US3560695A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave applicator employing a flat multimode cavity
Assignee: Varian Medical Systems Inc
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Filing: 1969-02-17
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Granted: 1971-02-02
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Expires: 1989-02-17
Abstract
Abstract A microwave applicator is disclosed which is especially useful for treating thin films of dielectric material. The microwave applicator includes a flat multimode cavity having a pair of parallel broad walls closed on their sides by narrow sidewalls. The cavity is preferably excited in one of the TEl,m,n and/or TMl,m,n classes of modes, where l is l, with an electric field vector of the excited classes of modes being generally parallel to the broad walls and of relatively high intensity in the midplane of the cavity. The cavity is reactively loaded with periodic elements for concentrating the frequencies of the aforementioned classes of modes near the frequency of operation to facilitate mode-stirring and to improve the time average impedance match to the cavity during mode stirring.
Inventors
- 👤 Norman H Williams
- 👤 Jerome R White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:16
CPC Classifications
H; H01; H01P; H01P3/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
151 words
In a microwave applicator, means forming a microwave cavity resonator having a pair of opposed broad walls closed on their sides by narrow sidewalls, the electrical spacing between said pair of broad walls of said cavity being greater than one-half wavelength and less than one wavelength at the frequencies of operation of said cavity, means for exciting the TEl,m,n and TMl, m,n classes of modes in said cavity where l is 1 and is in the direction extending between said pair of walls to produce an electric field of high intensity in a treatment zone between and generally parallel to said broad walls of said cavity, and means along at least one of said broad walls forming periodic inductive reactive loading of said cavity to produce a periodic reactively loaded cavity resonator having a higher mode density within its operating pass band than an unloaded cavity of the same physical dimensions.
Claim 2
Dependent Claim
151 words
In a microwave applicator, means forming a microwave cavity resonator having a pair of opposed broad walls closed on their sides by narrow sidewalls, the electrical spacing between said pair of broad walls of said cavity being greater than one-half wavelength and less than one wavelength at the frequencies of operation of said cavity, means for exciting the TEl,m,n and TMl, m,n classes of modes in said cavity where l is 1 and is in the direction extending between said pair of walls to produce an electric field of high intensity in a treatment zone between and generally parallel to said broad walls of said cavity, and means along at least one of said broad walls forming periodic inductive reactive loading of said cavity to produce a periodic reactively loaded cavity resonator having a higher mode density within its operating pass band than an unloaded cavity of the same physical dimensions.
Claim 3
Dependent Claim
60 words
The apparatus of claim 1 wherein said periodic reactive loading means comprises a two-dimensional clustered array of hollow conductive tubes having their longitudinal axes directed generally perpendicular to the plane of said broad walls of said cavity with the inner ends of said tubes defining the inner conductive boundary of at least one of said broad walls of said cavity.
Claim 4
Dependent Claim
37 words
The apparatus of claim 2 wherein the inside transverse dimensions of said hollow tubes are dimensioned below cutoff for TE and TM wave energy propagating axially of said tubes at the operating frequency of said cavity resonator.
Claim 5
Dependent Claim
19 words
The apparatus of claim 3 including means forming a resistive termination at the outer ends of said hollow tubes.
Claim 6
Dependent Claim
40 words
The apparatus of claim 2 wherein both broad walls of said cavity includes said array of conductive tubes with the inner ends of said tubes defining the inner conductive boundary of both of said broad walls of said cavity resonator.
Claim 7
Dependent Claim
19 words
The apparatus of claim 2 wherein said conductive tubes have a length in excess of their characteristic cross-sectional dimension.
Claim 8
Dependent Claim
15 words
The apparatus of claim 2 wherein said conductive tubes are of generally square cross section.
Claim 9
Dependent Claim
34 words
The apparatus of claim 1 wherein said reactive loading means includes an array of generally parallel fins with the plane of the fins being generally perpendicular to said broad walls of said cavity resonator.
Claim 10
Dependent Claim
34 words
The apparatus of claim 1 wherein said reactive loading means includes an array of generally parallel rods with the axes of the rods being generally perpendicular to the broad walls of said cavity resonator.
Claim 11
Dependent Claim
30 words
The apparatus of claim 1 wherein said reactive loading means includes an array of generally parallel slots formed in at least one of said broad walls of said cavity resonator.
Claim 12
Dependent Claim
30 words
The apparatus of claim 1 wherein said reactive loading means includes a corrugated structure with said corrugations projecting from one broad wall toward the opposed broad wall of said cavity.
Claim 13
Dependent Claim
26 words
The apparatus of claim 1 wherein said reactive loading means comprises an array of apertures in at least one of said broad walls of said cavity.
Claim 14
Dependent Claim
22 words
The apparatus of claim 1 wherein said reactive loading means provides periodic loading of said cavity along both its width and length.
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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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |