US3586971A
Expired / Lapsed
US
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Microwave apparatus for ascertaining changes in dielectric properties utilizing a slow wave structure
Assignee: Canadian Patents and Development Ltd
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Filing: 1969-02-10
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Granted: 1971-06-22
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Expires: 1989-02-10
Abstract
Abstract This apparatus for the determination of the dielectric properties, including moisture content, of substances utilizes slow wave resonance shift in a slow wave structure due to variations in the dielectric properties of specimen of substances disposed parallel to the axis of the structure. It is not necessary to utilize the prior known techniques involving the measurement of the attenuation of microwave energy.
Inventors
- 👤 Renato G Bosisio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:22
CPC Classifications
G; G01; G01N; G01N22/00; G01N22/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
141 words
Apparatus for ascertaining changes in the dielectric property K of a substance, said apparatus comprising: i. a periodic slow wave structure comprising a detector head having one side electrically open to said substance whose RF field lines, in operation, link into said substance, ii. means producing a microwave signal, iii. means for feeding said microwave signal, consisting essentially of frequency-modulated electromagnetic waves, into said sloW wave structure, and to extract said signal therefrom, iv. means for sweeping the microwave signal through a resonant frequency fo, for a selected mode of resonance, upon linking the RF lines with a specimen of said substance having a predetermined value of K, and v. means for measuring changes in the resonance frequency Delta fo, for the same mode of resonance, in response to different specimens of said substance having individual values of K1, K2 ---Kn.
Claim 2
Dependent Claim
141 words
Apparatus for ascertaining changes in the dielectric property K of a substance, said apparatus comprising: i. a periodic slow wave structure comprising a detector head having one side electrically open to said substance whose RF field lines, in operation, link into said substance, ii. means producing a microwave signal, iii. means for feeding said microwave signal, consisting essentially of frequency-modulated electromagnetic waves, into said sloW wave structure, and to extract said signal therefrom, iv. means for sweeping the microwave signal through a resonant frequency fo, for a selected mode of resonance, upon linking the RF lines with a specimen of said substance having a predetermined value of K, and v. means for measuring changes in the resonance frequency Delta fo, for the same mode of resonance, in response to different specimens of said substance having individual values of K1, K2 ---Kn.
Claim 3
Dependent Claim
16 words
Apparatus as defined in claim 1 wherein said microwave signal is derived from a microwave generator.
Claim 4
Dependent Claim
22 words
Apparatus as defined in claim 2 wherein the frequency of said generator is varied in response to a sweep generator connected thereto.
Claim 5
Dependent Claim
22 words
Apparatus as defined in claim 3 wherein said means for measuring changes in the resonant frequency Delta fo comprises a resonance discriminator.
Claim 6
Dependent Claim
16 words
Apparatus as defined in claim 4 further including output level indicator means connected to said discriminator.
Claim 7
Dependent Claim
19 words
Apparatus as defined in claim 1, wherein said detector head has only one side electrically open to said substance.
Claim 8
Dependent Claim
24 words
Apparatus as defined in claim 1, wherein said detector comprises a plurality of anodes disposed between end walls, said anodes being separated by gaps.
Claim 9
Dependent Claim
22 words
Apparatus as defined by claim 7, wherein said anodes define a plane, said substance being disposed substantially parallel to said anode plane.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |