US3629761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Broadband high-frequency transformer
Assignee: Motorola Solutions Inc
•
Filing: 1970-05-01
•
Granted: 1971-12-21
•
Expires: 1990-05-01
Abstract
Abstract Transformer for use in the 25- to 50-megahertz frequency band for coupling from a 50-ohm source impedance to the low-input impedance of a transistor power amplifier. The transformer includes a single-layer primary winding on a ferrite rod core, with a wide-strip secondary winding about the primary winding. The primary winding may have 15 turns and the secondary winding two turns, with the secondary winding covering substantially the entire outer surface of the primary winding. The frequency of self-resonance of the transformer is above 50 megahertz so that the transformer can be used over a complete octave of frequencies (25 to 50 megahertz). The windings and terminations have lowleakage inductance to hold the LC ratio low for broadband operation.
Inventors
- 👤 Kenneth P Lundgren
- 👤 Rolf E Kowalewski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:02
CPC Classifications
H; H01; H01F; H01F19/00; H01F19/04; H01F19/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
113 words
A broadband, high-frequency transformer including in combination, an elongated ferrite rod core, a first winding having a plurality of turns spaced from each other and wound in a single layer on said core, an insulating layer about said first winding, a second winding formed by a flat conductive strip wound about said insulating layer, said second winding having substantially less turns than said first winding and covering a large portion of the area of said first winding, and adhesive means securing said first winding to said core and securing said first and second windings to said insulating layer, said windings having integral extensions for making electrical connections thereto and for supporting the transformer.
Claim 2
Dependent Claim
113 words
A broadband, high-frequency transformer including in combination, an elongated ferrite rod core, a first winding having a plurality of turns spaced from each other and wound in a single layer on said core, an insulating layer about said first winding, a second winding formed by a flat conductive strip wound about said insulating layer, said second winding having substantially less turns than said first winding and covering a large portion of the area of said first winding, and adhesive means securing said first winding to said core and securing said first and second windings to said insulating layer, said windings having integral extensions for making electrical connections thereto and for supporting the transformer.
Claim 3
Dependent Claim
52 words
A transformer in accordance with claim 1 wherein said core has a length of the order of 1 inch, said first winding is the transformer primary winding and said second winding is the transformer secondary winding, and said primary winding has at least five times as many turns as said secondary winding.
Claim 4
Dependent Claim
62 words
A transformer in accordance with claim 1 for use in the frequency range from 25 to 50 megahertz wherein said first winding is the transformer primary winding and has about 15 turns and said second winding is the transformer secondary winding and has about two turns, and said transformer has an impedance ratio of the order of 50 ohms to 1 ohm.
Claim 5
Dependent Claim
34 words
A transformer in accordance with claim 3 wherein the turns of said first winding are so spaced, and said windings are so constructed that the self-resonant frequency of the transformer is above 50 megahertz.
Claim 6
Dependent Claim
29 words
A transformer in accordance with claim 1 wherein said second winding is the primary winding of the transformer and said first winding is the secondary winding of the transformer.
Claim 7
Dependent Claim
39 words
A transformer in accordance with claim 5 wherein said secondary winding has at least five times as many turns as said primary winding, and said transformer has an impedance ratio of the order of 1 ohm to 50 ohms.
References Cited (Backward Citations)
US1722444A
Cited
US2570762A
Cited
US2809357A
Cited
US2837725A
Cited
US2860312A
Cited
US2963669A
Cited
US3079526A
Cited
US3169234A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |