Man-made composite material and man-made composite material antenna
View Patent ↗The present invention relates to a man-made composite material and a man-made composite material antenna. The man-made composite material is disposed in a propagation direction of a plane electromagnetic wave and convert it into a spherical wave. Reverse extensions of the spherical wave intersect at a virtual focus. A line connecting the virtual focus to a point on the second surface of the man-made composite material and a line perpendicular to the man-made composite material form an angle θ therebetween, which uniquely corresponds to a curved surface in the man-made composite material. A set formed by points having the same angle θ forms a boundary of the curved surface to which the angle θ uniquely corresponds. Each point on the curved surface to which the angle θ uniquely corresponds has a same refractive index. Refractive indices of the man-made composite material increase gradually as the angle θ increases.
1. A man-made composite material having a thickness between a first and second surface, configured such that the first and second surfaces are perpendicularly disposed to a propagation direction of a plane electromagnetic wave, a curved surface within the man-made material that extends through the thickness, wherein the plane electromagnetic wave is incident on the first surface of the man-made composite material, a spherical electromagnetic wave exits from the second surface of the man-made composite material, and reverse extensions of the exiting spherical electromagnetic wave intersect with each other at a virtual focus of the man-made composite material;
a set of first straight lines connecting the virtual focus to a corresponding set of points on a circular boundary line between the curved surface and the second surface of the man-made composite material, and
a second straight line perpendicular to the man-made composite material, wherein each first straight line forms an angle θ with the second straight line, wherein the same angle θ corresponds to each of the points in the set;
additional sets of first straight lines connecting the virtual focus to additional corresponding sets of points along the curved surface, wherein
each additional set of points on the curved surface form a circular line and has a same uniquely corresponding angle θ and a same refractive index;
the curved surface has a generatrix which extends along a direction of the thickness of the man-made composite material and between the first surface and the second surface is formed by rotating the generatrix about the second straight line; and refractive indices of the man-made composite material increase gradually as the angle θ increases.
2. The man-made composite material of claim 1 , wherein a refractive index distribution of the curved surface satisfies:
n
(
θ
)
=
1
S
(
θ
)
[
(
F
+
d
)
cos
θ
-
(
F
+
d
)
+
n
min
d
]
,
where, S(θ) is an arc length of a generatrix of the curved surface, F is a distance from the virtual focus to the man-made composite material; d is a thickness of the man-made composite material; and n min is a minimum refractive index of the man-made composite material.
3. The man-made composite material of claim 2 , wherein the generatrix of the curved surface is a parabolic arc or an elliptical arc.
4. The man-made composite material of claim 3 , wherein the arc length S(θ) of the parabolic arc satisfies:
S
(
θ
)
=
d
2
[
log
(
tan
θ
+
1
+
tan
2
θ
)
+
δ
tan
θ
+
δ
+
1
+
tan
2
θ
]
,
where δ is a preset decimal.
5. The man-made composite material of claim 4 , wherein when a line passing through a center of the second surface of the man-made composite material and perpendicular to the man-made composite material is taken as an abscissa axis and a line passing through the center of the second surface of the man-made composite material and parallel to the second surface is taken as an ordinate axis an equation of a parabola where the parabolic arc is located is represented as:
y
(
x
)
=
tan
θ
(
-
1
2
d
x
2
+
x
+
F
+
d
)
.
6. The man-made composite material of claim 5 , wherein the angle θ and each point (x, y) of the parabolic arc satisfy the following relational expression:
θ
(
x
,
y
)
=
tan
1
[
2
dy
2
d
(
F
+
d
+
x
)
-
x
2
]
.
7. The man-made composite material of claim 3 , wherein when a line passing through a center of the second surface of the man-made composite material and perpendicular to the man-made composite material is taken as an abscissa axis and a line passing through the center of the second surface of the man-made composite material and parallel to the second surface is taken as an ordinate axis, an equation of an ellipse where the elliptical arc is located is represented as:
(
x
-
d
)
2
a
2
+
(
y
-
c
)
2
b
2
=
1
;
where a, b and c satisfy the following relationships:
d
2
a
2
+
[
(
F
+
d
)
tan
θ
-
c
]
2
b
2
=
1
;
sin
θ
n
2
(
θ
)
-
sin
2
(
θ
)
=
b
2
a
2
d
(
F
+
d
)
tan
θ
-
c
.
8. The man-made composite material of claim 7 , wherein a center of the ellipse where the elliptical arc is located is located on the first surface and has coordinates (d, c).
9. The man-made composite material of claim 7 , wherein a point on the second surface corresponding to the angle θ has a refraction angle θ′, and a refractive index n(θ) of the point satisfies:
n
(
θ
)
=
sin
θ
sin
θ
′
.
10. The man-made composite material of claim 2 , wherein the man-made composite material comprises at least one man-made composite material sheet layer, each of which comprises a sheet-like substrate and a plurality of man-made microstructures attached on the substrate, and each of the man-made microstructures is a two-dimensional (2D) or three-dimensional (3D) structure comprising at least one metal wire and having a geometric pattern, and is of an I shape, a cross shape, or an elliptical shape.
11. A man-made composite material antenna having a thickness between a first and second surface, comprising a radiation source and a man-made composite material configured such that the first and second surfaces are perpendicularly disposed to a propagation direction of a plane electromagnetic wave, a curved surface within the man-made material that extends through the thickness, wherein the plane electromagnetic wave is incident on the first surface of the man-made composite material, a spherical electromagnetic wave exits from the second surface of the man-made composite material, and reverse extensions of the exiting spherical electromagnetic wave intersect with each other at a virtual focus of the man-made composite material;
a set of first straight lines connecting the virtual focus to a corresponding set of points on a circular boundary line between the curved surface and the second surface of the man-made composite material, and
a second straight line perpendicular to the man-made composite material, wherein each first straight line forms an angle θ with the second straight line, wherein the same angle θ corresponds to each of the points in the set;
additional sets of first straight lines connecting the virtual focus to additional corresponding sets of points along the curved surface, wherein
each additional set of points on the curved surface form a circular line and has a same uniquely corresponding angle θ and a same refractive index;
the curved surface has a generatrix which extends along a direction of the thickness of the man-made composite material and between the first surface and the second surface is formed by rotating the generatrix about the second straight line; and refractive indices of the man-made composite material increase gradually as the angle θ increases.
12. The man-made composite material antenna of claim 11 , wherein a refractive index distribution of the curved surface satisfies:
n
(
θ
)
=
1
S
(
θ
)
[
(
F
+
d
)
cos
θ
-
(
F
+
d
)
+
n
min
d
]
,
where, S(θ) is an arc length of a generatrix of the curved surface, F is a distance from the virtual focus to the man-made composite material; d is a thickness of the man-made composite material; and n min is a minimum refractive index of the man-made composite material.
13. The man-made composite material antenna of claim 12 , wherein the generatrix of the curved surface is a parabolic arc or an elliptical arc.
14. The man-made composite material antenna of claim 13 , wherein the arc length S(θ) of the parabolic arc satisfies:
S
(
θ
)
=
d
2
[
log
(
tan
θ
+
1
+
tan
2
θ
)
+
δ
tan
θ
+
δ
+
1
+
tan
2
θ
]
,
where δ is a preset decimal.
15. The man-made composite material antenna of claim 14 , wherein when a line passing through a center of the second surface of the man-made composite material and perpendicular to the man-made composite material is taken as an to abscissa axis and a line passing through the center of the second surface of the man-made composite material and parallel to the second surface is taken as an ordinate axis, an equation of a parabola where the parabolic arc is located is represented as:
y
(
x
)
=
tan
θ
(
-
1
2
d
x
2
+
x
+
F
+
d
)
.
16. The man-made composite material antenna of claim 15 , wherein the angle θ and each point (x, y) of the parabolic arc satisfy the following relational expression:
θ
(
x
,
y
)
=
tan
1
[
2
dy
2
d
(
F
+
d
+
x
)
-
x
2
]
.
17. The man-made composite material antenna of claim 13 , wherein when a line passing through a center of the second surface of the man-made composite material and perpendicular to the man-made composite material is taken as an abscissa axis and a line passing through the center of the second surface of the man-made composite material and parallel to the second surface is taken as an ordinate axis, an equation of an ellipse where the elliptical arc is located is represented as:
(
x
-
d
)
2
a
2
+
(
y
-
c
)
2
b
2
=
1
;
where a, b and c satisfy the following relationships:
d
2
a
2
+
[
(
F
+
d
)
tan
θ
-
c
]
2
b
2
=
1
;
sin
θ
n
2
(
θ
)
-
sin
2
(
θ
)
=
b
2
a
2
d
(
F
+
d
)
tan
θ
-
c
.
18. The man-made composite material antenna of claim 17 , wherein a center of the ellipse where the elliptical arc is located is located on the first surface and has coordinates (d, c).
19. The man-made composite material antenna of claim 17 , wherein a point on the second surface corresponding to the angle θ has a refraction angle θ′, and a refractive index n(θ) of the point satisfies:
n
(
θ
)
=
sin
θ
sin
θ
′
.
20. The man-made composite material antenna of claim 12 , wherein the man-made composite material comprises at least one man-made composite material sheet layer, each of which comprises a sheet-like substrate and a plurality of man-made microstructures attached on the substrate, and each of the man-made microstructures is a 2D or 3D structure having a geometric pattern, and is of a cross shape or a snowflake shape.