US3671888A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wide band stop band filter including a ferrite region biased by a graded magnetic field
Assignee: HP Inc
•
Filing: 1970-12-07
•
Granted: 1972-06-20
•
Expires: 1990-12-07
Abstract
Abstract A stripline conductor is sandwiched between two ferrite slabs which, in turn, are sandwiched between two magnetic pole pieces. The pole pieces are in contact with opposite poles of a permanent magnet, placing the ferrite slabs in a magnetic field. The distance between the pole pieces varies along the length of the stripline, causing the magnetic field to be nonuniform. The ferrite slabs will absorb electromagnetic radiation at a frequency determined by the magnetic field strength and thus signals on the stripline will be absorbed in a frequency band determined by the range of magnetic field strengths along the length of the stripline.
Inventors
- 👤 Pedro A Szente
- 👤 Robert Joly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:40
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/215
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
103 words
A band stop filter comprising: a transmission line having a first and a second conductor electrically insulated from one another for propagating electromagnetic waves; a piece of ferrite substantially filling the space between the first and second conductors of the transmission line in a region having a magnetic field component of an electromagnetic wave propagating along the transmission line; and magnetic means for producing a magnetic field varying along the direction of propagation of the electromagnetic wave on the transmission line and having a component normal to said magnetic field component of the electromagnetic wave, in the region containing the piece of ferrite.
Claim 2
Dependent Claim
103 words
A band stop filter comprising: a transmission line having a first and a second conductor electrically insulated from one another for propagating electromagnetic waves; a piece of ferrite substantially filling the space between the first and second conductors of the transmission line in a region having a magnetic field component of an electromagnetic wave propagating along the transmission line; and magnetic means for producing a magnetic field varying along the direction of propagation of the electromagnetic wave on the transmission line and having a component normal to said magnetic field component of the electromagnetic wave, in the region containing the piece of ferrite.
Claim 3
Dependent Claim
68 words
A band stop filter as in claim 1 wherein the first conductor is a flat stripline having a first ferrite slab in contact with one side and a second ferrite slab in contact with the other side thereof and the second conductor is supported in part by a surface of the first ferrite slab opposite the stripline and a surface of the second ferrite slab opposite the stripline.
Claim 4
Dependent Claim
92 words
A band stop filter as in claim 2 wherein the magnetic means comprises a magnet and first and second magnetic pole pieces, the first magnetic pole piece being adjacent the surface of the first ferrite slab opposite the stripline and connected to a first pole of the magnet, the second magnetic pole piece being adjacent the surface of the second ferrite slab opposite the stripline and connected to a second pole of the magnet, and the separation of the first and second magnetic pole pieces varying along the length of the striplIne.
Claim 5
Dependent Claim
81 words
A band stop filter as in claim 3 including magnetic circuit means wherein the magnetic means is symmetrical about the first conductor; the first magnetic pole piece being in contact with the conductor on the surface of the first ferrite slab opposite the stripline and; the second magnetic pole piece being in contact with the conductor on the surface of the second ferrite slab opposite the stripline and connected to the second pole of the magnet via the magnetic circuit means.
Claim 6
Dependent Claim
26 words
A band stop filter as in claim 4 wherein the separation of the first and second magnetic pole pieces varies monotonically with distance along the stripline.
Claim 7
Dependent Claim
48 words
A band stop filter as in claim 4 wherein the separation of the first and second magnetic pole pieces is substantially the same at each extreme of the stripline and increases to a greater, maximum value at a point approximately half way between the extremes of the stripline.
Claim 8
Dependent Claim
43 words
A band stop filter as in claim 5 wherein each magnetic pole piece has a notch in an end having the greatest thickness and nearest a ferrite slab for reducing fringing magnetic fields at the end of greatest separation between the pole pieces.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |