US3889213A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double-cavity microwave filter
Assignee: United States Department of the Navy
•
Filing: 1974-04-25
•
Granted: 1975-06-10
•
Expires: 1994-04-25
Abstract
Abstract An improved magnetically tunable band-pass filter for use in the microwave regions, particularly at X-band and beyond. Two waveguides are adjacently positioned to form a double cavity arrangement such that the radio-frequency (RF) magnetic fields in each cavity are orthogonal to one another. A substrate, having thin-film layers of ferrimagnetic material deposited on opposed parallel surfaces, is positioned in an opening between the adjacent cavities so that one of the layers is positioned in each cavity to form a coupling resonator. An external direct current (DC) magnetic bias field is then applied in a direction normal to the input RF field and controlled in angle relative to the surface of the ferrimagnetic material. For any given magnitude of the magnetic bias field, the resonance and, thus, the bandpass of the filter, is adjusted over a wide range of frequency by varying the angle of the magnetic bias field relative to the noted surface.
Inventors
- 👤 Carmine Vittoria
- 👤 Joseph Pasternak
- 👤 Howard Lessoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:28
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/215; H01P1/218
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
114 words
A magnetically tunable band-pass filter comprising: a first microwave input portion for receiving microwave energy; a second microwave output portion for transmitting microwave energy, said first and second portions being mounted adjacent to one another and connected by an opening therebetween; a ferrimagnetic resonator positioned in said opening and comprising a substrate having opposed parallel surfaces with a ferrimagnetic material deposited uniformly over said opposed surfaces, said resonator being positioned such that one of said surfaces extends into said input portion and the other into the output portion; and magnetic means for applying a magnetic field to said resonator and varying the angle of the field relative to the surface of said ferrimagnetic material.
Claim 2
Dependent Claim
114 words
A magnetically tunable band-pass filter comprising: a first microwave input portion for receiving microwave energy; a second microwave output portion for transmitting microwave energy, said first and second portions being mounted adjacent to one another and connected by an opening therebetween; a ferrimagnetic resonator positioned in said opening and comprising a substrate having opposed parallel surfaces with a ferrimagnetic material deposited uniformly over said opposed surfaces, said resonator being positioned such that one of said surfaces extends into said input portion and the other into the output portion; and magnetic means for applying a magnetic field to said resonator and varying the angle of the field relative to the surface of said ferrimagnetic material.
Claim 3
Dependent Claim
33 words
The apparatus of claim 1 wherein said input and output portions are formed from a pair of shorted end waveguides mounted in adjacent overlapping relationship having a connecting passage as said opening therebetween.
Claim 4
Dependent Claim
38 words
The apparatus of claim 2 wherein the waveguides are oriented such that the radio frequency magnetic field components in the input and output waveguides are orthogonal to one another to prevent direct coupling of energy through the passage.
Claim 5
Dependent Claim
18 words
The apparatus of claim 1 wherein the substrate is formed from gadolinium-gallium-garnet and the ferrimagnetic material from yttrium-iron-garnet.
Claim 6
Dependent Claim
40 words
The apparatus of claim 1 wherein the resonator is so positioned in said opening that the surface of the ferrimagnetic material in the input portion is substantially parallel to the direction of the magnetic field component of raDio frequency energy.
Claim 7
Dependent Claim
37 words
The apparatus of claim 5 wherein the means for applying said magnetic field applies a DC field in a direction normal to the direction of the magnetic field component of radio frequency energy in the input portion.
Claim 8
Dependent Claim
35 words
The apparatus of claim 6 wherein the means for varying the DC magnetic field varies the DC field over an angle of at least 0* to 90* relative to the surface of the ferrimagnetic material.
Claim 9
Dependent Claim
28 words
The apparatus of claim 1 further including a means positioned adjacent the surface of said ferrimagnetic material in the output portion for increasing the coupling through said resonator.
Claim 10
Dependent Claim
25 words
The apparatus of claim 8 wherein said means comprises a coupling screw adjustably mounted along an axis normal to the surface of said ferrimagnetic material.
Claim 11
Dependent Claim
15 words
The apparatus of claim 1 wherein the ferrimagnetic material has an aspect ratio of 100-1000.
Claim 12
Dependent Claim
101 words
A magnetically tunable band-pass filter comprising: a first microwave input portion for receiving microwave energy; a second microwave output portion for transmitting microwave energy, said first and second portions being mounted adjacent to one another and connected by an opening therebetween; a ferrimagnetic resonator positioned in said opening and comprising a substrate having opposed parallel surfaces with a ferrimagnetic material deposited uniformly over said opposed surfaces, said resonator being positioned such that one of said surfaces extends into said input portion and the other into the output portion; and magnetic means for applying a variable magnitude magnetic field to said resonator.
Claim 13
Dependent Claim
101 words
A magnetically tunable band-pass filter comprising: a first microwave input portion for receiving microwave energy; a second microwave output portion for transmitting microwave energy, said first and second portions being mounted adjacent to one another and connected by an opening therebetween; a ferrimagnetic resonator positioned in said opening and comprising a substrate having opposed parallel surfaces with a ferrimagnetic material deposited uniformly over said opposed surfaces, said resonator being positioned such that one of said surfaces extends into said input portion and the other into the output portion; and magnetic means for applying a variable magnitude magnetic field to said resonator.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |