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US5617095A
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Hybrid type wide band electromagnetic wave absorber
Assignee: Korea Research Institute of Standards and Science
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Filing: 1995-10-18
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Granted: 1997-04-01
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Expires: 2015-10-18
Abstract
Abstract A hybrid-type wide band electromagnetic wave absorber having cone-shaped projections of a reduced may be produced by matching the impedance of the cone-shaped absorber members and the underlying plate type absorber. Such a hybrid-type wide band electromagnetic wave absorber is formed by arranging tapered cone-shaped members in a regular pattern on a sintered ferrite plate, which is disposed on a metal plate. The cone-shaped members are formed of a material selected from a ferrite and a ferrite composite and each have a normalized cross-sectional area at the base of 0<S 0 <1 and an exponent of cone shape of 0<n<10. Such a hybrid type electromagnetic wave absorber may be used, for example, for performing EMI/EMS testing in an anechoic chamber in the frequency range of 30 MHz to 1 GHz. In the case of applications such as antenna testing in the frequency range of 30 MHz to 30 GHz, the height of the cone-shaped members must be appropriately increased.
Inventors
- 👤 Dong-young Kim
- 👤 Yeon-Choon Chung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:27
CPC Classifications
H; H01; H01Q; H01Q17/00; H01Q17/008
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
49 words
A hybrid type wide band electromagnetic wave absorber comprising: a metal plate; a sintered ferrite plate disposed on the metal plate; and a plurality of spaced apart tapered cone members formed of a ferrite or ferrite composite material arranged in a regular square form on the sintered ferrite plate.
Claim 2
Dependent Claim
49 words
A hybrid type wide band electromagnetic wave absorber comprising: a metal plate; a sintered ferrite plate disposed on the metal plate; and a plurality of spaced apart tapered cone members formed of a ferrite or ferrite composite material arranged in a regular square form on the sintered ferrite plate.
Claim 3
Dependent Claim
64 words
A hybrid type wide band electromagnetic wave absorber according to claim 1; wherein the tapered cone members each have a normalized cross section at a bottom thereof within the range of 0<S 0 <1, wherein S 0 =a 2 /P 2 , "a" denotes the length of an edge at the bottom of a respective member and "P" denotes a pitch between adjacent members.
Claim 4
Dependent Claim
29 words
A hybrid type wide band electromagnetic wave absorber according to claim 1; wherein the tapered cone members each have an exponent of cone shape within the range of 0≦n≦10.
Claim 5
Dependent Claim
62 words
An electromagnetic wave absorber comprising: a metal plate; a ferrite-containing planar member disposed on the metal plate; and at least one ferrite-containing tapered member disposed on the ferrite-containing planar member; wherein the impedance of the ferrite-containing tapered member is matched to the impedance of the ferrite-containing planar member to permit a reduction in height of the tapered member over an expanded bandwidth.
Claim 6
Dependent Claim
62 words
An electromagnetic wave absorber comprising: a metal plate; a ferrite-containing planar member disposed on the metal plate; and at least one ferrite-containing tapered member disposed on the ferrite-containing planar member; wherein the impedance of the ferrite-containing tapered member is matched to the impedance of the ferrite-containing planar member to permit a reduction in height of the tapered member over an expanded bandwidth.
Claim 7
Dependent Claim
18 words
An electromagnetic wave absorber according to claim 4; wherein the ferrite-containing planar member comprises a sintered ferrite plate.
Claim 8
Dependent Claim
26 words
An electromagnetic wave absorber according to claim 4; wherein the ferrite-containing tapered member comprises a pyramid-shaped absorber formed of a ferrite or a ferrite composite material.
Claim 9
Dependent Claim
27 words
An electromagnetic wave absorber according to claim 4; wherein the at least one ferrite-containing tapered member comprises a plurality of members each spaced apart from each other.
Claim 10
Dependent Claim
38 words
An electromagnetic wave absorber according to claim 7; wherein the respective tapered members each have a normalized cross-sectional area at an interface between the planar member and the respective tapered member within the range of zero to one.
Claim 11
Dependent Claim
24 words
An electromagnetic wave absorber according to claim 7; wherein the respective tapered members each have an exponent of cone shape between zero and ten.
Claim 12
Dependent Claim
41 words
An electromagnetic wave absorber according to claim 4; wherein the at least one tapered member has a normalized cross-sectional area at an interface between the planar member and the at least one tapered member within the range of zero to one.
Claim 13
Dependent Claim
109 words
An electromagnetic wave absorber comprising: a metal plate; a sintered ferrite plate disposed on the metal plate; and a plurality of pyramid-shaped members disposed in a predetermined pattern on the sintered ferrite plate, each pyramid-shaped member being formed of a material selected from a ferrite or a ferrite composite and having a normalized cross-sectional area at a base thereof within the range of zero and 1, such that the impedance of the sintered ferrite plate may be matched to the impedance of the pyramid-shaped members and the height of the respective pyramid-shaped members may be reduced below 100 cm in the frequency range of 30 MHz to 1 GHz.
Claim 14
Dependent Claim
109 words
An electromagnetic wave absorber comprising: a metal plate; a sintered ferrite plate disposed on the metal plate; and a plurality of pyramid-shaped members disposed in a predetermined pattern on the sintered ferrite plate, each pyramid-shaped member being formed of a material selected from a ferrite or a ferrite composite and having a normalized cross-sectional area at a base thereof within the range of zero and 1, such that the impedance of the sintered ferrite plate may be matched to the impedance of the pyramid-shaped members and the height of the respective pyramid-shaped members may be reduced below 100 cm in the frequency range of 30 MHz to 1 GHz.
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) | 2000-03-31 | 2000-09-30 | 2001-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-31 | 2004-09-30 | 2005-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-31 | 2008-09-30 | 2009-04-01 | $7700.00 | Window Closed / Lapsed |