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US3739302A
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Miniaturized ferrimagnetic circulator for microwaves
Assignee: Smiths Interconnect Inc
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Filing: 1971-06-01
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Granted: 1973-06-12
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Expires: 1991-06-01
Abstract
Abstract A compact strip line type microwave circulator having an internal line impedance matching means is formed by a central conductor plate with spirally slotted conductor arms connected to suitable input and output ports, wherein the length of the slots bears a direct relation to a fractional wavelength of the microwave energy to be circulated and to the impedance of the input and output lines to be matched. The spiral cut central conductor plate is sandwiched between a pair of ferrite circulator elements, the opposite faces of the ferrite elements are bounded by parallel conductive ground planes, a pair of fixed magnets are positioned in intimate contact with the opposite ground plane conductors, and the entire assembly is enclosed within a steel housing containing a spring steel wafer to maintain pressure contact between abutting parallel surfaces of all elements in the sandwiched structure. In one embodiment a high loss ferrite attenuator is included within the sandwich assembly, coupled to a terminator port arm, and biased into resonance by the circulator fixed magnets to provide fail-safe internal termination - all within a unitary structure of only approximately 3/4 X 3/4 X 1/2 inch external dimensions in the 1.5 G HZ to 3.0 GHZ range. In another embodiment a circulator was developed at 975 MHZ in a 0.7 X 0.7 X 0.2 inch size.
Inventors
- 👤 Manus J Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:35
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/32; H01P1/38; H01P1/383; H01P1/387
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
138 words
In a microwave circulator having a high Mu ferrite element with opposed parallel plane surfaces, a metallic ground plane conductor plate in intimate contact with one plane surface of said ferrite element and a generally circular center conductor plate in intimate contact with the opposite plane surface of said ferrite element, the combination wherein said center conductor plate is formed with a plurality of peripheral arms extending spirally from within said generally circular conductor plate, said arms extending generally non-radially from said center conductor plate beyond the mean diameter thereof in contiguous overlying engagement with extending portions of said high Mu ferrite element means connecting the extremities of at least two of said arms with external electrical terminals, and a permanent magnet in intimate contact with the surface of said ground plane conductor plate opposite said ferrite element.
Claim 2
Dependent Claim
138 words
In a microwave circulator having a high Mu ferrite element with opposed parallel plane surfaces, a metallic ground plane conductor plate in intimate contact with one plane surface of said ferrite element and a generally circular center conductor plate in intimate contact with the opposite plane surface of said ferrite element, the combination wherein said center conductor plate is formed with a plurality of peripheral arms extending spirally from within said generally circular conductor plate, said arms extending generally non-radially from said center conductor plate beyond the mean diameter thereof in contiguous overlying engagement with extending portions of said high Mu ferrite element means connecting the extremities of at least two of said arms with external electrical terminals, and a permanent magnet in intimate contact with the surface of said ground plane conductor plate opposite said ferrite element.
Claim 3
Dependent Claim
44 words
The combination of claim 1 including a high loss ferrite element within the field of said permanent magnet and having opposed parallel plane surfaces in intimate contact with said ground plane plate and a peripheral end extension of one of said spiral conductor arms.
Claim 4
Dependent Claim
87 words
The combination of claim 1 characterized by a doubledeck sandwich configuration wherein said center conductor plaet is bounded on opposite faces thereof by a pair of high Mu ferrite elements, the opposite parallel plane surfaces of both said ferrite elements are in intimate contact with separate ground plane plates, and a pair of permanent magnets form the top and bottom of the sandwich structure, each of said magnets having a plane surface in intimate contact with the surfaces of said ground plane plates opposite said ferrite elements.
Claim 5
Dependent Claim
87 words
The combination of claim 1 wherein the mean diameter of said generally circular conductor plate approximately equals one half the wavelength of microwave energy to be circulated, and said spirally extending peripheral arms are formed between spiral slots extending into said center conductor plate within the mean diameter thereof, whereby the coupling between each of said spiral arms and said ground plane conductor through said ferrite dielectric forms a transmformer to match the low impedance of said ferrite circulator element to a higher impedance external transmission line.
Claim 6
Dependent Claim
190 words
In a microwave circulator having a pair of high Mu ferrite elements adjacent and overlying opposite plane surfaces of a substantially circular central conductor plate, the mean diameter of said central conductor plate being approximately equal to one half the wavelength of microwave energy to be circulated, and means for establishing a magnetic field substantially orthogonal to the planes of said ferrite elements and said conductor plate, the combination comprising, means defining a plurality of slots formed in said central conductor plate extending from the periphery thereof spirally inward toward the center thereof, a corresponding plurality of conductive arms remaining between said slots within said mean diameter, said arms extending generally non-radially from said central conductor plate beyond the mean diameter thereof in contiguous overlying engagement with extending portions of said high Mu ferrite elements, means connecting the extremities of two of said conductive arms to external electrical terminals, and a pair of lossy ferrite elements adjacent opposite surfaces of an extension of a third arm and located within said magnetic field whereby said lossy ferrite elements are biased to resonance at the frequency of microwave energy to be circulated.
Claim 7
Dependent Claim
190 words
In a microwave circulator having a pair of high Mu ferrite elements adjacent and overlying opposite plane surfaces of a substantially circular central conductor plate, the mean diameter of said central conductor plate being approximately equal to one half the wavelength of microwave energy to be circulated, and means for establishing a magnetic field substantially orthogonal to the planes of said ferrite elements and said conductor plate, the combination comprising, means defining a plurality of slots formed in said central conductor plate extending from the periphery thereof spirally inward toward the center thereof, a corresponding plurality of conductive arms remaining between said slots within said mean diameter, said arms extending generally non-radially from said central conductor plate beyond the mean diameter thereof in contiguous overlying engagement with extending portions of said high Mu ferrite elements, means connecting the extremities of two of said conductive arms to external electrical terminals, and a pair of lossy ferrite elements adjacent opposite surfaces of an extension of a third arm and located within said magnetic field whereby said lossy ferrite elements are biased to resonance at the frequency of microwave energy to be circulated.
Claim 8
Dependent Claim
52 words
The combination of claim 5 characterized by a central aperture formed in said center conductor plate, the diameter of said aperture being approximately one tenth the mean diameter of said center conductor plate, whereby the optimum frequency for operation of said circulator is reduced below the optimum frequency tHereof without said aperture.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |