US4312003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferrite antenna
Assignee: MSA Safety Inc
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Filing: 1980-09-15
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Granted: 1982-01-19
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Expires: 2000-09-15
Abstract
Abstract A ferrite antenna assembly comprising a ferrite rod surrounded by a first coil and positioned within a surrounding ferrite or the like cylinder provided with a second coil. A signal which is 180° out of phase with the signal on the first coil is applied to the second coil to induce a radio-frequency magnetic field in opposition to the field produced by the ferrite rod antenna. The opposing field creates a high reluctance return path for the magnetic flux emitted from the ferrite antenna at angles deviating from the axis of the rod. This forces the magnetic flux from the rod further out from the axis of the antenna, thus increasing the efficiency and range of the antenna.
Inventors
- 👤 Henry M. Robbins, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:00
CPC Classifications
H; H01; H01Q; H01Q7/00; H01Q7/06; H01Q7/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
86 words
In an antenna system, a first antenna coil connected to a signal source, a cylinder of magnetically-permeable material coaxial with and surrounding said first antenna coil, and a second coil for inducing magnetic flux in said cylinder and connected to a signal source which is 180° out of phase with respect to said first-mentioned signal source to thereby create a magnetic field in opposition to that produced by the antenna and force the magnetic flux from the antenna further away from the axis of the antenna.
Claim 2
Dependent Claim
86 words
In an antenna system, a first antenna coil connected to a signal source, a cylinder of magnetically-permeable material coaxial with and surrounding said first antenna coil, and a second coil for inducing magnetic flux in said cylinder and connected to a signal source which is 180° out of phase with respect to said first-mentioned signal source to thereby create a magnetic field in opposition to that produced by the antenna and force the magnetic flux from the antenna further away from the axis of the antenna.
Claim 3
Dependent Claim
17 words
The antenna system of claim 1 including a rod of magnetically-permeable material within said first antenna coil.
Claim 4
Dependent Claim
14 words
The antenna system of claim 2 wherein said rod is formed of ferrite material.
Claim 5
Dependent Claim
17 words
The antenna system of claim 1 wherein said cylinder of magnetically-permeable material is formed from ferrite material.
Claim 6
Dependent Claim
37 words
The antenna system of claim 1 wherein said signal source which is 180° out of phase with respect to said first-mentioned signal source comprises a phase shifter connected between the first-mentioned signal source and said second coil.
References Cited (Backward Citations)
US4148036A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-18 | 1985-07-20 | 1986-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-18 | 1989-07-20 | 1990-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-18 | 1993-07-20 | 1994-01-19 | $7700.00 | Window Closed / Lapsed |