CN210628495U - Transparent antenna cover based on optical transformation - Google Patents
Transparent antenna cover based on optical transformation Download PDFInfo
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- CN210628495U CN210628495U CN201922207503.7U CN201922207503U CN210628495U CN 210628495 U CN210628495 U CN 210628495U CN 201922207503 U CN201922207503 U CN 201922207503U CN 210628495 U CN210628495 U CN 210628495U
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Abstract
The utility model discloses a transparent antenna house based on optics transform belongs to the electromagnetic technology field. The antenna housing is a vertical columnar structure, the cross section of the columnar structure is a polygon, the antenna housing comprises an antenna space for placing an antenna and two layers of metamaterial cover bodies surrounding the antenna space, the center of the cross section of each metamaterial cover body coincides with the center of the cross section of the columnar structure, and the shape of the cross section of each metamaterial cover body is the same as that of the cross section of the columnar structure. The antenna housing performs stretching transformation and compression transformation in a transformation space, can realize no reflection and transmission of electromagnetic waves on an interface due to impedance matching of an optical transformation medium and a surrounding medium, limits the change of the electromagnetic waves realized through the optical transformation in a transformation area, and does not transmit the space outside the transformation area, so that a transparent structure is formed for the electromagnetic waves in any direction, and the antenna is transparent for any frequency.
Description
Technical Field
The utility model belongs to the technical field of the electromagnetism, specifically speaking relates to a transparent antenna house based on optics transform.
Background
Antennas constructed from metal are subject to oxidation and attack by contaminants over time, particularly outdoor antennas, and by rain and snow, bird droppings, acidic and basic contaminants in the air, which can lead to structural damage and performance degradation. In order to prolong the service life of the antenna and avoid the influence of environmental climate factors on the antenna, the antenna can be effectively protected by adding the antenna cover around the antenna. The radome is an important structure for protecting an antenna system from the external environment, as a protection device for the antenna, which physically isolates the antenna from the external environment.
An ideal radome should have good electromagnetic wave penetration characteristics. However, the conventional radome is usually formed by coating a transparent medium with a certain thickness and small dissipation on the surface of the antenna, but still has the defects of interface reflection, medium loss and the like, so that the working distance of the antenna is shortened, the radiation angle is deviated, and the receiving and transmitting performance of the antenna is affected. Therefore, the use of the conventional radome inevitably affects the performance of the antenna system for receiving and transmitting electromagnetic signals, and therefore, in the design of the radome, it is very important to optimize the external structure and the electromagnetic characteristics of the radome.
In the prior art, a transparent structure (Fang Y, He s. transparent structures of metallic and metallic layers [ J ]. Physical ReviewA, 2008, 78 (2): 023813.) has been proposed, which consists of a DNG metamaterial layer and a matching ENG material, i.e. a negative refractive index material, and which is furthermore a one-dimensional structure that is omnidirectionally transparent to any polarized electromagnetic waves incident from the outside. Since electromagnetic waves cannot be radiated from the inside (without a position where the antenna is installed) and transparency cannot be guaranteed even if the electromagnetic waves can be radiated from the inside, although the document proposes to assume that the transparent structure is applied to a radome having a periodic structure to improve the transmittance of a conventional radome, a specific application mode is not given, and practical application is difficult.
Disclosure of Invention
To the above-mentioned problem that prior art exists, the utility model aims to provide a transparent antenna house based on optics transform has unique optical characteristic and electromagnetic propagation mode, is suitable for the practicality.
In order to solve the above problem, the technical scheme of the utility model is as follows:
the utility model provides a transparent antenna house based on optics transform, the antenna house is perpendicular columnar structure, columnar structure's cross section is the polygon, the antenna house is including the antenna space that is used for placing the antenna and the two-layer metamaterial cover body that surrounds it, the center of the cross section of the metamaterial cover body with the center coincidence of columnar structure's cross section, the shape of the cross section of the metamaterial cover body with columnar structure's cross section is the same.
Further, the polygon is a triangle or a square.
Further, the relative permittivity and permeability tensor of the metamaterial cover body are as follows:
wherein, b11＝a11 2+a12 2，b12＝b21＝a11a12+a21a22，b22＝a21 2+a22 2，k4＝a11a22+a12a21；
In the above formula, a11＝k1+k3y，a12＝-xk3，
In the above formula, k1＝(m-c)/(m-b)，k2＝m(1-k1) X and y are any point in spaceThe position coordinates of (a).
The two-layer metamaterial cover body comprises a first layer cover body and a second layer cover body, and the space area of the antenna is S1The second layer of cover body area is S4Dividing the first layer cover body area into S2And S3Connecting the center point of the cross section with each vertex of the polygon to divide the cross section into a plurality of isosceles triangle areas, wherein each isosceles triangle area consists of 4 isosceles triangles, the distances from the bottom edges of the four isosceles triangles to the center point are a, b, c and d from small to large, in the formula, r is the distance from the center of the cover body to the side of the triangle, and if S is the distance from the center of the cover body to the side of the triangle3＜r＜S4If m is d, if S1＜r＜S3And m is a,.
Compared with the prior art, the beneficial effects of the utility model are that:
(1) the antenna housing of the utility model realizes two times of coordinate transformation in the transformation space, and can realize the reflection-free transmission of electromagnetic waves on the interface due to the impedance matching of the optical transformation medium and the surrounding medium; the change of the electromagnetic wave by the optical transformation is limited in the transformation area, and the space outside the transformation area is not transmitted, so that the structure is transparent to the electromagnetic wave in any direction, and the antenna is transparent to any frequency.
(2) Compare traditional antenna house structure, the utility model discloses an antenna house simple structure, reasonable in design easily realizes, can reach fine transmission effect moreover.
(3) The utility model discloses an adjustment of shape can be carried out according to antenna line shape and actual need to the antenna house, and application scope is wider.
Drawings
Fig. 1 is the utility model discloses a structural schematic diagram of regular triangle transparent radome.
FIG. 2 shows an electric field E when an electromagnetic wave passes through a triangular radomezAnd the distribution in space is that the electromagnetic wave with the polarization direction along the incident plane of the z axis is incident from the left interface to the right.
FIG. 3 shows an electric field E when an electromagnetic wave passes through a triangular radomezIn a spatial distribution, when two-dimensionalThe line source is located at the coordinate (-0.3m, 0) to generate electromagnetic waves along the z-axis direction.
FIG. 4 shows an electric field E when an electromagnetic wave passes through a triangular radomezIn the distribution of space, the two-dimensional line source is positioned at the origin of coordinates to generate electromagnetic waves along the direction of the z-axis.
Fig. 5 is the utility model discloses a structure schematic diagram of rectangle transparent antenna cover structure.
FIG. 6 shows an electric field E when an electromagnetic wave passes through a rectangular radomezAnd the distribution in space is that the electromagnetic wave with the polarization direction along the incident plane of the z axis is incident from the left interface to the right.
FIG. 7 shows an electric field E when an electromagnetic wave passes through a rectangular radomezIn the spatial distribution, the two-dimensional line source is located at the coordinate (-0.3m, 0) to generate electromagnetic waves along the z-axis direction.
FIG. 8 shows an electric field E when an electromagnetic wave passes through a rectangular radomezIn the distribution of space, the two-dimensional line source is positioned at the origin of coordinates to generate electromagnetic waves along the direction of the z-axis.
Detailed Description
The present invention will be further described with reference to the following specific embodiments.
The utility model provides a transparent antenna house based on optics transform, the antenna house is perpendicular columnar structure, and columnar structure's cross section is the polygon, and the antenna house is including the antenna space that is used for placing the antenna and the two-layer metamaterial cover body that surrounds it, by interior and the outer first layer cover body and the second floor cover body of being respectively, and the center of the cross section of the metamaterial cover body coincides with the center of columnar structure's cross section, and the shape of the cross section of the metamaterial cover body is the same with columnar structure's cross section.
The polygon can be designed into a triangle, a square, a diamond, a pentagon, a hexagon and the like according to requirements.
The optical transformation idea of the antenna housing model is as follows: in the cylindrical coordinate system, (r, theta, z) is the coordinate of a space point before transformation, and (r ', theta ', z ') is the corresponding space point coordinate after coordinate transformation.
For a two-dimensional n-polygon structure, four n-polygons with different proportional sizes can be used to divide the space into 5 regions, S1、S2、S3、S4、S5: spatial area of the antenna is S1The first layer of cover body area is divided into S2And S3(in FIGS. 1 and 5, S2And S3Separated by a dashed line), also called stretch zone, the second shell zone being S4Also called compression area, S5Is an external free space. The cross section of the metamaterial cover body can be divided into a plurality of isosceles triangle areas (the three-side structure is divided into 3 triangles, the four-side structure is divided into 4 triangles, and the division can be completed by connecting the central point O with each vertex of the polygon) according to the S1～S5The area division of (2) shows that each triangular area comprises 4 isosceles triangles, and the distances from the bottom edges of the 4 isosceles triangles to the central point are respectively a, b, c and d from small to large.
For any of the divided isosceles triangle areas, first, S is retained1And S4Is not changed, and secondly, S is changed3And S4Compression to S4Then, S is2Is stretched to S2And S3. To realize the above changing idea, the corresponding transformation (the isosceles triangle area with the y axis as the symmetry axis in fig. 1, and the isosceles triangle area with the x axis as the symmetry axis in fig. 5) is:
θ′＝θ (2)
z′＝z (3)
wherein k is1＝(m-c)/(m-b)，k2＝m(1-k1) And (r, theta, z) is expressed as the position of a point in space before transformation in the cylindrical coordinates, and (r ', theta ', z ') is expressed as the position of a point in space after transformation in the cylindrical coordinates. In the above formula, let r be the distance from the center of the cover body to the triangle side, if S3＜r＜S4If m is d, corresponding to the compression region; if S is1＜r＜S3And m ═ a, corresponds to the stretch region. The value of k1 determines the ratio of compression to tension.
Thus, the rectangular coordinates can be obtainedTransformation matrix of transformation space in system (x, y, z) (x, y, z are coordinates of a certain point in space in rectangular coordinate system respectively)
The form is as follows:
wherein, a11＝k1+k3y，a12＝-xk3，
The relative permittivity and permeability of the transformation space can be expressed as (where the subscript r denotes the relative permittivity and relative permeability):
wherein, b11＝a11 2+a12 2，b12＝b21＝a11a12+a21a22，b22＝a21 2+a22 2，k4＝a11a22+a12a21. It can be seen that the permittivity and permeability in the transformed region are anisotropic. Since the form invariance of Maxwell equation is ensured before and after transformation in the transformation space, the free space is transformed into a structure composed of artificial materials in the transformation, and the propagation characteristic of free space electromagnetic wave is still maintained.
The permittivity and permeability tensors of the other triangular regions can be obtained in the same way.
Example 1
In the present embodiment, the cross section of the cylindrical structure of the radome is designed as a regular triangle, see fig. 1, and the distances from the center of the triangle to each side are respectively 0.06m, 0.065m, 0.075m, and 0.09 m.
Fig. 2 shows the spatial distribution of the electric field Ez when the electromagnetic wave passes through the triangular radome, and a two-dimensional (2D) transverse electric polarization (TE) incident wave (the electric field of which is along the z direction) is adopted, at which time the electromagnetic wave is incident from the left interface to the right along the incident plane of the z axis. The selection frequency is 4GHz, and the numerical simulation is based on a finite element method to simulate the triangular transparent antenna housing. As can be seen from FIG. 2, when the wave enters the transformation zone, there is no reflected wave in the interface, the incident wave remains unchanged, and the electromagnetic wave is in the transformation zone (zone S)2～S4) Distortion occurs. When the wave propagates to S1In the region, the propagation state of the wave is kept unchanged, which means that the structure is transparent to the electromagnetic wave, and the electromagnetic wave is also unchanged and propagates in the original direction after being transmitted through the antenna housing.
FIG. 3 shows an electric field E when an electromagnetic wave passes through a triangular radomezIn the spatial distribution, a two-dimensional line source Il is 10-3Am-1Located at the left side (-0.3m, 0) of the transformation space, where the generated cylindrical wave passes through the transformation space in the z-axis direction, it can be seen that the electric field is stretched and compressed in the transformation space, but S is inside it1And an external free space, the electric field in turn restoring the properties of the cylindrical wave. Therefore, although there is a transformation space, the characteristics of the original field can be maintained in the inner and outer regions, that is, transparency to electromagnetic waves is realized.
FIG. 4 shows an electric field E when an electromagnetic wave passes through a triangular radomezIn the spatial distribution, the current is Il-10-3Am is located at the origin of coordinates, i.e. S1Of the center of (c). It can be seen that after the conversion structure, the shape of the cylindrical wave is restored as if the entire transformation did not exist. Since the conversion medium is matched to the surrounding medium, the wave propagates in the conversion medium, at S1Inner boundary and S of4Without any reflection, i.e. transparency to electromagnetic waves is achieved.
Example 2
In the present embodiment, the cross section of the cylindrical structure of the radome is designed to be rectangularSee fig. 5, a ═ b1＝2a1＝0.16m，b＝b2＝2a2＝0.20m，c＝b3＝2a3＝0.28m，d＝b4＝2a4The optical transformation of the rectangular transparent radome is similar to the triangular transparent radome of example 1, i.e. 0.32 m.
FIG. 6 shows an electric field E when an electromagnetic wave passes through a rectangular radomezAnd the distribution in space is that the electromagnetic wave with the polarization direction along the incident plane of the z axis is incident from the left interface to the right. It can be seen that when the wave enters the transformation zone, there is no reflected wave in the interface, the incident wave remains unchanged, and the electromagnetic wave is in the transformation zone (zone S)2～S4) Distortion occurs. When the wave propagates to S1In the region, the propagation state of the wave remains unchanged, indicating that the structure is transparent to electromagnetic waves. After being transmitted through the antenna housing, the electromagnetic wave is unchanged and propagates in the original direction.
FIG. 7 shows an electric field E when an electromagnetic wave passes through a rectangular radomezIn the spatial distribution, a two-dimensional line source Il is 10-3Am-1Located at the left side (-0.3m, 0) of the transformation space, where the generated cylindrical wave passes through the transformation space in the z-axis direction, and the electric field is stretched and compressed but inside S1And an external free space S5The electric field in turn restores the characteristics of the cylindrical wave. Therefore, although there is a transformation space, the characteristics of the original field can be maintained in the inner and outer regions.
FIG. 8 shows an electric field E when an electromagnetic wave passes through a rectangular radomezIn the distribution of space, the two-dimensional line source is positioned at the origin of coordinates to generate electromagnetic waves along the direction of the z-axis. It can be seen that the electric field can restore the cylindrical wave characteristics after passing through the radome.
Claims (3)
1. The utility model provides a transparent antenna house based on optics transform, its characterized in that, the antenna house is perpendicular column structure, column structure's cross section is the polygon, the antenna house is including the antenna space that is used for placing the antenna and the two-layer metamaterial cover body that surrounds it, the center of the cross section of the metamaterial cover body with the center coincidence of column structure's cross section, the shape of the cross section of the metamaterial cover body with column structure's cross section is the same.
2. The optical transform-based transparent radome of claim 1, wherein the polygon is a triangle or a square.
3. The optical transformation based transparent radome of claim 1 or 2, wherein the metamaterial cover has a relative permittivity and permeability tensor of:
wherein, b11＝a11 2+a12 2，b12＝b21＝a11a12+a21a22，b22＝a21 2+a22 2，k4＝a11a22+a12a21；
In the above formula, a11＝k1+k3y，a12＝-xk3，
In the above formula, k1＝(m-c)/(m-b)，k2＝m(1-k1) X and y are the position coordinates of any point in space;
the two-layer metamaterial cover body comprises a first layer cover body and a second layer cover body, and the space area of the antenna is S1The second layer of cover body area is S4Dividing the first layer cover body area into S2And S3Connecting the center point of the cross section with each vertex of the polygon to divide the cross section into a plurality of isosceles triangle areas, each isosceles triangle area consists of 4 isosceles triangles, and four isosceles trianglesThe distances from the bottom edge of the shape to the central point are a, b, c and d from small to large, in the above formula, r is the distance from the center of the cover body to the side of the triangle, if S is3＜r＜S4If m is d, if S1＜r＜S3And m is a.
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| CN201922207503.7U CN210628495U (en) | 2019-12-10 | 2019-12-10 | Transparent antenna cover based on optical transformation |
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Granted publication date: 20200526 Termination date: 20201210 |