Patent US5103103A successfully refreshed from Google Patents.
US5103103A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microwave shield
Assignee: Westinghouse Electric Corp
•
Filing: 1990-07-19
•
Granted: 1992-04-07
•
Expires: 2010-07-19
Abstract
Abstract A switchable shield which precludes transmission or receipt of radio frequency or microwave energy. The shield comprises a substrate of highly transmissive material with an active film layer disposed on the substrate. This active film layer is switchable upon heating from a high transmissivity, high resistivity mode which permits transmission or receipt of rf or microwave radiation, to a low transmissivity, low resistivity mode which precludes transmission or receipt of rf or microwave radiation through the shield.
Inventors
- 👤 Kenneth C. Radford
- 👤 Deborah P. Partlow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:36
CPC Classifications
G; G21; G21F; G21F1/00; H; H05; H05K; H05K9/00; H05K9/0073; H05K9/0081; H05K9/0084; H10; H10W; H10W42/00; H10W42/20
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
124 words
A switchable shield for an electromagnetic device which transmits or receives radio frequency or microwave radiation through said shield, which shield is selectively switchable form a first high transmissivity, high resistivity mode to a second low transmissivity, low resistivity mode, which shield comprises: a substrate formed of a material which is highly transmissive of radio frequency and microwave radiation; and an active film layer disposed on said substrate, which active film layer is switchable upon heating above a selected temperature from said first high transmissivity, high resistivity mode permitting transmission or receipt of radio frequency or microwave radiation by said electromagnetic device, to said second low transmissivity, low resistivity mode precluding transmission or receipt of radio frequency or microwave energy by said electromagnetic device.
Claim 2
Dependent Claim
124 words
A switchable shield for an electromagnetic device which transmits or receives radio frequency or microwave radiation through said shield, which shield is selectively switchable form a first high transmissivity, high resistivity mode to a second low transmissivity, low resistivity mode, which shield comprises: a substrate formed of a material which is highly transmissive of radio frequency and microwave radiation; and an active film layer disposed on said substrate, which active film layer is switchable upon heating above a selected temperature from said first high transmissivity, high resistivity mode permitting transmission or receipt of radio frequency or microwave radiation by said electromagnetic device, to said second low transmissivity, low resistivity mode precluding transmission or receipt of radio frequency or microwave energy by said electromagnetic device.
Claim 3
Dependent Claim
18 words
A switchable shield as described in claim 1, wherein the active film layer is comprised of vanadium oxide.
Claim 4
Dependent Claim
18 words
A switchable shield as described in claim 2, wherein the vanadium oxide consists essentially of VO 2 .
Claim 5
Dependent Claim
20 words
A switchable shield as described in claim 3, wherein the active film layer in the high transmissivity mode is semiconducting.
Claim 6
Dependent Claim
27 words
A switchable shield as described in claim 4, further characterized in that the active film layer in the high transmissivity, high resistivity mode has a monoclinic structure.
Claim 7
Dependent Claim
25 words
A switchable shield as described in claim 3, further characterized in that the active film layer in the low transmissivity, low resistivity mode is metallic.
Claim 8
Dependent Claim
27 words
A switchable shield as described in claim 6, further characterized in that the active film layer in the low transmissivity, low resistivity mode is tetragonal in structure.
Claim 9
Dependent Claim
18 words
A switchable shield as described in claim 2, further comprising a doping agent which alters the selected temperature.
Claim 10
Dependent Claim
29 words
A switchable shield as described in claim 8, wherein the doping agent is selected from the group consisting of chromium, molybdenum, titanium, manganese, nickel, iron, cobalt, tungsten and phosphorus.
Claim 11
Dependent Claim
15 words
A switchable shield as described in claim 1, wherein the active film layer is discontinuous.
Claim 12
Dependent Claim
25 words
A switchable shield as described in claim 1, wherein the active film layer has a thickness in the range of 100 Å to 10000 Å.
Claim 13
Dependent Claim
31 words
A switchable shield as described in claim 11, wherein the active film layer is further comprised of a plurality of film sublayers, each having a thickness of at least 100 Å.
Claim 14
Dependent Claim
31 words
A switchable shield as described in claim 11, wherein the active film layer is comprised of a single layer, having a thickness in the range of 2000 Å to 10000 Å.
Claim 15
Dependent Claim
24 words
A switchable shield as described in claim 13, wherein the single active film layer has a thickness of approximately 4000 Å to 8000 Å.
Claim 16
Dependent Claim
29 words
A switchable shield as described in claim 1, further characterized in that the active film layer changes from the first mode to the second mode at approximately 68° C.
Claim 17
Dependent Claim
35 words
A switchable shield as described in claim 15, wherein the active film layer is changed from the first mode to the second mode by heating with a forced air flow over the active film layer.
Claim 18
Dependent Claim
38 words
A switchable shield as described in claim 15, further characterized in that the active film layer is changed from the first mode to the second mode by passing an electric current therethrough to heat the active film layer.
Claim 19
Dependent Claim
27 words
A switchable shield as described in claim 1, wherein the active film layer changes from the first mode to the second mode over a narrow temperature range.
Claim 20
Dependent Claim
16 words
A switchable shield as described in claim 18, wherein the narrow temperature range is 3° C.
Claim 21
Dependent Claim
37 words
A switchable shield as described in claim 1, wherein the substrate layer is selected from the group consisting of glass, quartz, zirconia, corderite, polycrystalline aluminum oxide, aluminosilicates, aluminum nitride, boron nitride, silicon nitride, silicon carbide and sapphire.
Claim 22
Dependent Claim
21 words
A switchable shield as described in claim 20, wherein the alumino-silicates are selected from the group consisting of mullite and celsian.
Claim 23
Dependent Claim
37 words
A selectably shield as described in claim 1, wherein the substrate layer is selected from the group consisting of glass, quartz, zirconia, corderite, polycrystalline aluminum oxide, aluminosilicates, aluminum nitride, boron nitride, silicon nitride, silicon carbide and sapphire.
Claim 24
Dependent Claim
21 words
A switchable shield as described in claim 22, wherein the alumino-silicates are selected from the group consisting of mullite and celsian
Claim 25
Dependent Claim
47 words
A selectably intermittent shield as described in claim 1, wherein the substrate layer is formed from a material which is transparent to infrared electromagnetic radiation and is selected from the group consisting of silicon, germanium, calcium fluoride, barium fluoride, zinc sulfide, zinc selenide, diamond and gallium arsenide.
Claim 26
Dependent Claim
43 words
A switchable shield as described in claim 1, further characterized in that the resistivity of the active film layer decreases from approximately 10 6 Ω per square to approximately 1000 Ω per square when changed from the first mode to the second mode.
Claim 27
Dependent Claim
36 words
A switchable shield as described in claim 1, further characterized in that the transmissivity of the active film layer drops from approximately 90% to approximately 0% when changed from the first mode to the second mode.
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) | 1995-04-07 | 1995-10-07 | 1996-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-07 | 1999-10-07 | 2000-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-07 | 2003-10-07 | 2004-04-07 | $7700.00 | Window Closed / Lapsed |