US5325094A
Expired / Lapsed
US
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Electromagnetic energy absorbing structure
Assignee: Parker Intangibles LLC
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Filing: 1992-05-15
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Granted: 1994-06-28
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Expires: 2012-05-15
Abstract
Abstract An electromagnetic energy absorbing structure provides a base structure having an electrically conductive ground plane positioned thereover. At least one dielectric and one impedance layer are positioned over the ground plane or surface on a side thereof opposite the base. An external most dielectric skin seals the structure. Additional alternating dielectric and impedance layers can be positioned over the first dielectric and impedance layers. The dielectric layer can be constructed from syntactic foam with impedance layers formed from patterns of conductive dipoles. The impedance layer, can alternatively, be formed from a resistive sheet formed into a broken pattern that may comprise a series of geometric shapes spaced from each other. The resistive sheet can be combined with a series of composite dielectric layers to form an integral composite structure.
Inventors
- 👤 John F. Broderick
- 👤 Noel J. Tessier
- 👤 Michael S. Heafey
- 👤 Michael T. Kocsik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:34
CPC Classifications
H; H01; H01Q; H01Q15/00; H01Q15/0006; H01Q15/0013; H01Q15/0026; H01Q17/00
Claims Analysis
Total Claims: 121
Claim 1
Independent Claim
84 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; at least a first dielectric layer disposed over the ground surface; a first impedance layer, the impedance layer comprising a resistive material having a first predetermined broken pattern, and having an impedance in a range of approximately 200-400 ohms disposed over the first dielectric layer on a side thereof opposite the ground layer, and a skin dielectric layer disposed external-most from the base.
Claim 2
Dependent Claim
84 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; at least a first dielectric layer disposed over the ground surface; a first impedance layer, the impedance layer comprising a resistive material having a first predetermined broken pattern, and having an impedance in a range of approximately 200-400 ohms disposed over the first dielectric layer on a side thereof opposite the ground layer, and a skin dielectric layer disposed external-most from the base.
Claim 3
Dependent Claim
26 words
The structure of claim 1 further comprising a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer.
Claim 4
Dependent Claim
50 words
The structure of claim 2 further comprising a second impedance layer, the layer comprising a resistive material and having an impedance in a range of approximately 200-400 ohms and having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer.
Claim 5
Dependent Claim
26 words
The structure of claim 3 further comprising a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer.
Claim 6
Dependent Claim
31 words
The structure of claim 4 wherein each of the first and the second impedance layers and the first, the second and the third dielectric layers are all parallel to each other.
Claim 7
Dependent Claim
37 words
The structure of claim 4 wherein at least one of the first and the second impedance layers comprises a resistive layer having one of a corresponding first and second broken pattern formed in a resistive material sheet.
Claim 8
Dependent Claim
31 words
The structure of claim 6 wherein at least one of the first and the second broken pattern comprises a plurality of repeating adjacent geometric shapes each having a predetermined spacing therebetween.
Claim 9
Dependent Claim
27 words
The structure of claim 7 wherein each of the geometric shapes comprises a substantially identical square and the predetermined spacing between each adjacent square is substantially equal.
Claim 10
Dependent Claim
53 words
The structure of claim 8 wherein each of the first and the second impedance layers comprises a plurality of substantially identical squares of a resistive sheet each square spaced a predetermined distance from adjacent squares, the squares of the first impedance layer each being larger than the squares of the second impedance layer.
Claim 11
Dependent Claim
35 words
The structure of claim 1 wherein the first impedance layer comprises a resistive layer formed from a resistive sheet having a plurality of adjacent discrete geometrical shapes thereon spaced a predetermined distance from each other.
Claim 12
Dependent Claim
30 words
The structure of claim 10 wherein each of the geometrical shapes comprises a substantially identical square and the predetermined distance of spacing for each of adjacent squares is substantially equal.
Claim 13
Dependent Claim
19 words
The structure of claim 1 wherein the first impedance layer comprises a polymer having a lossy material contained therein.
Claim 14
Dependent Claim
10 words
The structure of claim 12 wherein the polymer comprises polyimide.
Claim 15
Dependent Claim
12 words
The structure of claim 13 wherein the lossy material comprises carbon black.
Claim 16
Dependent Claim
179 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed on the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer, wherein each of the first and the second impedance layers and the first, wherein the second and the third dielectric layers are all parallel to each other and wherein at least one of the second and third dielectric layers comprise a syntactic foam; and a skin dielectric layer disposed external-most from the base.
Claim 17
Dependent Claim
179 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed on the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer, wherein each of the first and the second impedance layers and the first, wherein the second and the third dielectric layers are all parallel to each other and wherein at least one of the second and third dielectric layers comprise a syntactic foam; and a skin dielectric layer disposed external-most from the base.
Claim 18
Dependent Claim
35 words
The structure of claim 15 wherein at least one of the first and the second impedance layers comprises a conductive layer having a corresponding first and second broken pattern of dipoles formed from conductive ink.
Claim 19
Dependent Claim
29 words
The structure of claim 16 wherein the conductive ink includes a polyester binder and is positioned directly upon at least one of the second and the third dielectric layers.
Claim 20
Dependent Claim
180 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer; and a skin dielectric layer disposed external-most from the base wherein the third dielectric layer includes the external-most skin layer comprising a fiberglass reinforced epoxy composite layer and the third dielectric layer also includes an internal most syntactic foam layer proximate the second impedance layer.
Claim 21
Dependent Claim
180 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer; and a skin dielectric layer disposed external-most from the base wherein the third dielectric layer includes the external-most skin layer comprising a fiberglass reinforced epoxy composite layer and the third dielectric layer also includes an internal most syntactic foam layer proximate the second impedance layer.
Claim 22
Dependent Claim
97 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer, wherein the first impedance layer comprises a conductive layer and the first predetermined broken pattern comprises a series of varying length dipoles arranged in each of a first and a second perpendicular direction; and a skin dielectric layer disposed external-most from the base.
Claim 23
Dependent Claim
97 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer, wherein the first impedance layer comprises a conductive layer and the first predetermined broken pattern comprises a series of varying length dipoles arranged in each of a first and a second perpendicular direction; and a skin dielectric layer disposed external-most from the base.
Claim 24
Dependent Claim
38 words
The structure of claim 19 wherein the first predetermined broken pattern includes a plurality of adjacent squares of the series of varying length dipoles, the dipoles of each square being joined so as to form a continuous pattern.
Claim 25
Dependent Claim
61 words
The structure of claim 20 wherein the series of varying length dipoles in each square is rotated at least 90° relative to the respective series of varying length dipoles in each respective of adjacent squares thereto, the series of varying length dipoles being arranged so that predetermined of the dipoles in each of adjacent rotated squares forms a continuous semi-random pattern.
Claim 26
Dependent Claim
192 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer, wherein at least one of the first and the second impedance layers comprises a resistive layer having one of a corresponding first and second broken pattern formed in a resistive material sheet, wherein the resistive material sheet comprises a polymer sheet having a lossy material disposed therein; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer; and a skin dielectric layer disposed external-most from the base.
Claim 27
Dependent Claim
192 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer, wherein at least one of the first and the second impedance layers comprises a resistive layer having one of a corresponding first and second broken pattern formed in a resistive material sheet, wherein the resistive material sheet comprises a polymer sheet having a lossy material disposed therein; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer; and a skin dielectric layer disposed external-most from the base.
Claim 28
Dependent Claim
14 words
The structure of claim 22 wherein the resistive material sheet comprises a polyimide sheet.
Claim 29
Dependent Claim
24 words
The structure of claim 22 wherein each of the first, the second and the third dielectric layers comprises a fiberglass reinforced epoxy composite material.
Claim 30
Dependent Claim
34 words
The structure of claim 24 wherein the fiberglass reinforced epoxy composite material includes a plurality of layers of bidirectional and unidirectional glass cloth, each of the plurality of layers having a predetermined directional orientation.
Claim 31
Dependent Claim
250 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer, wherein at least one of the first and the second impedance layers comprises a resistive layer having one of a corresponding first and second broken pattern formed in a resistive material sheet, and wherein at least one of the first and the second broken pattern comprises a plurality of repeating adjacent substantially identical squares each having a predetermined space therebetween, wherein the predetermined space between each adjacent square is substantially equal and wherein each of the squares is joined to an adjacent square in the resistive sheet by a runner extending from adjacent edges of adjacent squares, the runners being substantially narrower than the edges; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer; and a skin dielectric layer disposed external-most from the base.
Claim 32
Dependent Claim
250 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; a second dielectric layer disposed over the first impedance layer on a side thereof opposite the first dielectric layer; a second impedance layer, being one of a resistive and a conductive layer having a second predetermined broken pattern, disposed over the second dielectric layer on a side thereof opposite the first impedance layer, wherein at least one of the first and the second impedance layers comprises a resistive layer having one of a corresponding first and second broken pattern formed in a resistive material sheet, and wherein at least one of the first and the second broken pattern comprises a plurality of repeating adjacent substantially identical squares each having a predetermined space therebetween, wherein the predetermined space between each adjacent square is substantially equal and wherein each of the squares is joined to an adjacent square in the resistive sheet by a runner extending from adjacent edges of adjacent squares, the runners being substantially narrower than the edges; a third dielectric layer disposed over the second impedance layer on a side thereof opposite the second dielectric layer; and a skin dielectric layer disposed external-most from the base.
Claim 33
Dependent Claim
99 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface, wherein the base comprises a structural member of an object and at least the first dielectric layer is formed of the same material as the base; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; and a skin dielectric layer disposed external-most from the base.
Claim 34
Dependent Claim
99 words
An electromagnetic energy absorbing structure comprising: a base including an electrically conductive ground surface disposed over a surface of the base; a first dielectric layer disposed over the ground surface, wherein the base comprises a structural member of an object and at least the first dielectric layer is formed of the same material as the base; a first impedance layer, being one of a resistive and a conductive layer having a first predetermined broken pattern, disposed over the first dielectric layer on a side thereof opposite the ground layer; and a skin dielectric layer disposed external-most from the base.
Claim 35
Dependent Claim
43 words
The structure of claim 27 wherein the base and the first dielectric layer each comprise a material reinforced matrix bonded composite material and wherein the matrix of each of the base and the dielectric layer is applied substantially simultaneously in a single step.
Claim 36
Dependent Claim
24 words
The structure of claim 28 wherein the electrically conductive ground surface comprises an expanded mesh screen of substantially pure copper disposed over the base.
Claim 37
Independent Claim
161 words
A method of forming electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer comprising a broken pattern resistive material having a lossy material therein, the first impedance layer being positioned over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, the ground layer, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 38
Independent Claim
161 words
A method of forming electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer comprising a broken pattern resistive material having a lossy material therein, the first impedance layer being positioned over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, the ground layer, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 39
Dependent Claim
33 words
The method of claim 30 wherein the step of positioning the first impedance layer includes applying a first resistive sheet having a plurality of substantially identical geometrical shapes over the first dielectric layer.
Claim 40
Dependent Claim
29 words
The method of claim 31 wherein the step of applying the first resistive sheet includes forming the substantially identical geometrical shapes into squares each having substantially equal spacing therebetween.
Claim 41
Dependent Claim
38 words
The method of claim 31 further comprising providing a second dielectric layer over the first impedance layer and further providing a second impedance layer of the second dielectric layer on a side thereof opposite the first impedance layer.
Claim 42
Dependent Claim
33 words
The method of claim 33 wherein the step of providing the second impedance layer includes applying a second resistive sheet having a plurality of substantially identical geometrical shapes over the second dielectric layer.
Claim 43
Dependent Claim
26 words
The method of claim 34 further comprising positioning a third dielectric layer over the second impedance layer on a side thereof opposite the second dielectric layer.
Claim 44
Dependent Claim
24 words
The method of claim 30 wherein the positioning of at least the first impedance layer includes providing an impedance layer that comprises a polymer.
Claim 45
Dependent Claim
23 words
The method of claim 30 wherein the positioning of at least the first impedance layer includes providing a resistive layer that comprises polyimide.
Claim 46
Dependent Claim
30 words
The method of claim 30 wherein the positioning of at least the first impedance layer includes providing a resistive material having an impedance in a range of approximately 100-500 ohms.
Claim 47
Dependent Claim
24 words
The method of claim 38 wherein the positioning of at least the first impedance layer further includes providing a resistive material having carbon black.
Claim 48
Dependent Claim
43 words
The method of claim 30 wherein the step of permanently securing includes injecting a hardenable liquid matrix to secure each of the base layer, the first dielectric layer, the first impedance layer and the dielectric skin layer together, forming a structural member therefrom.
Claim 49
Dependent Claim
41 words
The method of claim 40 wherein the step of permanently securing includes providing a cavity mold for receiving the structure and injecting a hardenable liquid matrix under pressure into the cavity mold and subsequently curing the matrix to harden the matrix.
Claim 50
Independent Claim
189 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer disposed over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being one of a broken pattern resistive layer and a conductive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, wherein the step of positioning at least the first impedance layer includes applying a conductive layer over the first dielectric layer, the step of applying including screen printing conductive ink in a predetermined pattern; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 51
Independent Claim
189 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer disposed over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being one of a broken pattern resistive layer and a conductive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, wherein the step of positioning at least the first impedance layer includes applying a conductive layer over the first dielectric layer, the step of applying including screen printing conductive ink in a predetermined pattern; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 52
Independent Claim
189 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being one of a broken pattern resistive layer and a conductive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, wherein the step of positioning at least the first impedance layer includes forming an impedance layer pattern having a plurality of varying length dipoles arranged in each of a first and a second perpendicular direction; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 53
Independent Claim
189 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being one of a broken pattern resistive layer and a conductive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, wherein the step of positioning at least the first impedance layer includes forming an impedance layer pattern having a plurality of varying length dipoles arranged in each of a first and a second perpendicular direction; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 54
Dependent Claim
54 words
The method of claim 43 further comprising the step of positioning a second dielectric layer over the first impedance layer on a side thereof opposite the first dielectric layer, the step of forming including placing the predetermined pattern on at least one of the first and the second dielectric layers at facing surfaces thereof.
Claim 55
Dependent Claim
23 words
The method of claim 44 wherein the step of positioning a second dielectric layer includes providing syntactic foam proximate the first impedance layer.
Claim 56
Dependent Claim
33 words
The method of claim 45 further comprising positioning a second impedance layer having a predetermined thickness, the second impedance layer being one of a conductive and resistive layer, over the second dielectric layer.
Claim 57
Dependent Claim
36 words
The method of claim 46 further comprising positioning a third dielectric layer having a predetermined thickness relative to the second impedance layer over the second impedance layer on a side thereof opposite the second dielectric layer.
Claim 58
Dependent Claim
23 words
The method of claim 47 wherein the step of positioning the third dielectric layer includes providing syntactic foam proximate the second impedance layer.
Claim 59
Dependent Claim
38 words
The method of claim 48 wherein the step of permanently securing includes at least one of applying adhesive between dielectric layers and injecting a hardenable liquid matrix between the base, the first dielectric layer and the skin layer.
Claim 60
Dependent Claim
38 words
The method of claim 46 wherein the step of positioning the second impedance layer includes applying conductive ink in a predetermined pattern to at least one of the second and the third dielectric layers along facing surfaces thereof.
Claim 61
Independent Claim
203 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being a broken pattern resistive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, and the step of positioning the first impedance layer further including applying a first resistive sheet having a plurality of substantially identical squares each having substantially equal spacing therebetween over the first dielectric layer, wherein the step of applying the first resistive sheet includes providing a sheet of polyimide material that includes a lossy material; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 62
Independent Claim
203 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being a broken pattern resistive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, and the step of positioning the first impedance layer further including applying a first resistive sheet having a plurality of substantially identical squares each having substantially equal spacing therebetween over the first dielectric layer, wherein the step of applying the first resistive sheet includes providing a sheet of polyimide material that includes a lossy material; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 63
Dependent Claim
24 words
The method of claim 51 wherein the step of providing a sheet of polyimide material includes providing a sheet of Du Pont XC™ material.
Claim 64
Independent Claim
241 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning a first impedance layer over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, the step of positioning the first impedance layer further including applying a first resistive sheet having a plurality of substantially identical geometrical shapes over the first dielectric layer; positioning a second dielectric layer over the first impedance layer over the second dielectric layer on a side thereof opposite the first impedance layer, the step of positioning the second impedance layer including applying a second resistive sheet having a plurality of substantially identical geometric shapes over the second dielectric layer, wherein the identical geometrical shapes of the first impedance layer are larger than the identical geometrical shapes of the second impedance layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing each of the base, the first dielectric layer, the first impedance layer the second dielectric layer, the second impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 65
Independent Claim
241 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning a first impedance layer over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, the step of positioning the first impedance layer further including applying a first resistive sheet having a plurality of substantially identical geometrical shapes over the first dielectric layer; positioning a second dielectric layer over the first impedance layer over the second dielectric layer on a side thereof opposite the first impedance layer, the step of positioning the second impedance layer including applying a second resistive sheet having a plurality of substantially identical geometric shapes over the second dielectric layer, wherein the identical geometrical shapes of the first impedance layer are larger than the identical geometrical shapes of the second impedance layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing each of the base, the first dielectric layer, the first impedance layer the second dielectric layer, the second impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 66
Independent Claim
284 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning a first impedance layer over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, the step of positioning the first impedance layer including applying a first resistive sheet having a plurality of substantially identical geometrical shapes over the first dielectric layer; positioning a second dielectric layer over the first impedance layer and further positioning a second impedance layer over the second dielectric layer on a side thereof opposite the first impedance layer, wherein the step of positioning the second impedance layer includes applying a second resistive sheet having a plurality of substantially identical geometrical shapes over the second dielectric layer; positioning a third dielectric layer over the second impedance layer on a side thereof opposite the second dielectric layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; wherein the step of providing the base layer and the steps of positioning each of the first, the second and the third dielectric layers include applying a predetermined number of layers of unidirectional and bidirectional material in predetermined orientations; and permanently securing each of the base, the first dielectric layer, the first impedance layer, the second dielectric layer, the third dielectric layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 67
Independent Claim
284 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning a first impedance layer over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer, the step of positioning the first impedance layer including applying a first resistive sheet having a plurality of substantially identical geometrical shapes over the first dielectric layer; positioning a second dielectric layer over the first impedance layer and further positioning a second impedance layer over the second dielectric layer on a side thereof opposite the first impedance layer, wherein the step of positioning the second impedance layer includes applying a second resistive sheet having a plurality of substantially identical geometrical shapes over the second dielectric layer; positioning a third dielectric layer over the second impedance layer on a side thereof opposite the second dielectric layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; wherein the step of providing the base layer and the steps of positioning each of the first, the second and the third dielectric layers include applying a predetermined number of layers of unidirectional and bidirectional material in predetermined orientations; and permanently securing each of the base, the first dielectric layer, the first impedance layer, the second dielectric layer, the third dielectric layer and the skin layer together so as to form an integral structural member having a predetermined shape.
Claim 68
Dependent Claim
31 words
The method of claim 54 wherein the step of permanently securing includes injecting a hardenable liquid matrix for adhering each of the layers of unidirectional and bidirectional material to one another.
Claim 69
Independent Claim
193 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being one of a broken pattern resistive layer and a conductive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, the ground layer, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape, wherein the step of permanently securing includes providing a cavity mold for receiving the structure and injecting a hardenable liquid matrix under pressure into the cavity mold and subsequently curing the matrix to harden the matrix.
Claim 70
Independent Claim
193 words
A method of forming an electromagnetic energy absorbing structure comprising the steps of: providing a base layer including an electrically conductive ground surface on the base layer; positioning at least a first dielectric layer over the ground surface, the first dielectric layer having a predetermined thickness relative to the ground surface; positioning at least a first impedance layer, the first impedance layer being one of a broken pattern resistive layer and a conductive layer, over the dielectric layer on a side thereof opposite the ground layer, the first impedance layer having a predetermined thickness relative to the first dielectric layer; positioning a dielectric skin layer at an external-most location relative to the base, the skin layer having a predetermined thickness; and permanently securing the base, the ground layer, at least the first dielectric layer, at least the first impedance layer and the skin layer together so as to form an integral structural member having a predetermined shape, wherein the step of permanently securing includes providing a cavity mold for receiving the structure and injecting a hardenable liquid matrix under pressure into the cavity mold and subsequently curing the matrix to harden the matrix.
Claim 71
Dependent Claim
43 words
The method of claim 56 wherein the at least one of the dielectric layers comprise fiberglass and wherein the matrix comprises an epoxy resin and wherein the step of curing includes exposing the epoxy resin to heat for a predetermined period of time.
Claim 72
Dependent Claim
117 words
An electromagnetic energy absorbing structure comprising; a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first conductive layer comprising a first dipole pattern positioned over the first dielectric layer; a second dielectric layer comprising syntactic foam positioned over the first conductive layer; a second conductive layer comprising a second dipole pattern positioned over the second dielectric layer; and an external-most dielectric skin layer, at least one of the first and the second dipole pattern comprising a plurality of varying length linear segments of conductive dipole material, at least some of the segments being interconnected with other of the segments.
Claim 73
Dependent Claim
117 words
An electromagnetic energy absorbing structure comprising; a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first conductive layer comprising a first dipole pattern positioned over the first dielectric layer; a second dielectric layer comprising syntactic foam positioned over the first conductive layer; a second conductive layer comprising a second dipole pattern positioned over the second dielectric layer; and an external-most dielectric skin layer, at least one of the first and the second dipole pattern comprising a plurality of varying length linear segments of conductive dipole material, at least some of the segments being interconnected with other of the segments.
Claim 74
Dependent Claim
41 words
The structure of claim 58 wherein predetermined groupings of dipole segments form a block having a predetermined pattern, at least one of the first conductive layer and the second conductive layer having a plurality of blocks comprising the predetermined pattern thereover.
Claim 75
Dependent Claim
35 words
The structure of claim 59 wherein at least some of the blocks are located adjacent each other, the pattern of at least some of the blocks being rotated relative to other adjacent of the blocks.
Claim 76
Dependent Claim
35 words
The structure of claim 60 wherein at least some of the blocks comprise squares and wherein the pattern of blocks are rotated in increments of 90° relative to a pattern and adjacent of the blocks.
Claim 77
Dependent Claim
107 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first conductive layer comprising a first dipole pattern positioned over the first dielectric layer; a second dielectric layer comprising a syntactic foam positioned over the first conductive layer; a second conductive layer comprising a second dipole pattern positioned over the second dielectric layer, wherein at least one of the first and the second conductive layers comprise conductive ink applied to one of the first and second dielectric layers; and an external-most dielectric skin layer.
Claim 78
Dependent Claim
107 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first conductive layer comprising a first dipole pattern positioned over the first dielectric layer; a second dielectric layer comprising a syntactic foam positioned over the first conductive layer; a second conductive layer comprising a second dipole pattern positioned over the second dielectric layer, wherein at least one of the first and the second conductive layers comprise conductive ink applied to one of the first and second dielectric layers; and an external-most dielectric skin layer.
Claim 79
Dependent Claim
17 words
The structure of claim 62 further comprising a third dielectric layer positioned over the second conductive layer.
Claim 80
Dependent Claim
18 words
The structure of claim 63 wherein the third dielectric layer includes syntactic foam proximate the second conductive layer.
Claim 81
Dependent Claim
23 words
The structure of claim 64 wherein the third dielectric layer includes the external most dielectric skin layer remote from the second conductive layer.
Claim 82
Dependent Claim
52 words
The structure of claim 62 wherein at least one of the first and second dipole pattern comprises a repeating square pattern having a plurality of dipoles oriented along each of two perpendicular directions, the square pattern being arranged so that each plurality of dipoles is adjacent another of the plurality of dipoles.
Claim 83
Dependent Claim
33 words
The structure of claim 66 wherein the plurality of dipoles of each square pattern is rotated relative to at least one adjacent square pattern so that a semi-random pattern of dipoles is formed.
Claim 84
Dependent Claim
112 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first resistive layer comprising a first resistive sheet of material having a broken pattern formed thereon and having an impedance in a range of approximately 250-377 ohms, positioned over the first dielectric layer; a second dielectric layer positioned over the first conductive layer; a second resistive layer comprising a second resistive sheet having a broken pattern and having an impedance in a range of approximately 250-377 ohms, positioned over the second dielectric layer; and an external-most dielectric skin layer.
Claim 85
Dependent Claim
112 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first resistive layer comprising a first resistive sheet of material having a broken pattern formed thereon and having an impedance in a range of approximately 250-377 ohms, positioned over the first dielectric layer; a second dielectric layer positioned over the first conductive layer; a second resistive layer comprising a second resistive sheet having a broken pattern and having an impedance in a range of approximately 250-377 ohms, positioned over the second dielectric layer; and an external-most dielectric skin layer.
Claim 86
Dependent Claim
28 words
The structure of claim 68 wherein at least one of the first and second resistive sheets includes a pattern formed therein comprising a plurality of separated geometrical shapes.
Claim 87
Dependent Claim
28 words
The structure of claim 69 wherein the geometrical shapes each comprise an identical square and each identical square is spaced at an equal distance from adjacent identical squares.
Claim 88
Dependent Claim
20 words
The structure of claim 70 wherein each identical square is sized in a range between 0.5 inches and 1.5 inches.
Claim 89
Dependent Claim
46 words
The structure of claim 71 wherein each of the first and second resistive sheets includes a pattern formed therein comprising a plurality of identical squares and wherein the identical squares of the first resistive sheet are larger than the identical squares of the second resistive sheet.
Claim 90
Dependent Claim
26 words
The structure of claim 70 wherein each identical square is spaced from adjacent identical squares a distance in a range of 0.05 inches to 0.10 inches.
Claim 91
Dependent Claim
29 words
The structure of claim 68 wherein at least one of the first resistive layer and the second resistive layer comprises a polymer sheet having a lossy material contained therein.
Claim 92
Dependent Claim
150 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first resistive layer comprising a first broken pattern resistive sheet positioned over the first dielectric layer; a second dielectric layer positioned over the first conductive layer; a second resistive layer comprising a second broken pattern resistive sheet positioned over the second dielectric layer; wherein at least one of the first and the second resistive sheets includes a pattern formed therein comprising a plurality of separated identical squares, wherein each identical square is spaced at an equal distance from adjacent identical squares, and wherein a side of each of the squares includes a narrow runner extending to a side of an adjacent of the squares so that a spacing therebetween is maintained; and an external-most dielectric skin layer.
Claim 93
Dependent Claim
150 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first resistive layer comprising a first broken pattern resistive sheet positioned over the first dielectric layer; a second dielectric layer positioned over the first conductive layer; a second resistive layer comprising a second broken pattern resistive sheet positioned over the second dielectric layer; wherein at least one of the first and the second resistive sheets includes a pattern formed therein comprising a plurality of separated identical squares, wherein each identical square is spaced at an equal distance from adjacent identical squares, and wherein a side of each of the squares includes a narrow runner extending to a side of an adjacent of the squares so that a spacing therebetween is maintained; and an external-most dielectric skin layer.
Claim 94
Dependent Claim
100 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first resistive layer comprising a first broken pattern resistive sheet positioned over the first dielectric layer; a second dielectric layer positioned over the first conductive layer; a second resistive layer comprising a second broken pattern resistive sheet positioned over the second dielectric layer, wherein at least one of the first and the second resistive sheets comprises a carbon black-filled polyimide material; and an external-most dielectric skin layer.
Claim 95
Dependent Claim
100 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface; a first dielectric layer positioned over the electrically conductive surface; a first resistive layer comprising a first broken pattern resistive sheet positioned over the first dielectric layer; a second dielectric layer positioned over the first conductive layer; a second resistive layer comprising a second broken pattern resistive sheet positioned over the second dielectric layer, wherein at least one of the first and the second resistive sheets comprises a carbon black-filled polyimide material; and an external-most dielectric skin layer.
Claim 96
Dependent Claim
23 words
The structure of claim 76 wherein each of the first and the second dielectric layers comprises a material reinforced hardened liquid matrix composite.
Claim 97
Dependent Claim
34 words
The structure of claim 77 wherein the material of at least one of the first dielectric layer and the second dielectric layer includes glass fiber layers and wherein the matrix comprises an epoxy resin.
Claim 98
Dependent Claim
101 words
The structure of claim 77 formed by a process including the steps of: providing layers of material for each of the first dielectric layer and the second dielectric layer to a cavity mold; providing a base structure having the electrically conductive surface thereon and providing the first resistive sheet and the second resistive sheet between predetermined of the layers of material in the cavity mold; and injecting the liquid matrix under pressure so that it passes between each of the layers of material to form an integral structure that joins the first and the second resistive sheets and the base together.
Claim 99
Dependent Claim
17 words
The structure of claim 79 further comprising the step of heat curing the matrix subsequent to injecting.
Claim 100
Dependent Claim
22 words
The structure of claim 79 wherein at least one of the material layers comprises fiberglass and the matrix comprises an epoxy resin.
Claim 101
Dependent Claim
11 words
The structure of claim 81 wherein the fiberglass includes S-glass therein.
Claim 102
Dependent Claim
21 words
The structure of claim 79 wherein at least one of the first and the second resistive sheets comprises Du Pont XC™.
Claim 103
Dependent Claim
13 words
The structure of claim 79 wherein the base comprises a metallic structural member.
Claim 104
Dependent Claim
22 words
The structure of claim 79 wherein the base comprises a plurality of layers of material having the electrically conductive surface positioned thereover.
Claim 105
Dependent Claim
16 words
The structure of claim 85 wherein the electrically conductive surface comprises an expanded mesh copper screen.
Claim 106
Dependent Claim
25 words
The structure of claim 79 wherein at least one of the material layers comprises a combination of at least two of polyimide, polyethelene and fiberglass.
Claim 107
Independent Claim
130 words
A method of forming a radar absorbing structure comprising the steps of: providing a forming surface having a predetermined shape; providing a structural material in a layer over the forming surface; providing an electrically conductive surface over the structural material; providing at least one layer of fibrous material over the electrically conductive surface; providing at least one layer of sheet material formed into a broken pattern, the sheet material being resistive, over the fibrous material; providing an external layer of fibrous material over the resistive material; applying a liquid hardenable matrix to each of the structural material, the fibrous material, the resistive material and the external layer of fibrous material, the matrix passing therebetween; and curing the matrix so that a structural member having the predetermined shape is formed thereby.
Claim 108
Independent Claim
130 words
A method of forming a radar absorbing structure comprising the steps of: providing a forming surface having a predetermined shape; providing a structural material in a layer over the forming surface; providing an electrically conductive surface over the structural material; providing at least one layer of fibrous material over the electrically conductive surface; providing at least one layer of sheet material formed into a broken pattern, the sheet material being resistive, over the fibrous material; providing an external layer of fibrous material over the resistive material; applying a liquid hardenable matrix to each of the structural material, the fibrous material, the resistive material and the external layer of fibrous material, the matrix passing therebetween; and curing the matrix so that a structural member having the predetermined shape is formed thereby.
Claim 109
Dependent Claim
57 words
The method of claim 88 wherein the step of providing the structural material includes providing a material that comprises fiberglass, the step of providing at least one layer of the fibrous material includes providing a material that comprises fiberglass and the step of providing the external layer of fibrous material includes providing a material that comprises fiberglass.
Claim 110
Dependent Claim
23 words
The method of claim 89 wherein the step of applying the liquid hardenable matrix includes providing a matrix that comprises an expoxy resin.
Claim 111
Dependent Claim
29 words
The method of claim 90 wherein the step of providing at least one layer of the sheet material includes providing a polymer sheet having a lossy material contained therein.
Claim 112
Dependent Claim
44 words
The method of claim 88 further comprising, applying a second layer of fibrous material over the resistive layer and applying a second resistive layer over the second layer of fibrous material, the external layer of fibrous material being located over the second resistive layer.
Claim 113
Dependent Claim
202 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface thereon; a first dielectric layer positioned over the electrically conductive surface; a first resistive sheet positioned over the first dielectric layer, the first resistive sheet including a broken pattern comprising a plurality of first geometric shapes having a first predetermined size, the first resistive sheet being spaced from the conductive surface at a first predetermined distance; a second dielectric layer positioned over the first conductive layer; a second resistive sheet positioned over the second dielectric layer, the second resistive sheet including a broken pattern comprising a plurality of second geometric shapes having a second predetermined size, the second resistive sheet being spaced from the conductive surface at a second predetermined distance; and wherein each of the first predetermined size, the first predetermined spacing, the second predetermined size and the second predetermined spacing are sized and arranged so that electromagnetic waves in at least two discrete frequency bands are absorbed, a spectral location of the bands being relative to a value for each of the first predetermined size, the second predetermined size, the first predetermined spacing and the second predetermined spacing.
Claim 114
Dependent Claim
202 words
An electromagnetic energy absorbing structure comprising: a base structure comprising a structural member of an object and including an electrically conductive surface thereon; a first dielectric layer positioned over the electrically conductive surface; a first resistive sheet positioned over the first dielectric layer, the first resistive sheet including a broken pattern comprising a plurality of first geometric shapes having a first predetermined size, the first resistive sheet being spaced from the conductive surface at a first predetermined distance; a second dielectric layer positioned over the first conductive layer; a second resistive sheet positioned over the second dielectric layer, the second resistive sheet including a broken pattern comprising a plurality of second geometric shapes having a second predetermined size, the second resistive sheet being spaced from the conductive surface at a second predetermined distance; and wherein each of the first predetermined size, the first predetermined spacing, the second predetermined size and the second predetermined spacing are sized and arranged so that electromagnetic waves in at least two discrete frequency bands are absorbed, a spectral location of the bands being relative to a value for each of the first predetermined size, the second predetermined size, the first predetermined spacing and the second predetermined spacing.
Claim 115
Dependent Claim
32 words
An electromagnetic energy absorbing structure as set forth in claim 93 wherein each of the first resistive sheet and the second resistive sheet each comprise a polymer having a lossy material therein.
Claim 116
Dependent Claim
27 words
An electromagnetic energy absorbing structure as set forth in claim 93 further comprising a dielectric skin layer having a predetermined thickness positioned over the second resistive sheet.
Claim 117
Dependent Claim
36 words
An electromagnetic energy absorbing structure as set forth in claim 95 wherein each of the first dielectric layer, the second dielectric layer and the skin layer comprise a fibrous material interconnected by a hardened liquid matrix.
Claim 118
Dependent Claim
40 words
An electromagnetic energy absorbing structure as set forth in claim 96 wherein the base structure comprises a fibrous material interconnected to each of the first dielectric layer, the second dielectric layer and the skin layer by the hardened liquid matrix.
Claim 119
Dependent Claim
17 words
An electromagnetic energy absorbing structure as set forth in claim 97 wherein the fibrous material comprises fiberglass.
Claim 120
Dependent Claim
19 words
An electromagnetic energy absorbing structure as set forth in claim 97 wherein the hardened liquid matrix comprises epoxy resin.
Claim 121
Dependent Claim
34 words
An electromagnetic energy absorbing structure as set forth in claim 93 wherein at least one of the first geometric shapes and the second geometric shapes comprise squares, the squares being separated by predetermined distances.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-06-27 | 1997-12-27 | 1998-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-27 | 2001-12-27 | 2002-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-27 | 2005-12-27 | 2006-06-28 | $7700.00 | Window Closed / Lapsed |