Reduced weight artificial dielectric antennas and method for providing the same
First Claim
1. An artificial dielectric structure comprising:
- first and second stacked dielectric layers having first and second permittivities, respectively, said first permittivity being different from said second permittivity,wherein said artificial dielectric structure has a permittivity tensor comprised of permittivity components respectively defined along three principal axes, one of said permittivity components along a certain axis of said principal axes being substantially different than both of the other two of said permittivity components,and wherein said dielectric layers each have substantially parallel top and bottom surfaces and are stacked in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric layer is adjacent to said bottom surface of said second dielectric layer, said certain axis being parallel to said first direction,and wherein said other two of said permittivity components are greater than said one permittivity component along said certain axis by at least a factor of 5,and wherein said first and second dielectric layers have first and second thicknesses t1 and t2, and first and second permittivities ε
r1 and ε
r2 respectively, said first and second thicknesses satisfying the condition that tn <
<
1/β
n, where β
n =ω
×
sqrt(μ
0 ε
0 ε
rn) for n=1,2, and ω
=2π
f where f is the maximum operating frequency of said artificial dielectric structure.
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Abstract
An artificial anisotropic dielectric material is used as a microstrip patch antenna substrate and can achieve dramatic antenna weight reduction. The artificial dielectric is comprised of a periodic structure of low and high permittivity layers. The net effective dielectric constant in the plane parallel to the layers is engineered to be any desired value between the permittivities of the constituent layers. These layers are oriented vertically below the patch to support electric fields consistent with desired resonant modes. Substrates may be engineered for both linearly and circularly polarized patch antennas. Substrate weights can be reduced by factors of from 6 to 30 times using different types of high permittivity layers. This concept has numerous applications in electrically small and lightweight antenna elements, as well as in resonators, microwave lenses, and other electromagnetic devices.
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Citations
43 Claims
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1. An artificial dielectric structure comprising:
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first and second stacked dielectric layers having first and second permittivities, respectively, said first permittivity being different from said second permittivity, wherein said artificial dielectric structure has a permittivity tensor comprised of permittivity components respectively defined along three principal axes, one of said permittivity components along a certain axis of said principal axes being substantially different than both of the other two of said permittivity components, and wherein said dielectric layers each have substantially parallel top and bottom surfaces and are stacked in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric layer is adjacent to said bottom surface of said second dielectric layer, said certain axis being parallel to said first direction, and wherein said other two of said permittivity components are greater than said one permittivity component along said certain axis by at least a factor of 5, and wherein said first and second dielectric layers have first and second thicknesses t1 and t2, and first and second permittivities ε
r1 and ε
r2 respectively, said first and second thicknesses satisfying the condition that tn <
<
1/β
n, where β
n =ω
×
sqrt(μ
0 ε
0 ε
rn) for n=1,2, and ω
=2π
f where f is the maximum operating frequency of said artificial dielectric structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An antenna comprising:
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a radiating element that is adapted to receive RF energy; a metalized ground plane; and a substrate disposed between said radiating element and said metalized ground plane, said substrate comprising at least first and second stacked dielectric layers having first and second permittivities, respectively, said first permittivity being different from said second permittivity, said substrate having a permittivity tensor comprised of permittivity components respectively defined along three principal axes, one of said permittivity components along a certain axis of said principal axes being substantially different than both of the other two of said permittivity components, wherein said dielectric layers each have substantially parallel top and bottom surfaces and are stacked in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric layer is adjacent to said bottom surface of said second dielectric layer, said certain axis being parallel to said first direction, and wherein said other two of said permittivity components are greater than said one permittivity component along said certain axis by at least a factor of 5, and wherein said first and second dielectric layers have first and second thicknesses t1 and t2, and first and second permittivities ε
r1 and ε
r2 respectively, said first and second thicknesses satisfying the condition that tn <
<
1/β
n, where β
n =ω
×
sqrt(μ
0 ε
0 ε
rn) for n=1,2, and ω
=2π
f where f is the maximum operating frequency of said antenna. - View Dependent Claims (14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26)
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19. An antenna comprising:
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a radiating element that is adapted to receive RF energy; a metalized ground plane; and a substrate disposed between said radiating element and said metalized ground plane, said substrate comprising at least first and second stacked dielectric layers having first and second permittivities, respectively, said first permittivity being different from said second permittivity, said substrate having a permittivity tensor comprised of permittivity components respectively defined along three principal axes, one of said permittivity components along a certain axis of said principal axes being substantially different than both of the other two of said permittivity components, wherein said dielectric layers each have substantially parallel top and bottom surfaces and are stacked in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric layer is adjacent to said bottom surface of said second dielectric layer, said certain axis being parallel to said first direction, wherein said radiating element has a surface, said surface being parallel to said first direction.
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27. A patch antenna, comprising:
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a microstrip patch that is adapted to receive RF energy; a metalized ground plane; and a substrate disposed between said microstrip patch and said metalized ground plane, said substrate comprising four artificial dielectric structures, said artificial dielectric structures being arranged so that each artificial dielectric structure is adjacent to two other of said artificial dielectric structures, each artificial dielectric structure having at least first and second stacked dielectric layers having first and second permittivities, respectively, said first permittivity being different from said second permittivity, said each artificial dielectric structure having a permittivity tensor comprised of permittivity components respectively defined along three principal axes, one of said permittivity components along a certain axis of said principal axes being substantially different than both of the other two of said permittivity components, wherein said certain axis of said each artificial dielectric structure is orthogonal to said certain axis of each of said two adjacent artificial dielectric structures, wherein said radiating element is disposed substantially in contact with both said first and second dielectric layers of said each artificial dielectric structure. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A patch antenna, comprising:
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a microstrip patch that is adapted to receive RF energy; a metalized ground plane; and a substrate disposed between said microstrip patch and said metalized ground plane, said substrate comprising four artificial dielectric structures, said artificial dielectric structures being arranged so that each artificial dielectric structure is adjacent to two other of said artificial dielectric structures, each artificial dielectric structure having at least first and second stacked dielectric layers having first and second permittivities, respectively, said first permittivity being different from said second permittivity, said each artificial dielectric structure having a permittivity tensor comprised of permittivity components respectively defined along three principal axes, one of said permittivity components along a certain axis of said principal axes being substantially different than both of the other two of said permittivity components, wherein said certain axis of said each artificial dielectric structure is orthogonal to said certain axis of each of said two adjacent artificial dielectric structures, wherein said dielectric layers of said each artificial dielectric structure each have substantially parallel top and bottom surfaces and are stacked in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric layer is adjacent to said bottom surface of said second dielectric layer, said certain axis of said each artificial dielectric structure being parallel to said first direction, and wherein said patch has a surface, said surface being parallel to said first direction of said four artificial dielectric structures.
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39. A method of providing an antenna substrate with a desired permittivity ε
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d, wherein said antenna substrate is adapted for use in a microstrip patch antenna having a patch with a patch surface, said method comprising;
identifying a first dielectric material having a first permittivity ε
r1 ;identifying a second dielectric material having a second permittivity ε
r2, said first and second dielectric materials each having substantially parallel top and bottom surfaces;adjusting respective first and second thicknesses t1 and t2 between said top and bottom surfaces of said first and second dielectric materials in accordance with said desired permittivity; stacking said first and second dielectric materials in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric material is adjacent to said bottom surface of said second dielectric material; and orienting said stacked first and second dielectric materials so that said first direction is parallel to said patch surface. - View Dependent Claims (40, 41, 42)
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d, wherein said antenna substrate is adapted for use in a microstrip patch antenna having a patch with a patch surface, said method comprising;
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43. A method of reducing the weight of an antenna having a substrate with a desired permittivity and an undesired specific gravity, wherein said antenna substrate is adapted for use in a microstrip patch antenna having a patch with a patch surface, comprising:
- identifying a first dielectric material having a first permittivity ε
r1 and a first specific gravity;identifying a second dielectric material having a second permittivity ε
r2 and a second specific gravity, at least one of said first and second specific gravities being less than said undesired specific gravity, said dielectric materials each having substantially parallel top and bottom surfaces;adjusting respective first and second thicknesses t1 and t2 between said top and bottom surfaces of said first and second dielectric materials in accordance with said desired permittivity and a desired specific gravity less than said undesired specific gravity; stacking said first and second dielectric materials in a first direction perpendicular to said top and bottom surfaces such that said top surface of said first dielectric material is adjacent to said bottom surface of said second dielectric material to form an artificial dielectric structure; replacing said substrate with said artificial dielectric structure; and orienting said stacked first and second dielectric materials so that said first direction is parallel to said patch surface.
- identifying a first dielectric material having a first permittivity ε
Specification