US2840820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Artificial medium of variable dielectric constant
Assignee: AT&T Inc
•
Filing: 1954-04-14
•
Granted: 1958-06-24
•
Expires: 1974-04-14
Abstract
No abstract record available.
Inventors
- 👤 George C Southworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:29
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/44
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2129712A
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US2607849A
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US2652493A
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US2644926A
Cited
US2685065A
Cited
US2668191A
Cited
US2669657A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-06-23 | 1961-12-23 | 1962-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-06-23 | 1965-12-23 | 1966-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-06-23 | 1969-12-23 | 1970-06-24 | $7700.00 | Window Closed / Lapsed |