WO2013016938A1

WO2013016938A1 - Base station antenna

Info

Publication number: WO2013016938A1
Application number: PCT/CN2011/084632
Authority: WO
Inventors: 刘若鹏; 季春霖; 岳玉涛; 洪运南
Original assignee: 深圳光启高等理工研究院; 深圳光启创新技术有限公司
Priority date: 2011-07-29
Filing date: 2011-12-26
Publication date: 2013-02-07

Abstract

The present invention relates to a base station antenna, including an antenna module having several oscillators arranged in array and a super material module arranged opposite to these oscillators. The super material module includes at least one super material slice layer, each super material slice layer corresponding to the area of each oscillator to form a refractive index distribution area, each refractive index distribution area forming several concentric refractive index circles centred at the centre of the corresponding oscillator. The refractive index of each point on the same refractive index circle is identical, the refractive index of each refractive index circle reduces in the direction away from the centre of the circle and the reduction amount increases, so that the semi-power bandwidth of the electromagnetic waves emitted by the oscillators reduces after passing through the super material module, i.e. the electromagnetic waves can be transmitted farther, improving the directivity and gain of the base station antenna.

Description

Base station antenna

This application claims the priority of the Chinese Patent Application entitled "Base Station Antenna" submitted by the China Patent Office on July 29, 2011, and the application number is 201110216327.9. It was submitted to the Chinese Patent Office on July 29, 2011, and the application number is 201110216339.1. The priority of the Chinese patent application entitled "Base Station Antenna", the priority of the Chinese Patent Application entitled "Base Station Antenna", submitted to the China Patent Office on July 29, 2011, application number 201110215581.7, 2011 7 The priority of the Chinese Patent Application No. 201110215452.8, entitled "Base Station Antenna", is hereby incorporated by reference. Technical field

The present invention relates to the field of electromagnetic communications, and more particularly to a base station antenna. Background technique

The base station antenna is an important device for ensuring wireless access of the mobile communication terminal. With the development of mobile communication networks, the distribution of base stations is becoming more and more dense, and higher requirements are placed on the directivity of base station antennas to avoid mutual interference and to allow electromagnetic waves to travel farther.

In general, we use a half power angle to indicate the directivity of the base station antenna. In the power pattern, the angle between the two points at which the relative maximum radiation direction power flux density is reduced to half (or less than the maximum value of 3 dB) in a plane containing the maximum radiation direction of the main lobe is called half power. angle. In the field strength pattern, the angle at which the field strength relative to the maximum radiation direction is reduced to 0.707 times in a plane containing the maximum radiation direction of the main lobe is also called the half power angle. The half power angle is also known as the half power bandwidth (herein used). The half power bandwidth includes the horizontal half power bandwidth and the vertical plane half power bandwidth. The propagation distance of the electromagnetic wave of the base station antenna is determined by the vertical half-power bandwidth. The smaller the half-power bandwidth of the vertical plane is, the larger the gain of the base station antenna is, and the farther the electromagnetic wave travels. On the contrary, the smaller the gain of the base station antenna, the closer the electromagnetic wave propagation distance is. Summary of the invention

The technical problem to be solved by the present invention is to provide a base station antenna with a small half power bandwidth and good directivity.

The invention provides a base station antenna, comprising an antenna module having a plurality of vibrators arranged in an array and a meta-material module disposed on the vibrators, the meta-material module comprising at least one meta-material sheet, each super-material sheet layer forming a refractive index distribution region corresponding to each vibrator region, each refractive index distribution region being positive The center of the corresponding vibrator is centered to form a plurality of concentric refractive index circles, and the refractive indices of the points on the same refractive index circle are the same, and the refractive index of each refractive index circle decreases in a direction away from the center of the circle, and the amount of decrease increases. .

Wherein, the refractive indices of the respective super-material sheets corresponding to the same vibrator have the same refractive index.

Wherein, the two sides of the metamaterial module are respectively provided with impedance matching films, and each of the impedance matching films comprises a plurality of impedance matching layers.

Wherein, the position of each of the refractive index distribution areas facing the center of the corresponding vibrator is taken as an origin, and the line perpendicular to the super-material sheet layer is the X-axis, and the line parallel to the super-material sheet layer is established as the y-axis. In a Cartesian coordinate system, the refractive index of each refractive index circle is as follows: where is the distance from the vibrator to the metamaterial sheet; d is the thickness of the supermaterial sheet, d = , ―',

^max ^min

"Dish and" _min respectively represent the maximum and minimum values of the refractive index that can be obtained in each refractive index distribution region; R represents the maximum value that can be obtained in the refractive index distribution region y

Wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units, and each of the metamaterial units is attached with an artificial microstructure having the same topological shape, and the artificial microstructures are arranged in each refractive index distribution area. The geometrical dimensions of the artificial microstructures arranged on the respective concentric elements of the same concentric circle are the same on the multi-concentric supermaterial units with the center of each vibrator centered at the center of each vibrator, arranged in each The geometry of the artificial microstructure on the concentric metamaterial unit decreases in a direction away from the center of the circle.

Wherein, the metamaterial unit has a geometric size equal to one tenth of a wavelength of the incident electromagnetic wave. Wherein, the topography of the artificial structure is the same.

Wherein the artificial microstructure comprises two branches orthogonal to each other, each branch comprising a first metal line and a second metal line parallel to each other and a third metal orthogonal to the first metal line and the second metal line a line, the third metal lines of the two branches being orthogonal to each other.

Wherein, the artificial microstructure is a snowflake shape composed of a wire.

Wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units, and a plurality of concentric circles are formed at a center of each of the metamaterial units in the refractive index distribution region facing the center of the corresponding vibrator, so that Each metamaterial unit in the refractive index distribution region is located on these concentric circles; each metamaterial unit A small hole is formed in it.

Wherein each of the metamaterial units forms one of the small holes, and the small holes on each of the metamaterial units are circular holes of equal depth, when a refractive index of a medium filled in the small holes is greater than a refractive index of the substrate When the diameters of the small holes arranged in the same concentric circles of each refractive index distribution area are the same, the diameters of the small holes arranged on the super-material units of the concentric circles are away from the center of the circle. Reduced.

Wherein each of the metamaterial units forms one of the small holes, and the small holes on each of the metamaterial units are circular holes of equal diameter, when the refractive index of the medium filled in the small holes is larger than the refractive index of the substrate When the pores arranged on the respective concentric elements of the same concentric circle in each refractive index distribution region have the same depth, the depth of the small holes arranged on the superconducting unit of each concentric circle is away from the center of the circle Reduced.

Wherein each of the metamaterial units forms one of the small holes, and the small holes on each of the metamaterial units are circular holes of equal depth, when a refractive index of the medium filled in the small holes is smaller than a refractive index of the substrate When the diameters of the small holes arranged in the same concentric circles of each refractive index distribution area are the same, the diameters of the small holes arranged on the super-material units of the concentric circles are away from the center of the circle. Increase.

Wherein each of the metamaterial units forms one of the small holes, and the small holes on each of the metamaterial units are circular holes of equal diameter, when the refractive index of the medium filled in the small holes is smaller than the refractive index of the substrate When the pores arranged on the respective concentric elements of the same concentric circle in each refractive index distribution region have the same depth, the depth of the small holes arranged on the superconducting unit of each concentric circle is away from the center of the circle Increase.

Wherein, each of the metamaterial units is formed with more than one of the small holes, and the small holes on each of the metamaterial units are circular holes having the same geometrical dimensions, and a refractive index of the medium filled in the small holes is smaller than that of the substrate In the case of the refractive index, the number of small holes arranged in the respective metamaterial units of the same concentric circle is the same, and the number of small holes arranged on the super-material units of the respective concentric circles increases in a direction away from the center of the circle.

Wherein, each of the metamaterial units is formed with more than one of the small holes, and the small holes on each of the metamaterial units are circular holes having the same geometrical dimensions, and a refractive index of the medium filled in the small holes is greater than that of the substrate In the case of the refractive index, the number of small holes arranged on the respective metamaterial units of the same concentric circle is the same, and the number of d and the holes arranged on the super-material units of the respective concentric circles decreases in a direction away from the center of the circle.

Wherein, the small hole is filled with air. Wherein, each of the metamaterial units forms the same number of the small holes, and the small holes on each of the metamaterial units are circular holes of the same geometrical size, arranged in the same concentric circle in each refractive index distribution area. The refractive index of the medium filled in the small holes on each of the metamaterial units is the same, and the refractive index of the medium filled in the small holes arranged on the super-material units of the concentric circles decreases in a direction away from the center of the circle.

Wherein each impedance matching layer is a uniform medium having a single refractive index, and the refractive index of each impedance matching layer changes in a direction close to the metamaterial module from a refractive index close to or equal to that of the air to be close to or equal to The refractive index of the metamaterial sheet closest to the impedance matching film on the metamaterial module.

Wherein, the refractive index of each impedance matching layer, where m represents the total number of layers of the impedance matching film, and i represents the impedance matching layer. The impedance matching layer of the super material module has the serial number m.

The base station antenna of the present invention has the following beneficial effects: controlling the propagation of electromagnetic waves by satisfying a certain rule of the refractive index distribution of each point in the space of the metamaterial module, so that the electromagnetic waves emitted by the vibrator pass through the metamaterial module. The half power bandwidth becomes smaller, and the electromagnetic wave can propagate farther, which improves the directivity and gain of the base station antenna.

In addition, a plurality of small holes are formed on the metamaterial sheet layer of the metamaterial module, and the arrangement of the small holes is made to satisfy a certain rule so as to be formed in the refractive index distribution region facing each of the vibrators a plurality of refractive index circles having a refractive index decreasing and decreasing an increasing amount of distribution, thereby changing an electromagnetic wave propagation path when the electromagnetic wave emitted by the vibrator passes through the metamaterial module, reducing a half power of the base station antenna Bandwidth, increased its directionality and gain, allowing electromagnetic waves to travel farther.

In addition, electromagnetic waves emitted by the vibrator are passed through the metamaterial module by forming a plurality of refractive index circles having a refractive index satisfying the above formula corresponding to a refractive index distribution region of each of the vibrators on the metamaterial sheet layer. It can control the propagation path of electromagnetic waves, reduce the half power bandwidth of the base station antenna, improve its directivity and gain, and allow electromagnetic waves to travel farther.

In addition, a plurality of small holes are formed in the super-material sheet layer, and a plurality of refractive indexes having a refractive index satisfying the above formula are formed by using the small holes arranged in a refractive index distribution region corresponding to each of the vibrators The circle can control the propagation path of the electromagnetic wave when the electromagnetic wave emitted by the vibrator passes through the metamaterial module, reduce the half power bandwidth of the base station antenna, improve the directivity and gain, and allow the electromagnetic wave to propagate farther. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will be implemented. BRIEF DESCRIPTION OF THE DRAWINGS The drawings, which are used in the description or the description of the prior art, are briefly described. It is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art do not make creative work. Further drawings can also be obtained from these drawings.

1 is a schematic structural diagram of a base station antenna of the present invention;

Figure 2 is a plan enlarged view of the antenna module of Figure 1;

Figure 3 is a plan enlarged view of the metamaterial sheet of the metamaterial module of Figure 1;

Figure 4 is an enlarged view of a refractive index distribution area shown in Figure 3;

Figure 5 is a distribution diagram of the artificial microstructure in Figure 4;

Figure 6 is an exemplary diagram of the artificial structure of Figure 5;

Figure 7 is an exploded view of the artificial microstructure of Figure 6.

Figure 8 is a first schematic view showing a small hole in a refractive index distribution region corresponding to one vibrator in the second embodiment;

9 is a schematic diagram showing a distribution of refractive index circles in a refractive index distribution region corresponding to one vibrator; FIG. 10 is a second schematic view showing a small hole in a refractive index distribution region corresponding to one vibrator in the second embodiment;

Figure 11 is a third schematic view showing a small hole in a refractive index distribution region corresponding to one vibrator in the second embodiment;

Figure 12 is a schematic view showing the convergence of electromagnetic waves by a metamaterial sheet module corresponding to one vibrator in the second embodiment;

Figure 13 is a view showing a distribution of refractive index circles in a refractive index distribution region corresponding to one vibrator in the third embodiment;

Figure 14 is an enlarged cross-sectional view showing a refractive index distribution region corresponding to one vibrator on a metamaterial sheet layer in the third embodiment;

15 is a schematic view showing the arrangement of a metal wiring structure in a refractive index distribution region corresponding to one vibrator in the third embodiment;

16 is a schematic view showing the convergence of electromagnetic waves when the two sides of the metamaterial module corresponding to one vibrator are respectively covered with the upper impedance matching film in the third embodiment;

Figure 17 is a first plan view showing a small hole in a refractive index distribution region corresponding to one vibrator in the fourth embodiment;

18 is a second arrangement of small holes in a refractive index distribution region corresponding to one vibrator in the fourth embodiment Schematic. The names corresponding to the labels in the figure are:

10 base station antenna, 12 antenna module, 14 backplane, 16 vibrator, 20 metamaterial module, 22 metamaterial sheet, 322, 222, 522 substrate, 223, 323, 423, 523 metamaterial unit, 224, 424 artificial microstructure 226, first metal wire, 227 second metal wire, 228 third metal wire, 28 metal wire structure, 24, 36 refractive index distribution region, 34 refractive index circle, 324, 524 small hole, 30 impedance matching film, 32 Impedance matching layer, specific embodiment

The present invention provides a base station antenna that reduces the half power bandwidth by providing a metamaterial module in the electromagnetic wave emission direction of the array antenna to improve its directivity and gain.

We know that electromagnetic waves are refracted when they are propagating from one homogeneous medium into another, because the refractive indices of the two media are different. For an inhomogeneous medium, the electromagnetic wave is also refracted inside the medium and deflected toward a position where the refractive index is relatively large. The refractive index is equal to ^, that is, the refractive index of the medium depends on its dielectric constant and magnetic permeability.

Metamaterial is an artificial composite material with artificial microstructure as the basic unit and spatial arrangement in a specific way and with special electromagnetic response. People often use the topological shape and geometric size of artificial microstructure to change the points in space. Dielectric constant and magnetic permeability, we can use the topological shape and / or geometric size of the artificial microstructure to modulate the dielectric constant and magnetic permeability of each point in the space, so that the refractive index of each point in the space is some kind Regular changes to control the propagation of electromagnetic waves and apply to applications with special electromagnetic response requirements. Experiments have shown that the larger the geometrical dimensions of the artificial microstructures per unit volume, the larger the dielectric constant of each point in the metamaterial space, and the smaller the dielectric constant. That is, in the case where the topological shape of the artificial microstructure is determined, the dielectric constant can be modulated by satisfying a certain rule of the geometrical size of the artificial microstructure at each point of the metamaterial space, so as to point to the point of the hypermaterial space. The refractive index is discharged to achieve the purpose of changing the propagation path of the electromagnetic wave.

As shown in FIG. 1 and FIG. 2, the base station antenna 10 includes an antenna module 12 and a metamaterial module 20, and the antenna module 12 includes a bottom plate 14 and a vibrator 16 arranged in an array on the bottom plate 14. The figure shows a 4 x 9 array of adjacent rows of vibrators 16 interleaved with each other. In other embodiments, any number of vibrators 16 may be arranged in any manner, such as a matrix arrangement. The metamaterial module 20 includes a plurality of along The metamaterial sheet 22 is formed by superposing the direction perpendicular to the surface of the sheet (that is, the direction of electromagnetic wave emission of the base station antenna). The figure shows three layers. In specific implementation, the number of the super-material sheets 22 can be increased or decreased according to requirements, and an impedance matching layer can be disposed on both sides to reduce electromagnetic wave reflection. Since the refractive index distribution pattern of each of the metamaterial sheets 22 is the same, only one metamaterial sheet 22 is selected as an example below.

As shown in FIG. 3, each metamaterial sheet 22 includes a substrate 222 and a plurality of artificial microstructures 224 attached to the substrate 222. The substrate 222 may be made of a high molecular polymer such as polytetrafluoroethylene or a ceramic material. The artificial microstructure 224 is usually a planar or three-dimensional structure having a certain topography formed by a metal wire such as a copper wire or a silver wire, and is attached to the substrate 222 by a certain processing process, such as etching, plating, and drilling. Engraving, lithography, electron engraving, ion engraving, etc. Since the artificial microstructure 224 is too small, it is approximated as a point in FIG.

Generally, the electromagnetic wave emitted from each of the vibrators 16 can be approximated as a spherical wave, and to be transmitted over a long distance, it needs to be converted into a plane wave. That is, the metamaterial module 20 converts electromagnetic waves in the form of spherical waves into electromagnetic waves in the form of plane waves. Therefore, the refractive index distribution of each point of the super-material sheet layer 22 should satisfy the following rules: a plurality of concentric refractive index circles are formed at a center of the position of each vibrator 16 as a center, and points on the same refractive index circle The refractive index is the same, the refractive index of each refractive index circle decreases along the direction away from the center of the circle, and the amount of decrease increases. 4 The refractive index of the refractive index circle with increasing radius is _ηι , n ₂ , n ₃ .. .n _p , Bay ¹ J has nnn .. !^, JL ( n _p-1 -n _p ) >...> ( n ₂ -n ₃ ) > ( n!-n ₂ ), q is greater than 0 Natural number. Thus, the metamaterial sheet layer 22 forms a refractive index distribution region 24 corresponding to the region of each of the vibrators 16, as shown in Fig. 3 by a plurality of regions separated by broken lines. And the refractive indices of the respective super-material sheets 22 corresponding to the same radius of the same vibrator 16 are the same, and the refractive indices of the respective super-material sheets 22 are the same. As can be seen from the prior art, we can make the topographical shapes of the artificial structures 224 on each of the super-material sheets 22 the same and arranged on the refractive index circle corresponding to the refractive index distribution area 24 of each of the vibrators 16, arranged in the same refraction. The geometrical dimensions of the artificial microstructures 224 at various points on the circle are the same, and the geometry of the artificial microstructures 224 arranged at the points above them decreases in a direction away from the center of the circle. And the geometrical dimensions of the artificial microstructures 224 arranged thereon are the same on the refractive index circles of the respective super-material sheets 22 corresponding to the same radius of the same vibrator 16. In practice, the artificial microstructures 224 should be arranged on a number of concentric circles centered at the center of each vibrator 16 and the geometry of the artificial microstructures 224 arranged at points on the same concentric circle. The dimensions of the artificial microstructures 224 arranged at the respective points are reduced in a direction away from the center of the circle, and the concentric circles of the respective super-material layers 22 corresponding to the same radius of the same vibrator 16 are arranged in the same On The artificial microstructures 224 have the same geometrical dimensions. Thus, the same refractive index circle and the same refractive index arrangement area 24 for each of the vibrators 16 are formed on the respective metamaterial sheets 22.

As shown in FIG. 4, it is an enlarged view of the arrangement of the artificial microstructures 224 selected from one of the vibrators 16 in FIG. In general, we define each artificial microstructure 224 and its attached substrate 222 portion as a metamaterial unit 223, and each metamaterial unit 223 should be less than one-fifth the wavelength of the electromagnetic wave of the desired response. Preferably, the tenth is such that the metamaterial sheet 22 produces a continuous response to electromagnetic waves. Thus, the metamaterial sheet 22 can be considered to be arranged from an array of a plurality of metamaterial units 223. It is known that the size of the metamaterial unit 223 is generally small and can be approximated as a dot, so that the round can be regarded as being stacked by a plurality of metamaterial units 223, so we can Arranging the array of artificial microstructures 224 on the substrate 222 is approximately considered to be arranged on the concentric circles of the artificial structures 224. That is, the artificial microstructure 224 having the largest geometrical dimension is disposed on the metamaterial unit 223 facing the center of the vibrator 16, and the metamaterial unit 223 is further along the distance from the metamaterial unit 223 of the center of the vibrator 16. The artificial microstructure 224 having a reduced geometry is disposed in turn, the geometry of the artificial microstructure 224 at the farthest is the smallest, and the metamaterial unit 223 is at the same distance from the metamaterial unit 223 of the center of the pair of vibrators 16. The artificial microstructures 224 are disposed to have the same geometrical dimensions such that the artificial microstructures 224 conform to the arrangement of concentric circles centered at the center of the vibrator 16 as described above, as indicated by the dashed lines in FIG. . The array arrangement of the artificial microstructures 224 corresponding to one of the vibrators 16 shown in FIGS. 4 and 5 is only an example, and the artificial microstructures 224 are scaled down, in fact, corresponding to the same refractive index distribution law. There are many ways to arrange the artificial microstructures, and we can only reduce the length of the metal wires constituting the artificial microstructures 224 and keep the width of the metal lines constant (that is, the widths of the metal wires are equal). Simplify manufacturing processes

As shown in Figures 6 and 7, an embodiment of the artificial microstructure of the present invention is shown. The artificial microstructure 224 has a snowflake shape and includes two branches 225 orthogonal to each other. Each branch 225 includes a first metal line 226 and a second metal line 227 that are parallel to each other and orthogonal to the first metal line 226. And a third metal line 228 of the second metal line 227. The third metal lines 228 of the two branches 225 of each artificial microstructure 224 are orthogonal to one another.

In this embodiment, the artificial microstructures of the same topography are arranged on the respective metamaterial units according to a certain arrangement rule, thereby modulating the dielectric constant of each super material unit, thereby forming a super material sheet. The specific direction is deflected, so that the electromagnetic wave in the form of a spherical wave can be converted into an electromagnetic wave in the form of a plane wave, so as to be suitable for long-distance transmission, and the refractive index distribution law of the present invention can converge the electromagnetic wave emitted by the vibrator, and the half power bandwidth becomes variable. Small, allowing electromagnetic waves to travel farther, improving the directionality and gain of the base station antenna.

The above-mentioned refractive index distribution law and the relationship of the amount of change thereof can also be realized by the topological shape or the topological shape of the artificial microstructure combined with the geometrical size, or the width of the metal wire constituting the artificial microstructure.

Referring to FIG. 8 and FIG. 9 , the base station antenna according to the second embodiment of the present invention is substantially the same as the base station antenna 10 in the first embodiment, and is different in that it is the second in the present invention. The location of the base station antenna provided by the embodiment corresponding to the artificial microstructure in the base station antenna 10 is an aperture 324. The small holes 324 may be formed on the substrate 322 according to different materials of the substrate 322 by using a suitable process. For example, when the substrate 322 is made of a high molecular polymer, the small holes 324 may be formed on the substrate 322 by a process such as drilling, punching, or injection molding, and when the substrate 322 is made of a ceramic material. When finished, the small holes 324 may be formed on the substrate 322 by drilling, drilling, or high temperature sintering. The refractive index circle 34 is represented by a concentric circle, and the amount of change in the refractive index of the adjacent refractive index circle 34 is represented by the size of the pitch between adjacent concentric circles, and corresponds to the respective refractive indices in the refractive index distribution region 36 of one vibrator. The variation of the refractive index of the circle 34 is as shown in FIG.

It can be seen from the experiment that when the medium filled in the small holes 324 of the respective metamaterial units 323 is the same and the refractive index thereof is smaller than the refractive index of the substrate 322, the larger the volume of the small holes 324 in the entire metamaterial unit 323 is. The smaller the refractive index of the metamaterial unit 323 is; when the medium filled in the small holes 324 of the respective metamaterial units 323 is the same and the refractive index thereof is larger than the refractive index of the substrate 322, the small holes 324 occupy The larger the volume of the entire metamaterial unit 323, the larger the refractive index of the metamaterial unit 323; when the small holes 324 occupy the same volume of the entire metamaterial unit 323, the small holes 324 are filled with different media. The refractive index is proportional to the refractive index of the metamaterial unit 323. The small holes 324 occupying the entire volume of the metamaterial unit 323 can be realized by forming a small hole 324 having a different geometrical size on the metamaterial unit 323, or by forming a plurality of sizes on the metamaterial unit 323. The same aperture 324 is implemented. Below - for explanation.

As shown in FIG. 8, it is a schematic diagram of the arrangement of the small holes 324 in the refractive index distribution area 36 of one vibrator. It can be seen from the principle that the super-material changes the electromagnetic wave propagation path, we can form a plurality of concentric circles on the super-material sheet layer at a position facing the center of each vibrator, so that the respective meta-material units 323 are arranged in these. Concentric circles. Let the small holes 324 arranged on the respective metamaterial units 323 of the same concentric circle The depth and diameter are the same, and the diameter of the small holes 324 arranged on the respective concentric circular metamaterial units 323 increases in a direction away from the center of the circle and the depth does not change. The refractive index distribution region 36 can be formed from the concentric circles on the metamaterial sheet. Since the small holes 324 on the concentric circles of different diameters together with the corresponding portions of the substrate 322 characterize different dielectric constants and magnetic permeability, a refractive index reduction corresponding to each of the vibrators is formed on the metamaterial sheets. A plurality of refractive index circles that are small and reduce the distribution law of an increased amount. As can be seen from the prior art, each of the metamaterial sheets can be regarded as being arranged by a plurality of metamaterial units 323, and each of the metamaterial units 323 is generally small in size and can be approximated as a point, and the round can be It is considered to be formed by stacking a plurality of metamaterial units 323 along the circumference. Therefore, in Figure 8, the array of apertures 324 can be approximated as being arranged along concentric circles.

In other embodiments, the apertures 324 having the same diameter may also be arranged on a plurality of concentric circles centered at a position facing the center of each of the vibrators, as the diameter of the concentric circles increases. The dielectric constant and the magnetic permeability are modulated only by adjusting the depth of the small hole 324, so that different refractive indices are formed on concentric circles of different diameters, thereby forming a distribution having a refractive index decrease and an increase in the decrease amount. Regular multiple refractive index circles.

In addition, we can also form a circular hole having the same geometrical size (i.e., equal in diameter and depth) in a metamaterial unit 323, and adjust the refractive index of each of the circular holes formed in each of the metamaterial units 323. As shown in Figure 10. The number distribution of the small holes 324 on the respective metamaterial units 323 in the refractive index distribution region 36 of each of the vibrating layers on the metamaterial sheet is: arranging the small holes 324 in the refractive index distribution In the super-material unit 323 of the plurality of concentric circles which are centered on the center of the corresponding vibrator in the region 36, the number of the small holes 324 arranged on the respective metamaterial units 323 of the same concentric circle is the same, and is arranged in each concentric The number of apertures 324 in the round metamaterial unit 323 increases in a direction away from the center of the circle. Thus, a plurality of refractive index circles having a distribution law in which the refractive index is decreased and the amount of decrease is increased can also be formed in the refractive index distribution region 36 of the corresponding vibrator. Since more than one circular hole having the same geometrical size is formed on each of the metamaterial units 323, the process of forming the small holes 324 on the substrate 322 can be simplified.

In some of the embodiments described above, the small holes 324 are filled with air, and the refractive index thereof is certainly smaller than the refractive index of the substrate 322. In fact, the small holes 324 may also be filled with a medium having a refractive index greater than that of the substrate 322. For the case shown in FIG. 10, the refractive index distribution of each of the vibrating layers corresponds to each of the vibrators. The number distribution of the small holes 324 in each of the metamaterial units 323 in the region 36 is such that the small holes 324 are arranged in the refractive index distribution region 36 to face the corresponding vibrations. On the plurality of concentric metamaterial units 323 whose center is the center of the circle, the number of the small holes 324 arranged on the respective metamaterial units 323 of the same concentric circle is the same, and is arranged on the super-material units 323 of the respective concentric circles. The number of apertures 324 decreases in a direction away from the center of the circle.

As shown in Fig. 11, a filling pattern of media having different refractive indices filled in respective small holes 324 of the same size in the refractive index distribution region 36 corresponding to one vibrator on the metamaterial sheet. Therefore, the filling rule of the medium of different refractive indexes in the small hole 324 is as follows: a plurality of small holes having the same geometrical arrangement are arranged on the plurality of concentric material super-material units 323 formed at a center of the center of the vibrator. 324, the medium filled in the small holes 324 arranged on the respective metamaterial units 323 of the same concentric circle has the same refractive index, and the refraction of the medium filled in the small holes 324 arranged on the concentric material super-material units 323. The rate decreases in a direction away from the center of the circle. If the size of the refractive index of the medium filled in the small holes 324 is indicated by the density of the hatching, the medium distribution of the different refractive indexes filled in the respective small holes 324 in the refractive index distribution area 36 of one vibrator is as shown in the figure. 11 stated. In Fig. 11, only one of the small holes 324 is formed in each of the metamaterial units 323. In other embodiments, a plurality of the same or different apertures 324 may be formed on each of the metamaterial units 323 as long as the volumes of the apertures 324 on each of the metamaterial units 323 are equal.

And then stacking a plurality of the super-material sheets together, so that each of the super-material sheets forms the same refractive index distribution area 36 corresponding to the same vibrator, and the same vibrator has the same diameter on each of the super-material sheets The refractive index circle 34 has the same refractive index.

As shown in Fig. 12, when the electromagnetic wave in the form of a spherical wave passes through the super material module 20 corresponding to one vibrator 16 of the present invention, each of the supermaterial sheets 22 converges and transforms into a schematic diagram of electromagnetic wave emission in the form of a plane wave. It can be seen that the dielectric of each metamaterial unit 323 is modulated by forming small holes 324 having a certain arrangement regularity on the respective metamaterial sheets 22 of the metamaterial module 20 or filling the same or different medium in the small holes 324. a constant value and a magnetic permeability, and further a refractive index circle 24 having a refractive index decrease and a reduced amount of distribution is formed on the metamaterial sheet 22, so that the electromagnetic wave is deflected in a specific direction, thereby allowing the spherical wave The form of electromagnetic waves converges and transforms into electromagnetic waves in the form of plane waves, which reduces the half power bandwidth of the base station antenna, reduces its directivity and gain, and allows electromagnetic waves to travel farther. The desired refractive index profile of layer 22. The aperture 224 can also be a hole of any shape.

Referring to FIG. 13 and FIG. 14 , the base station antenna according to the third embodiment of the present invention is substantially the same as the base station antenna 10 in the first embodiment, and the difference is that each of the The refractive index of the refractive index circle 24 in each of the refractive index distribution regions 26 on the metamaterial sheet satisfies a formula of a distribution law.

Referring to FIG. 14, a cross-sectional enlarged view of a refractive index distribution region 26 of a vibrator 16 on a layer of metamaterial sheet 22. We take the position of the super-material sheet 22 facing the center of each vibrator 16 as the origin, and the line perpendicular to the super-material sheet 22 as the X-axis, parallel to the super-material sheet 22 Establishing a Cartesian coordinate system for the y-axis, then refraction for each of the vibrators 16 on the meta-material layer 22

Where / is the distance from the vibrating 16 to the surface of the metamaterial sheet 22; d is the thickness of the metamaterial sheet 22, JLd = ^ ^{/2 + ?2} - , "Dish and" 匪 denote Included in the refractive index distribution region 26

^max ^min

The maximum and minimum values of the obtained refractive index; R represents the maximum value y which can be obtained in the refractive index distribution region 26.

We use the origin of the Cartesian coordinate system as the center of the circle and the radius of y as a circle to form a refractive index circle having the same refractive index at each point in the refractive index distribution region 26.

When the metamaterial module 20 is formed, the respective super-material sheets 22 are superposed on the X-axis, so that the same vibrators 16 form the same refractive index distribution region 26 on the respective super-material sheets 22, and The refractive index circles 24 of the respective super-material sheets 22 corresponding to the same radius of the same vibrator 16 have the same refractive index.

Based on the principle of the effect of the artificial microstructure on the refractive index of the metamaterial, we illustrate below how to attach a planar metal trace structure 28 to the substrate 422 of each metamaterial sheet 22 (only one type of artificial microstructure 224) ) to achieve the law of the aforementioned refractive index distribution formula. FIG. 15 is a schematic view showing a layout of the metal wiring structure 28 in the refractive index distribution region 26 corresponding to one of the vibrators 16. The metal wiring structure 28 has a snowflake shape and is scaled down from the inside to the outside. . In fact, there are many ways in which the metal trace structures 28 are arranged, and we can make the widths of the metal lines constituting the metal trace structure 28 equal, which simplifies the manufacturing process.

Since the air is different from the refractive index of the metamaterial module 20, the electromagnetic wave is incident on and out of the metamaterial module 20, and at this time, we usually provide an impedance matching film on both sides of the metamaterial module 20 to reduce electromagnetic waves. reflection. As shown in FIG. 16, the metamaterial module 20 forms an impedance matching film 30 on each side of a portion of a vibrator 16. Each impedance matching film 30 includes a plurality of impedance matching layers 32 pressed together, each impedance matching. Layer 32 is a uniform medium having a single refractive index, Each of the impedance matching layers 32 has a different refractive index, and in a direction close to the metamaterial module 20, its refractive index changes from a refractive index close to or equal to that of air to be close to or equal to the closest of the metamaterial module 20. The refractive index of the metamaterial sheet 22 of the impedance matching film 30. The refractive indices of the respective impedance matching layers 32 satisfy the following formula:

n (0 = ((H ) / 2 ( 2 ) where m represents the total number of layers of the impedance matching film 30 on the side of the metamaterial module 20, and i represents the number of the impedance matching layer 32, closest to the super The number of the impedance matching layer 32 of the material module 20 is m. From the formula (2), the total number m of the impedance matching layer 32 and the maximum refractive index of the metamaterial layer 22 of the metamaterial module 20 are The minimum refractive index has a direct relationship; when i = 1, the formula (2) represents the refractive index of the impedance matching layer 32 in contact with air, which should be close to or equal to the refractive index of the air, visible as long as "and" _{mm is} determined , the total number of layers of the impedance matching layer 32 can be determined.

The structure of each of the impedance matching layers 32 is similar to that of the metamaterial sheet 22, including a substrate and an artificial microstructure attached to the substrate, respectively, by modulating the geometrical dimensions and/or top shapes of the artificial microstructures. The refractive index of the impedance matching layer 32 meets the desired requirements to achieve matching from air to the metamaterial sheet 22. Of course, the impedance matching film 30 may be made of a plurality of natural materials having a single refractive index existing in nature.

When the impedance matching film 30 is disposed on both sides of the metamaterial module 20, I in the formula (1) is the distance of the vibrator 16 to the surface of the impedance matching film 30 closest thereto.

Referring to FIG. 17 and FIG. 18, the base station antenna according to the fourth embodiment of the present invention is substantially the same as the base station antenna in the third embodiment, and is different in that it is the second implementation of the present invention. The location of the base station antenna corresponding to the artificial microstructure in the base station antenna is the aperture 524

As shown in Fig. 17, we form a plurality of concentric circles on the metamaterial sheet with the center of each vibrator centered so that each metamaterial unit 523 is located substantially on these concentric circles. The lengths and diameters of the small holes 524 arranged on the respective metamaterial units 523 of the same concentric circle are the same, and the diameter of the small holes 524 arranged on the respective concentric circular metamaterial units 523 increases in a direction away from the center of the circle. The length does not change. Since the apertures 524 on concentric circles of different diameters together with the corresponding portions of the substrate 522 characterize different dielectric constants and magnetic permeability, a refractive index reduction corresponding to each of the vibrators is formed on the metamaterial sheet. a plurality of refractive index circles that are small and reduce an increasing amount of distribution, and the refractive index distribution region 26 is formed on the metamaterial sheet by a plurality of concentric refractive index circles In other embodiments, the apertures 524 having the same diameter may also be arranged on a plurality of concentric circles centered at a position facing the center of each of the vibrators, as the diameter of the concentric circles increases. The dielectric constant and the magnetic permeability are modulated only by adjusting the length of the small hole 524, so that different refractive indices are formed on concentric circles of different diameters, thereby forming a distribution having a refractive index decrease and an decrease in the amount of decrease. Regular multiple refractive index circles.

Alternatively, we can form a circular hole of the same geometry (i.e., equal in diameter and length) in a metamaterial unit 523, and adjust the refractive index by the number of circular holes formed in each of the metamaterial units 523. As shown in FIG. 18, the number distribution of the small holes 224 on the respective metamaterial units 223 in the refractive index distribution region 26 of each of the vibrating layers 22 is: the small holes 224 are arranged. The number of apertures 524 disposed on the respective concentric units 523 of the same concentric circle on a plurality of concentric circular metamaterial units 523 located within the refractive index distribution region 26 centered on the center of the respective vibrator Similarly, the number of apertures 524 arranged in each concentric circular metamaterial unit 523 increases in a direction away from the center of the circle. Thus, a plurality of refractive index circles having a distribution law of decreasing refractive index and increasing amount of decrease can also be formed in the refractive index distribution region 26 of the corresponding vibrator. Since more than one circular hole having the same geometrical size is formed on each of the metamaterial units 523, the process of forming the small holes 524 on the substrate 522 can be simplified.

In the above several embodiments, the small holes 524 are filled with air, and the refractive index thereof is certainly smaller than the refractive index of the substrate 522. In fact, the apertures 524 may also be filled with a medium having a refractive index greater than the refractive index of the substrate 522. The refractive index distribution law required for the layer. The aperture 524 can also be a hole of any shape.

The above description is only a plurality of specific embodiments and/or embodiments of the invention, and should not be construed as limiting the invention. Numerous modifications and adaptations may be made by those skilled in the art without departing from the basic idea of the invention, and such improvements and modifications are also considered to be within the scope of the invention. For example, the above refractive index distribution law and its variation relationship can also be realized by the topography or topography of the metal wiring structure 28 combined with the geometric size.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the specific embodiments described above, and the specific embodiments described above are merely illustrative and not restrictive, and those skilled in the art In the light of the present invention, many forms may be made without departing from the spirit and scope of the invention as claimed.

Claims

Rights request

A base station antenna, comprising: an antenna module having a plurality of vibrators arranged in an array; and a metamaterial module disposed opposite to the vibrators, the metamaterial module comprising at least one metamaterial sheet, each super The material layer forms a refractive index distribution region corresponding to each of the vibrators, and each of the refractive index distribution regions forms a plurality of concentric refractive index circles at a center of a position facing the center of the corresponding vibrator, and the refraction of each point on the same refractive index circle At the same rate, the refractive index of each refractive index circle decreases in a direction away from the center of the circle, and the amount of decrease increases.

The base station antenna according to claim 1, wherein each of the metamaterial sheets has the same refractive index on each of the super-material sheets having the same radius of the same vibrator.

The base station antenna according to claim 1, wherein two sides of the meta-material module are respectively provided with impedance matching films, and each impedance matching film comprises a plurality of impedance matching layers.

The base station antenna according to claim 1, wherein a position facing a center of the corresponding vibrator in each refractive index distribution region is an origin, and a straight line perpendicular to the super-material sheet layer is an X-axis, A straight line coordinate system is established parallel to the line of the metamaterial sheet for the y-axis, and the refractive index of each index circle is as follows:

Where is the distance from the vibrator to the metamaterial sheet; d is the thickness of the metamaterial sheet, d = ' ―',

^max ^min and " _min represent the maximum and minimum values of the refractive index that can be obtained in each refractive index distribution region, respectively; R represents the maximum value that can be obtained in the refractive index distribution region y

The base station antenna according to any one of claims 1 to 4, wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units, and each of the metamaterial units is attached with an artificial of the same top shape. a microstructure, wherein the artificial microstructures are arranged on a plurality of concentric circular metamaterial units located in a center of each refractive index distribution centered at a position facing the center of each vibrator, arranged in the same concentric circle The geometry of the artificial microstructures on each metamaterial unit is the same, and the geometry of the artificial microstructures arranged on the superconducting elements of each concentric circle decreases in a direction away from the center of the circle.

The base station antenna according to claim 5, wherein the metamaterial unit has a geometry equal to one tenth of a wavelength of an incident electromagnetic wave.

The base station antenna according to claim 5, wherein the topography of the artificial microstructure is the same.

8. The base station antenna according to claim 5, wherein the artificial microstructure comprises a phase Two mutually orthogonal branches, each of which includes a first metal line and a second metal line that are parallel to each other and a third metal line that is orthogonal to the first metal line and the second metal line, the two branches The three metal wires are orthogonal to each other.

The base station antenna according to claim 5, wherein the artificial microstructure is a snowflake shape composed of a metal wire.

The base station antenna according to any one of claims 3 to 3, wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units, and each of the refractive index distribution regions is opposite to a center of the corresponding vibrator. The metamaterial unit in which the position is located forms a plurality of concentric circles at the center of the circle, and the respective metamaterial units in the refractive index distribution region are respectively located on the concentric circles; each of the metamaterial units is formed with small holes.

11. The base station antenna according to claim 10, wherein one of the small holes is formed in each of the metamaterial units, and the small holes on the respective metamaterial units are circular holes of equal depth, when the small holes When the refractive index of the inner filled medium is greater than the refractive index of the substrate, the small holes on the respective metamaterial units of the same concentric circle arranged in each refractive index distribution region have the same diameter and are arranged in respective concentric circles. The diameter of the aperture in the metamaterial unit decreases in a direction away from the center of the circle.

12. The base station antenna according to claim 10, wherein one of the small holes is formed in each of the metamaterial units, and the small holes on the respective metamaterial units are circular holes of equal diameter, when the small holes are When the refractive index of the inner filled medium is greater than the refractive index of the substrate, the small holes on the respective metamaterial units of the same concentric circle arranged in each refractive index distribution region have the same depth and are arranged in respective concentric circles. The depth of the apertures in the metamaterial unit decreases in a direction away from the center of the circle.

13. The base station antenna according to claim 10, wherein one of the small holes is formed in each of the metamaterial units, and the small holes on the respective metamaterial units are circular holes of equal depth, when the small holes When the refractive index of the inner filled medium is smaller than the refractive index of the substrate, the diameters of the small holes arranged in the respective concentric units of the same concentric circle in each refractive index distribution area are the same, and are arranged in the respective concentric circles. The diameter of the small hole in the metamaterial unit increases in a direction away from the center of the circle.

14. The base station antenna according to claim 10, wherein one of the small holes is formed in each of the metamaterial units, and the small holes on the respective metamaterial units are circular holes of equal diameter, when the small holes When the refractive index of the inner filled medium is smaller than the refractive index of the substrate, the small holes on the respective metamaterial units of the same concentric circle arranged in each refractive index distribution region have the same depth and are arranged in respective concentric circles. The depth of d, the hole on the metamaterial unit increases in a direction away from the center of the circle.

15. The base station antenna according to claim 10, wherein each metamaterial unit is shaped One or more of the small holes, and the small holes on the respective metamaterial units are circular holes having the same geometrical size, and when the refractive index of the medium filled in the small holes is smaller than the refractive index of the substrate, they are arranged in the same The number of small holes in each of the super-material units of the concentric circles is the same, and the number of small holes arranged on the super-material units of the respective concentric circles increases in a direction away from the center of the circle.

16. The base station antenna according to claim 10, wherein one or more of the small holes are formed in each metamaterial unit, and the small holes on each of the metamaterial units are circular holes having the same geometrical dimensions. When the refractive index of the medium filled in the small hole is larger than the refractive index of the substrate, the number of small holes arranged on the respective metamaterial units of the same concentric circle is the same, and is arranged on the super-material unit of each concentric circle. The number of holes decreases in a direction away from the center of the circle.

The base station antenna according to any one of claims 14 to 16, wherein the small hole is filled with air.

The base station antenna according to claim 10, wherein each of the metamaterial units forms the same number of the small holes, and the small holes on each of the metamaterial units are circular holes of the same geometrical size, The medium filled in the small holes on the respective metamaterial units of the same concentric circle in each refractive index distribution region has the same refractive index, and the medium filled in the small holes arranged on each concentric circular metamaterial unit The refractive index decreases in a direction away from the center of the circle.

19. The base station antenna according to claim 10, wherein each impedance matching layer is a uniform hook medium having a single refractive index, and the refractive index of each impedance matching layer is close to the direction of the metamaterial module. The refractive index at or equal to the air changes to be close to or equal to the refractive index of the metamaterial sheet closest to the impedance matching film on the metamaterial module.

20. The base station antenna according to claim 10, wherein a refractive index n(i) = ( _max + « _mm )/2 of each impedance matching layer, where m represents a total number of layers of the impedance matching film , i denotes the serial number of the impedance matching layer, and the sequence of the impedance matching layer closest to the metamaterial module is m.