a minimum, said magnetic material providing an improved path for the magnetic field associated with said current; and a layer comprising at least dielectric material overlying said resonator.
Claim 3
Dependent Claim
41 words
An applicator as claimed in claim 1 wherein the resonator is a patch resonator on a solid substrate constituting said electromagnetic medium and backed by said conducting ground-plane, with said magnetic material extending transversely to the polarisation direction of the resonator.
Claim 4
Dependent Claim
26 words
An applicator as claimed in claim 2 wherein the resonator is a half-wave patch resonator and said magnetic material underlies the central region of the resonator.
Claim 5
Dependent Claim
29 words
An applicator as claimed in claim 3 wherein the layer of dielectric material overlying the resonator has an ε-value which approximately matches that of tissue at the resonator frequency.
Claim 6
Dependent Claim
23 words
An applicator as claimed in claim 4 wherein the dielectric material of the substrate has approximately the same ε-value as said overlying layer.
Claim 7
Dependent Claim
26 words
An applicator as claimed in claim 1 wherein the resonator is a half-wave patch resonator and said magnetic material underlies the central region of the resonator.
Claim 8
Dependent Claim
29 words
An applicator as claimed in claim 6 wherein the layer of dielectric material overlying the resonator has an ε-value which approximately matches that of tissue at the resonant frequency.
Claim 9
Dependent Claim
24 words
An applicator as claimed in claim 7 wherein the dielectric material of the electromagnetic medium has approximately the same ε-value as said overlying layer.
Claim 10
Dependent Claim
25 words
An applicator as claimed in claim 1 wherein the resonator is a quarter-wave patch resonator and said magnetic material underlies one end of the resonator.
Claim 11
Dependent Claim
29 words
An applicator as claimed in claim 9 wherein the layer of dielectric material overlying the resonator has an ε-value which approximately matches that of tissue at the resonant frequency.
Claim 12
Dependent Claim
24 words
An applicator as claimed in claim 10 wherein the dielectric material of the electromagnetic medium has approximately the same ε-value as said overlying layer.
Claim 13
Dependent Claim
24 words
An applicator as claimed in claim 2 wherein the resonator is a quarter-wave patch resonator and magnetic material underlies one end of the resonator.
Claim 14
Dependent Claim
29 words
An applicator as claimed in claim 12 wherein the layer of dielectric material overlying the resonator has an ε-value which approximately matches that of tissue at the resonant frequency.
Claim 15
Dependent Claim
23 words
An applicator as claimed in claim 13 wherein the dielectric material of the substrate has approximately the same ε-value as said overlying layer.
References Cited (Backward Citations)
US3811128A
Cited
US4240445A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-19 | 1989-11-18 | 1990-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-19 | 1993-11-18 | 1994-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-19 | 1997-11-18 | 1998-05-20 | $7700.00 | Window Closed / Lapsed |