US2531447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hybrid channel-branching microwave filter
Assignee: AT&T Inc
•
Filing: 1947-12-05
•
Granted: 1950-11-28
•
Expires: 1967-12-05
Abstract
No abstract record available.
Inventors
- 👤 Willard D Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:46
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/207; H01P1/209; H01P1/213; H01P1/2138; H01P7/00; H01P7/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2194543A
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US2416790A
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US2438913A
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US2401751A
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US2408033A
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US2410838A
Cited
US2432093A
Cited
US2434646A
Cited
US2445895A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-11-27 | 1954-05-29 | 1954-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-11-27 | 1958-05-29 | 1958-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-11-27 | 1962-05-29 | 1962-11-28 | $7700.00 | Window Closed / Lapsed |