US5693429A
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Electronically graded multilayer ferroelectric composites
Assignee: United States Department of the Army
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Filing: 1996-05-13
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Granted: 1997-12-02
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Expires: 2016-05-13
Abstract
Abstract A laminated ceramic ferroelectric material has adjacent layers of Barium Strontium Titanate (BSTO)-oxide composite stacked in order of descending oxide content and sized in thickness to produce a generally equal capacitance across each layer, resulting in a material having a graded dielectric constant for use in phased array antenna, for example. The oxides are from the metallic oxide group consisting of alumina, zirconia and magnesia and the layers are produced by tape casting.
Inventors
- 👤 Louise C. Sengupta
- 👤 Eric Ngo
- 👤 Michelina E. O'Day
- 👤 Steven Stowell
- 👤 Robert Lancto
- 👤 Somnath Sengupta
- 👤 Thomas V. Hynes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:17
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; B; B32; B32B; B32B18/00; H; H01; H01Q; H01Q1/00; H01Q1/36; H01Q1/38; H01Q3/00; H01Q3/26; H01Q3/30; H01Q3/34; H01Q3/36; H01Q3/44; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/343; C04B2237/345; C04B2237/346; C04B2237/348; C04B2237/50; C04B2237/58; C04B2237/70; C04B2237/704
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
115 words
A laminated ceramic ferrolectric material having a graded dielectric constant comprising a plurality of adjacent layers, said layers having no air gaps between the discrete layers and formed of a composition comprising 0 to 100% of Ba 1-x Sr x TiO 3 wherein x is greater than 0.0 but less than 0.75, and 100 to 0% by weight of at least one low dielectric constant low dielectric loss oxide selected from the group consisting of Al 2 O 3 ZrO 2 and MgO, wherein the ratio of said Ba 1-x Sr x TiO 3 to said oxide is different in each layer, said layers being arranged in order of decreasing dielectric constant and laminated together.
Claim 2
Dependent Claim
115 words
A laminated ceramic ferrolectric material having a graded dielectric constant comprising a plurality of adjacent layers, said layers having no air gaps between the discrete layers and formed of a composition comprising 0 to 100% of Ba 1-x Sr x TiO 3 wherein x is greater than 0.0 but less than 0.75, and 100 to 0% by weight of at least one low dielectric constant low dielectric loss oxide selected from the group consisting of Al 2 O 3 ZrO 2 and MgO, wherein the ratio of said Ba 1-x Sr x TiO 3 to said oxide is different in each layer, said layers being arranged in order of decreasing dielectric constant and laminated together.
Claim 3
Dependent Claim
23 words
The laminated ceramic ferroelectric material of claim 1 wherein the thickness of said layers varies inversely with the barium-strontium-titanate content of said layers.
Claim 4
Dependent Claim
28 words
The laminated ceramic ferroelectric material of claim 1 wherein the thickness of each of said layers is selected to produce a constant capacitance across each of said layers.
Claim 5
Dependent Claim
53 words
The laminated ceramic ferroelectric material of claim 3 wherein the thicknesses of said layers are determined in accordance with the equation ε'=Ct/Aε 0 where ε' is the dielectric constant of said layer, C is the capacitance of barium-strontium-titanate, t is the thickness of said layer, and A is the area of said material.
Claim 6
Dependent Claim
32 words
The laminated ceramic ferroelectric material of claim 1 wherein said ratios of Ba 1-x Sr x TiO 3 to oxide are selected and arranged to produce a linear grading of dielectric constant.
Claim 7
Dependent Claim
35 words
The laminated ceramic ferroelectric material of claim 1 wherein said ratios of Ba 1-x Sr x TiO 3 to oxide are selected and arranged to produce increments of dielectric grading following a predetermined non-linear function.
Claim 8
Dependent Claim
30 words
The laminated ceramic ferroelectric material of claim 1 wherein said low dielectric constant, low dielectric loss oxide is selected from the group consisting of alumina, zirconia, magnesia and mixtures thereof.
Claim 9
Dependent Claim
49 words
The laminated ceramic ferroelectric material of claim 1 wherein said layers are laminated together by heating said arranged layers to a temperature in the range of 150° to 400° C., uniaxially pressing said layers to a pressure in the range of 5000 to 10,000 psi and sintering said layers.
Claim 10
Dependent Claim
45 words
The laminated ceramic ferroelectric material of claim 1 wherein said layers are laminated together by pressing said layers in a warm isostatic press to a pressure in the range of 5000 to 10,000 psi at a temperature of about 70° C. and sintering said layers.
Claim 11
Dependent Claim
131 words
A laminated ceramic ferrolectric material having a selectively graded dielectric constant comprising a plurality of adjacent layers; said layers having no air gap between the discrete layers, each formed of composition of materials selected from the group consisting of Ba 1-x Sr x TiO 3 where x is greater than 0.00 but less than 0.75, at least one dielectric constant, low dielectric loss oxide and a low dielectric constant, low dielectric loss adjusting material, wherein the total combined % by weight of said Ba 1-x Sr x TiO 3 , said oxide and said adjusting material equals 100% and each of said compositions contain a different ratio of said materials to produce layers having different dielectric constants; said layers being arranged in order of of decreasing dielectric constant and laminated together.
Claim 12
Dependent Claim
131 words
A laminated ceramic ferrolectric material having a selectively graded dielectric constant comprising a plurality of adjacent layers; said layers having no air gap between the discrete layers, each formed of composition of materials selected from the group consisting of Ba 1-x Sr x TiO 3 where x is greater than 0.00 but less than 0.75, at least one dielectric constant, low dielectric loss oxide and a low dielectric constant, low dielectric loss adjusting material, wherein the total combined % by weight of said Ba 1-x Sr x TiO 3 , said oxide and said adjusting material equals 100% and each of said compositions contain a different ratio of said materials to produce layers having different dielectric constants; said layers being arranged in order of of decreasing dielectric constant and laminated together.
Claim 13
Dependent Claim
31 words
The laminated ceramic ferroelectric material of claim 10 wherein said low dielectric constant, low dielectric loss adjusting material is selected from the group consisting of polymer and silica and mixtures thereof.
Claim 14
Dependent Claim
45 words
The laminated ceramic ferroelectric material of claim 10 wherein said ratios of Ba 1-x Sr x TiO 3 , said oxide and said adjusting material are selected to produce selected increments of dielectric grading and said layers are arranged to follow a predetermined mathematical function.
Claim 15
Dependent Claim
24 words
The laminated ceramic ferroelectric material of claim 10 wherein said oxide is selected from the group consisting of alumina, zirconia and magnesia, mixtures thereof.
Claim 16
Dependent Claim
49 words
The laminated ceramic ferroelectric material of claim 10 wherein said layers are laminated together by heating said arranged layers to a temperature in the range of 150° to 400° C., uniaxially pressing said layers to a pressure in the range of 5000 to 10,000 psi and sintering said layers.
Claim 17
Dependent Claim
45 words
The laminated ceramic ferroelectric material of claim 10 wherein said layers are laminated together by pressing said layers in a warm isostatic press to a pressure in the range of 5000 to 10,000 psi at a temperature of about 70° C. and sintering said layers.
Claim 18
Dependent Claim
23 words
The laminated ceramic ferroelectric material of claim 10 wherein said adjusting material comprises 0 to 20% by weight of the total material weight.
References Cited (Backward Citations)
US5312790A
Cited
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