US4785273A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Strip-line-core transformer
Assignee: Doty Scientific Inc
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Filing: 1987-06-30
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Granted: 1988-11-15
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Expires: 2007-06-30
Abstract
Abstract A broadband, high power rf transformer is made by winding a tapered strip-line transmission-line conductor and dielectric material through two parallel slots, formed axially and symmetrically spaced apart, through a solid right cylinder of low loss magnetic material. Low inductance strip lines are used as leads. A thin sheet of high thermal conductivity material may be added in such a way as to augment heat flow with negligible degradation of rf properties. The design is particularly advantageous at frequencies from 1 MHz to 1000 MHz at pulse powers to several kilowatts at impedances from 2Ω to 75Ω.
Inventors
- 👤 David F. Doty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:34
CPC Classifications
H; H01; H01F; H01F19/00; H01F19/04; H01F19/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
150 words
A wideband r.f. transformer comprising: a strip line core (SLC) made essentially from a carbonyl iron powder composite material, said core being defined by two substantially parallel plane surfaces and having two symmetrically spaced apart slots extending between said surfaces and substantially centered thereon; said slots being spaced apart less than 2 cm and positioned so as to form opposite sides of a substantially void free coil-core-region of substantially square cross section in a plane parallel to said plane surfaces; and a spiral winding of a strip line, consisting of conductor foil and spacer dielectric, threaded through said slots and round said coil-core-region; said slots being positioned on said surfaces so that the cross sectional area presented to magnetic flux generated by said spiral winding by the coil-core-region is less than 80% of the mean total cross sectional area presented to the flux by the material outside of said coil-core-region.
Claim 2
Dependent Claim
150 words
A wideband r.f. transformer comprising: a strip line core (SLC) made essentially from a carbonyl iron powder composite material, said core being defined by two substantially parallel plane surfaces and having two symmetrically spaced apart slots extending between said surfaces and substantially centered thereon; said slots being spaced apart less than 2 cm and positioned so as to form opposite sides of a substantially void free coil-core-region of substantially square cross section in a plane parallel to said plane surfaces; and a spiral winding of a strip line, consisting of conductor foil and spacer dielectric, threaded through said slots and round said coil-core-region; said slots being positioned on said surfaces so that the cross sectional area presented to magnetic flux generated by said spiral winding by the coil-core-region is less than 80% of the mean total cross sectional area presented to the flux by the material outside of said coil-core-region.
Claim 3
Dependent Claim
39 words
A wideband r.f. transformer in claim 1, in which said SLC is in the form of a right cylinder of height approximately equal to the spacing between said slots and approximately equal to one-third the diameter of said cylinder.
Claim 4
Dependent Claim
38 words
A wideband r.f. transformer as in claim 1, in which said iron powder composite material is an insulated soft carbonyl under about 9 microns average size, pressed to a packing fraction of at least 0.75 with rigid binders.
Claim 5
Dependent Claim
48 words
A wideband r.f. transformer as in claim 1, in which the inner edges of said slots are radiused so as to form a core-coil-region with a somewhat circular or elliptical cross section in a plane perpendicular to said plane surfaces and to the opposite sides of said core-coil-region.
Claim 6
Dependent Claim
30 words
A wideband r.f. transformer as in claim 1, in which a thin sheet of high conductivity material bisects said core along a plane of symmetry for said slots parallel thereto.
Claim 7
Dependent Claim
26 words
A wideband r.f. transformer as in claim 1, in which low loss dielectric material is provided between said strip line and said iron powder composite material.
Claim 8
Dependent Claim
29 words
A wideband r.f. transformer as in claim 1, in which low impedance taps made of conductive foil in the shape of a U are provided for said spiral winding.
Claim 9
Dependent Claim
37 words
A wideband r.f. transformer as in claim 1, in which dielectric material is interposed between turns at one end of said winding to impart a higher characteristic impedance at said one end than at the other end.
References Cited (Backward Citations)
US2883604A
Cited
US3025480A
Cited
US3020415A
Cited
US3050634A
Cited
DE1145280B
Cited
US3195076A
Cited
DE1257907B
Cited
US3464042A
Cited
US3766499A
Cited
US3783415A
Cited
US3826967A
Cited
JPH1188A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-15 | 1992-05-16 | 1992-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-15 | 1996-05-16 | 1996-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-15 | 2000-05-16 | 2000-11-15 | $7700.00 | Window Closed / Lapsed |