WO2013029324A1

WO2013029324A1 - Base station antenna

Info

Publication number: WO2013029324A1
Application number: PCT/CN2011/084550
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: 2011-08-31
Filing date: 2011-12-23
Publication date: 2013-03-07
Also published as: CN102480047A; CN102480047B

Abstract

The present invention relates to a base station antenna comprising an antenna module having multiple resonators arranged in an array and a metamaterial module arranged in correspondence to the resonators. The metamaterial module comprises at least one metamaterial lamella. Areas on each metamaterial lamella directly opposite to each resonator form refractive index distribution areas. Each refractive index distribution area forms therein multiple refractive index straight lines parallel to each other. With one refractive index straight line within each refractive index distribution area as a dividing line, respectively formed on two sides of the dividing line is one square area. Points on a same refractive index straight line within each square area have identical refractive indexes. Each refractive index straight line decreases gradually along the direction away from the dividing line, while the rate of decrease increases gradually. This changes a transmission path of an electromagnetic wave emitted by the resonators, thus improving the directionality and gain thereof.

Description

Base station antenna

The present application claims priority to Chinese Patent Application Serial No. 2011. 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 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, in a plane containing the maximum radiation direction of the main lobe, the angle between the two points of the 4 bar relative to the maximum radiation direction power flux density is reduced to half (or less than the maximum value of 3 dB). Power angle. In the field strength pattern, the angle at which the field strength of the 4 bar relative to the maximum radiation direction drops 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. 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 plane half power bandwidth. The smaller the half-power bandwidth of the vertical plane, the larger the gain of the base station antenna, 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 and a metamaterial module corresponding to the vibrators, wherein the metamaterial module comprises at least one metamaterial sheet, and each of the metamaterial sheets forms a plurality of mutual Parallel refractive index straight line; with one refractive index line as a boundary line, each of the metamaterial sheets is formed on each side of the boundary line by a plurality of adjacent refractive index lines as a plurality of refractive index distribution regions; The refractive index of each point on the same refractive index line in each refractive index distribution region is the same, and the refractive index of each refractive index straight line decreases in a direction away from the boundary line, and the amount of decrease increases, and each fold The refractive index of the refractive index line closest to the boundary line in the transmittance distribution region is equal, and the refractive index of the refractive index line farthest from the boundary line is equal.

Wherein, the boundary line of each super-material layer is the X-axis, a point on the boundary line is the origin 0, and a line perpendicular to the X-axis and parallel to the meta-material layer and passing through the origin 为 is established as the y-axis. The Cartesian coordinate system O-xy , the refractive index of the linear coordinate of the coordinate y:

Wherein, the distance from the vibrator to the metamaterial sheet; λ is the wavelength of the incident electromagnetic wave; d is the thickness of the metamaterial sheet, and the "dish and the dish" respectively represent the maximum on the metamaterial sheet The refractive index and the minimum refractive index; ^λ , k represents a sequence number in which the refractive index distribution region is changed by a direction in which the X axial distance is further, and is a downward rounding function.

Wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; a plurality of mutually parallel straight lines are formed on each of the super material sheets, so that the respective metamaterial units of the metamaterial sheets are respectively located at the straight On both sides of the boundary line, a plurality of refractive index distribution regions are formed by a group of metamaterial units on a plurality of adjacent straight lines on each side of the boundary line; and each metamaterial unit of each super material sheet layer is attached An artificial microstructure having the same topological shape, the geometrical dimensions of the artificial microstructures arranged on the respective metamaterial units of the same straight line in each refractive index distribution region are the same, and the metamaterial units located in the respective straight lines The geometrical dimensions of the artificial microstructures arranged above are reduced in a direction away from the boundary line, and the respective refractive index distribution regions are arranged on respective metamaterial units of a line closest to the boundary line The geometrical dimensions of the artificial microstructures are all equal, and the geometrical dimensions of the artificial microstructures arranged on the respective metamaterial units of the line furthest from the boundary line are equal.

Wherein, the metamaterial unit has a geometry smaller than one fifth of a wavelength of the incident electromagnetic wave. Wherein, the metamaterial unit has a geometric size equal to one tenth of a wavelength of the incident electromagnetic wave. The artificial microstructure is a planar or three-dimensional structure having a certain topography formed by metal wires.

Wherein, the artificial microstructure is made of copper wire.

Wherein, the artificial microstructure is made of silver wire.

Wherein, the artificial microstructure is made by any one of etching, electroplating, drilling, photolithography, electron engraving and ion engraving. Wherein, the artificial microstructure is in the shape of a snowflake.

Wherein, the artificial microstructure is a planar metal microstructure in the form of a snowflake.

Wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; a plurality of mutually parallel straight lines are formed on each of the super material sheets, so that the respective metamaterial units of the metamaterial sheets are respectively located at the straight On both sides of the dividing line, a plurality of refractive index distribution regions are formed by a group of metamaterial units on a plurality of adjacent straight lines on each side of the dividing line; each metamaterial unit of each metamaterial sheet layer is Forming circular holes of the same depth, the diameters of the small holes formed on the respective metamaterial units of the same straight line in each refractive index distribution region are the same, and are formed on the super-material units of the respective straight lines The diameter of the small holes increases in a direction away from the boundary line, and the small holes formed in the respective metamaterial units in the respective refractive index distribution regions located on the line closest to the boundary line are equal in diameter and located The diameters of the small holes formed on the respective metamaterial units of the straight line farthest from the boundary line are equal.

Wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; a plurality of mutually parallel straight lines are formed on each of the metamaterial sheets, and the respective metamaterial units of the metamaterial sheets are respectively located at the straight lines Separating each metamaterial unit of the metamaterial sheet on both sides of the boundary line with a straight line as a boundary line, and metamaterials on several adjacent straight lines on each side of the boundary line The unit forms a plurality of refractive index distribution regions in a group; each of the metamaterial layers of each metamaterial sheet forms circular apertures having the same diameter, so that each of the same straight lines located in each refractive index distribution region The depths of the small holes formed on the material unit are all the same, and the depth of the small holes formed on the super-material units of the respective straight lines increases in a direction away from the boundary line, and the respective refractive index distribution areas are located away from each other. The small holes formed on the respective metamaterial units of the closest line of the boundary line are all equal in depth, and the small holes formed on the respective metamaterial units of the straight line farthest from the boundary line The depths of the holes are all equal.

Wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; a plurality of mutually parallel straight lines are formed on each of the super material sheets, so that the respective metamaterial units of the metamaterial sheets are respectively located at the straight On both sides of the dividing line, a plurality of refractive index distribution regions are formed by a group of metamaterial units on a plurality of adjacent straight lines on each side of the dividing line; each metamaterial unit of each metamaterial sheet layer is Forming a plurality of circular apertures having the same diameter and depth, the number of the small holes formed on the respective metamaterial units of the same straight line in each refractive index distribution region is the same, located in each straight line The number of the small holes formed on the metamaterial unit increases in a direction away from the boundary line, and each refractive index distribution The number of the small holes formed in each of the metamaterial units located in the straight line closest to the boundary line in the region is equal, and the small holes formed on the respective metamaterial units of the straight line farthest from the boundary line The number is equal.

Wherein, the small hole is filled with a medium.

Wherein, the small hole is filled with air.

Wherein, a straight line passing through the origin 0 and perpendicular to the xoy coordinate plane is the z-axis, thereby establishing a Cartesian coordinate system 0-xyz, and the meta-material module includes a plurality of super-material layers superposed along the z-axis, each super-material layer The same refractive index distribution region is formed on both sides with the X-axis as the boundary line.

Wherein, the linear distributions of the refractive indices in the respective refractive index distribution regions of the respective super-material sheets are the same. Wherein, at least one side of the meta-material module is provided with an impedance matching film, each impedance matching film comprises a plurality of impedance matching layers, each impedance matching layer is a uniform medium having a single refractive index, and a refractive index of each impedance matching layer In a direction proximate to the metamaterial module, the refractive index is approximately changed from or equal to that of air to a level close to or equal to the refractive index of the metamaterial sheet closest to the impedance matching film on the metamaterial module.丄

Wherein, the refractive index of each impedance matching layer: ⁿ (0 = (("+" _min V ² ) ^m , where _m represents the total number of layers of each impedance matching film, i represents the serial number of the impedance matching layer, The sequence of the impedance matching layer adjacent to the metamaterial module is m.

The base station antenna of the present invention has the following beneficial effects: by forming a plurality of refractive index distribution regions corresponding to each of the vibrating layers on the metamaterial sheet, a plurality of mutually parallel refractive index straight lines are formed in each refractive index distribution region, One of the refractive index lines is a boundary line and the refractive indices are linearly separated in two square regions on both sides of the boundary line, and in each square region, the distance from the refractive index line increases linearly from the boundary line The refractive index is decreased and the amount of decrease is increased, so that the electromagnetic wave emitted by the vibrator is deflected in the direction of the large refractive index when passing through the metamaterial sheet of the metamaterial module, thereby changing the propagation path of the electromagnetic wave. The half power bandwidth of the base station antenna is reduced, the directivity and gain are improved, and electromagnetic waves are transmitted farther. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only Some embodiments of the present invention, for those of ordinary skill in the art, do not pay Other drawings can also be obtained from these drawings on the premise of inventive labor.

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

Figure 2 is an enlarged front elevational view of the antenna module of Figure 1;

3 is a schematic view of a metamaterial sheet of the metamaterial module of FIG. 1 when a Cartesian coordinate system O-xyz is established;

4 is an enlarged front elevational view of the metamaterial sheet of FIG. 3 separated into a plurality of refractive index distribution regions based on the established Cartesian coordinate system O-xyz;

Figure 5 is a view showing a refractive index distribution corresponding to a straight line of refractive index in a plurality of refractive index distribution regions shown in Figure 4;

6 is a schematic view showing the arrangement of the artificial microstructure formed on the partial metamaterial sheet layer corresponding to the refractive index line of FIG. 5;

7 is a schematic view showing the arrangement of the apertures formed on the partial metamaterial sheet layer corresponding to the refractive index line of FIG. 5;

Figure 8 is a schematic view showing another arrangement of the apertures formed on the partial metamaterial sheet layer corresponding to the refractive index line of Figure 5;

Fig. 9 is a schematic view showing the structure of a super-material module of the present invention which is covered with an impedance matching film on both sides. The names corresponding to the labels in the figure are:

10 base station antenna, 12 antenna module, 14 base plate, 16 vibrator, 20 metamaterial module, 22, 32 metamaterial sheet, 222, 322 substrate, 223, 323 metamaterial unit, 224 artificial microstructure, 24, 34 refractive index distribution Zone, 26, 36 straight line, 324 small hole, 40 impedance matching thin moon 筻, 42 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 transmitting or receiving direction of the antenna to improve its directivity and gain.

We know that electromagnetic waves refract when propagating from a homogeneous medium into another homogeneous medium due to the different refractive indices of the two media. For a non-uniform medium, electromagnetic waves are 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 with special electromagnetic response. Generally, the metamaterial includes a plurality of metamaterial sheets, each of which is composed of an artificial microstructure and a substrate for attaching an artificial microstructure (each artificial microstructure and a portion of the substrate to which it is attached are artificially defined as a metamaterial) Unit), by adjusting the topological shape and geometrical dimensions of the artificial microstructure, the points on the substrate can be changed (that is, each metamaterial unit, since each metamaterial unit should be smaller than one-fifth of the wavelength of the incident electromagnetic wave, preferably It is one tenth, usually very small, so each metamaterial unit can be regarded as a point, the same as the dielectric constant and permeability. Therefore, 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 on the substrate, so that the refractive index of each point on the substrate changes in a certain law, and the electromagnetic wave can be controlled. Propagation and application to applications with special electromagnetic response requirements. Experiments have shown that, in the case where the topography of the artificial microstructure is the same, the larger the geometrical size of the artificial microstructure per unit area, the larger the dielectric constant of each point on the substrate; conversely, the smaller the dielectric constant. That is, in the case where the topological shape of the artificial microstructure is determined, the dielectric constant and the magnetic permeability can be modulated by satisfying a certain rule of the geometrical size of the artificial microstructure at each point on the substrate. When the super-material layers arranged in a certain regularity are superimposed to form a meta-material, the refractive index of each point in the hyper-material space is also distributed in such a manner, and the purpose of changing the propagation path of the electromagnetic wave can be achieved. In addition, we can also create small refractive holes on the substrate to form this refractive index distribution law.

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 arrayed on the bottom plate 14, as shown in the figure. A 4 x 9 array of staggered arrays of adjacent two rows of vibrators 16 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 metamaterial sheets 22 stacked in a direction perpendicular to the surface of the sheet (ie, the electromagnetic wave emitting or receiving direction of the base station antenna), and three super-material layers are shown. 22 The case where the front and back surfaces are directly bonded to each other. In a specific implementation, the number of the super-material sheets 22 can be increased or decreased according to requirements, and the individual super-material layers 22 can also be assembled and assembled at equal intervals. Since the refractive index distributions of the respective super-material sheets 12 are the same, only one super-material sheet 22 is selected as an example below.

A point on the super-material sheet layer 22 is selected as an origin O, and a plane parallel to the surface of the meta-material sheet layer 22 is a xoy coordinate plane, and a straight line passing through the origin 0 and perpendicular to the xoy coordinate plane is a z-axis. The coordinate system is 0-xyz. The super-material sheet layer 22 is formed with a plurality of refractive index distribution regions 24 along the y-axis with the X-axis as a boundary line, and the refractive index of each point having the same y-coordinate in each of the refractive index distribution regions 24 is the same, and The refractive index of each point having a different y coordinate decreases as the distance from the x-axis increases and the amount of decrease increases. For each of the refractive index distribution regions 24, the refractive index of each point having the smallest y coordinate in the refractive index distribution region 24 having a larger y coordinate is larger than the point at which the y coordinate in the adjacent refractive index distribution region 24 having a smaller y coordinate is the largest. Refractive index. Hereinafter, the refractive index of each point where the y-coordinates in the respective refractive index distribution regions 24 on the super-material sheet layer 22 are the smallest and the y-coordinates are the same at the respective points of the y-coordinates are equal (that is, the refractive index changes) The same range of refractive index segmentation law.

In the Cartesian coordinate system O-xyz established above, for each point of the metamaterial layer 22 having the same y coordinate, the refractive index satisfies the following relationship:

_{( x} ² + y ² -i -k

n(y) =

Where Z is the distance from the vibrator 16 to the surface of the metamaterial sheet 22; λ is the wavelength of the incident electromagnetic wave; d is the thickness of the metamaterial sheet 22, d = ^ - ^ , "dish and min" respectively Representing the super material n max - n mi -n

Maximum and minimum refractive indices on the web layer 22; k, k represents the refraction

The rate distribution area 24 is a sequence number that changes from a direction in which the X-axis is farther away, and ^^ is a downward rounding function, that is, the largest integer remaining directly in the fractional part is removed.

It can be seen from the formula (1) that since the refractive indices of the points having the same y-coordinate are the same, a direct linear line can be connected, and the refractive indexes of the points different in the y-coordinate are different, thereby being on the super-material sheet 22 A plurality of mutually parallel refractive index straight lines are formed. On each side of the X-axis, a plurality of mutually connected refractive index distribution regions 24 are formed by a plurality of mutually adjacent adjacent refractive index lines, and the refraction of each point having the smallest y-coordinate in each refractive index distribution region 24 The refractive indices of the points at which the rates are equal and the y-coordinate are the largest are equal, so that a plurality of refractive index straight lines satisfying the aforementioned refractive index distribution law are formed on the meta-material sheet layer 22. At this time, k is a sequence number in which the refractive index distribution region 24 is changed by the origin O in a direction larger than the y-axis.

As an example, we take the position of the super-material sheet 22 substantially facing the center of the antenna module 12 as the origin O of the Cartesian coordinate system O-xyz, and the Cartesian coordinate system O-xyz is in the meta-material layer The position on 22 is as shown in FIG. 3; the linear line of refraction is represented by a plurality of straight lines parallel to the X-axis and separated by a certain distance, and the super-material sheet 22 is on both sides of the X-axis, and two adjacent refractive index straight lines One of the refractive index distribution regions 24 is formed such that the distribution of the refractive index distribution regions 24 on the metamaterial sheet 22 can be represented by Figure 4, which is shown on each side of the X-axis by Figure 4. Three refractive index distribution regions 24 are formed by separating three refractive index lines separated by a certain distance. If we increase the absolute value of the y-coordinate on each side of the X-axis, the three refractive index distribution regions 24 are referred to as first, second, and third refractive indices, respectively. The distribution region 24, and the refractive index of the first refractive index distribution region 24 increases with the absolute value of the y coordinate of the refractive index line, respectively, n _max , n _n , n _lp , n _mm , and the second refractive index distribution region The increase in the absolute value of the y-coordinate of the refractive index line in 24 is the increase in the absolute value of the y-coordinate of the refractive index line in the third refractive index distribution region 24, respectively, and its refractive index is n _max , respectively. , n ₃₁ , ..., n _3n , n _min , then: ^ Lower relation:

n _max > nu > ... > n _lp > n _min ( 2 )

> n ₂₁ > ... > n _2m > ( 3 )

n _max > n ₃ i > . . . > n _3n > n _min ( 4 )

Equations (2), (3), and (4) cannot take equal signs at the same time, and m, n are natural numbers greater than 0. Preferably, p = m = n.

In order to visually represent the refractive index distribution law of the refractive index straight line in the six refractive index distribution regions 24 shown in FIG. 4, we use a plurality of mutually parallel straight lines to express the refractive index straight line, which is represented by a linear dense line. The refractive index of the refractive index is linear, and the denser the refractive index is, the smaller the refractive index is, the smaller the refractive index is, and the refractive index change of each refractive index line on the metamaterial sheet 22 is as shown in FIG. 5.

For a plurality of said metamaterial sheets 22, we have them stacked together along the z-axis, and the same refractive index distribution regions 24 are formed on each of the metamaterial sheets 22, and the respective refractive indices on the respective super-material sheets 22 are The linear distribution of the refractive indices within the distribution region 24 are all the same, thereby forming the metamaterial module 20.

Below we illustrate how the refractive index distribution on each metamaterial sheet 22 satisfies the formula (1) by the arrangement of the artificial microstructures. Referring to FIG. 6, each of the metamaterial sheets 22 includes a substrate 222 and a plurality of artificial structures 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. , lithography, electron engraving, ion engraving, etc. 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 smaller than one-fifth of the wavelength of the incident electromagnetic wave, preferably One tenth, such that the metamaterial sheet 22 produces a continuous response to incident electromagnetic waves. It can be seen that each of the metamaterial sheets 22 can be regarded as being arranged by an array of a plurality of metamaterial units 223, and since the metamaterial unit 223 is very small, it can be approximated as a point, and therefore, arranged in a line The array formed by the plurality of the metamaterial units 223 can be regarded as a straight line formed by dots. Therefore, we can make a plurality of straight lines 26 (shown by chain lines in the figure) parallel to the X-axis, and make the meta-material layer The respective metamaterial units 223 of 22 are respectively located on the straight lines 26; the respective metamaterial units 223 of the metamaterial sheet 22 are separated on both sides of the boundary line by using the straight line 26 as a boundary line, The metamaterial units 223 on a plurality of adjacent straight lines 26 on each side of the fascia line form a plurality of interconnected refractive index distribution regions 24 in a group. The fascinating microstructures 224 having the same topography are attached to the respective metamaterial units 223 of the metamaterial sheet 22, and each of the metamaterial units 223 located in the same line 26 within each of the refractive index distribution regions 24 The geometrical dimensions of the artificial microstructures 224 disposed above are all the same, and the geometry of the artificial microstructures 224 disposed on the metamaterial unit 223 of each of the straight lines 26 decreases in a direction away from the boundary line, and The geometrical dimensions of the artificial microstructures 224 disposed in each of the metamaterial distribution regions 24 located on the respective metamaterial units 223 that are equal in size and located at a line 26 furthest from the boundary line are equal. Thus, since the artificial microstructure 224 on each of the metamaterial units 223 of the different straight lines 26 within each of the refractive index distribution regions 24, together with the corresponding portions of the substrate 222, characterize different dielectric constants and magnetic permeability, and The distance of the straight line 26 where the metamaterial unit 223 is located increases from the boundary line, and the dielectric constant of the metamaterial unit 223 decreases. Thus, a plurality of mutually parallel refractive index straight lines are formed on the metamaterial sheet layer 22, and on each side of the boundary line, a plurality of refractive index distribution regions are formed by a plurality of adjacent refractive index straight lines. 24, in each of the refractive index distribution regions 24, the refractive indices of the adjacent refractive index lines decrease as the distance from the boundary line increases, and the respective refractive index distribution regions 24 are separated from the boundary line. The refractive indices of the most recent refractive index lines are equal, and the refractive indices of the straight line of the refractive index farthest from the boundary line are equal, thereby forming an increase in the refractive index as the distance from the boundary line increases. The law of segmentation or discontinuous distribution. FIG. 6 is only a schematic view of the arrangement of the artificial microstructure 224 on each of the metamaterial units 223 of the portion of the metamaterial sheet 22, wherein the straight lines 26 are symmetrically distributed along the X-axis as a boundary line. On the super-material sheet 22, the artificial microstructure 224 is a planar metal microstructure in the shape of a snowflake and is proportionally reduced in each refractive index distribution region 24 as the distance from the X-axis of the line 26 increases. . In fact, the artificial microstructures 224 are arranged in a variety of ways, and the widths of the lines constituting the artificial microstructures 224 can be made equal, which simplifies the manufacturing process.

In addition, we can also form a refractive index distribution law satisfying the formula (1) by forming small holes in the substrate 222 of the metamaterial sheet layer 22. As shown in FIG. 7, the metamaterial sheet layer 32 includes a substrate 322 and a plurality of small holes 324 formed on the substrate 322. 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 When the high molecular polymer is made, the small hole 324 may be formed on the substrate 322 by drilling, drilling, or injection molding, and may be passed through the drilling machine when the substrate 322 is made of a ceramic material. The hole 324 is formed on the substrate 322 by a process such as drilling, stamping, or high temperature sintering. We also define each aperture 324 and its substrate 322 portion as a metamaterial unit 323, and each metamaterial unit 323 should be less than one-fifth the wavelength of the incident electromagnetic wave.

It can be seen from the experiment that when the medium filled in the small holes 324 is air, the larger the volume of the small holes 324 in the entire metamaterial unit 323, the smaller the refractive index of the metamaterial unit 323. Therefore, as above, we make a plurality of equidistant straight lines 36 (shown by dashed lines in the figure) parallel to the X-axis, so that the respective metamaterial units 323 of the meta-material sheet 32 are located at the straight lines 36, respectively. Separating each metamaterial unit 323 of the metamaterial sheet 32 on both sides of the boundary line with a straight line 36 as a dividing line, by a number of adjacent straight lines 36 on each side of the dividing line The upper metamaterial unit 323 is a set of a plurality of interconnected refractive index distribution regions 34. One of the small holes 324 is formed in each of the metamaterial units 323, and in each of the refractive index distribution regions 34, the depth and diameter of the small holes 324 formed on the respective metamaterial units 323 of the same straight line 36 are The same (ie, the same volume), the diameter of the small holes 324 formed on the metamaterial unit 323 of each straight line 36 increases in a direction away from the boundary line, and the depth does not change; and each of the refractive index distribution areas 34 The small holes 324 formed in the respective metamaterial units 323 of the straight line 36 closest to the boundary line are all equal in diameter, and the plurality of the metamaterial units 323 located on the straight line 36 farthest from the boundary line are formed. The apertures 324 are all equal in diameter. In order to form a plurality of mutually parallel refractive index lines on the metamaterial sheet 32, on each side of the boundary line, a plurality of interconnected refractive index distribution regions are formed by a plurality of adjacent refractive index lines 34. In each of the refractive index distribution regions 34, the refractive indices of the refractive index lines continuously decrease as their distance from the boundary line increases, and the respective refractive index distribution regions 34 are separated from the boundary line. The refractive indices of the most recent refractive index lines are equal, and the refractive indices of the straight line of the refractive index farthest from the boundary line are equal, so that the refractive index decreases as the distance of the refractive index straight line from the boundary line increases. Small and in a segmented or discontinuous distribution. 7 is only a schematic view of the arrangement of the small holes 324 on the respective metamaterial units 323 of the portion of the metamaterial sheet 32, wherein the straight lines 36 are symmetrically distributed on the X-axis as a boundary line. The super material sheet 32 is on.

Similarly, we can also arrange the small holes 324 having the same diameter on the straight lines 36, and increase the distance of the straight line 36 from the X-axis in each of the refractive index distribution regions 34. The depth of the small holes 324 is formed to form a refractive index distribution law satisfying the formula (1), thereby forming a plurality of refractive index variation ranges. The same refractive index distribution region 34 is enclosed. Moreover, the small holes 324 occupying the entire volume of the metamaterial unit 323 can be realized not only by forming the small holes 324 having different geometrical dimensions on the metamaterial unit 323, but also by the super material unit 323. The apertures 324 are formed in equal numbers and geometrically identical or different, as shown in FIG.

When the metamaterial module 20 is formed, each of the metamaterial sheets 22 is superposed on the z-axis, and the arrangement of the artificial structures 244 of each of the super-material sheets 22 is the same, or The super-material sheets 32 are superposed on the z-axis, and the arrangement of the small holes 324 on the meta-material unit 323 of each of the super-material sheets 32 is the same, so that each of the super-material sheets 22 is Or the same refractive index distribution law is formed on 32.

As can be seen from the above, by providing artificial microstructures 224 or small holes 324 having a certain top shape and/or geometrical shape on the respective super-material sheets 22 or 32 of the meta-material module 20 and arranging them according to a certain regularity. The cloth, the dielectric constant and the magnetic permeability of each of the metamaterial units 223 or 323 can be modulated, thereby forming a refractive index distribution law satisfying the formula (1) on each of the super material sheets 22 or 32, that is, forming a plurality of The refractive index distribution region 24 or 34 whose refractive index decreases with increasing distance of the refractive index from the X-axis and the refractive index variation range is the same, so that the electromagnetic wave is deflected in a specific direction, thereby reducing the half power of the base station antenna. The bandwidth becomes smaller, increasing its directivity and gain, allowing electromagnetic waves to travel farther.

In addition, since air is different from the refractive index of the metamaterial module 20, reflection occurs when electromagnetic waves are incident on and exiting the metamaterial module 20. In this case, we usually provide an impedance matching film on both sides of the metamaterial module 20. To reduce electromagnetic wave reflection. As shown in FIG. 9, an impedance matching film 40 is formed on each side of the metamaterial module 20, and each of the impedance matching films 40 includes a plurality of impedance matching layers 42 pressed together, and each impedance matching layer 42 is a uniform medium. Having a single refractive index, each impedance matching layer 42 has a different refractive index, and in a direction close to the metamaterial module 20, the refractive index of each impedance matching layer 42 is gradually changed from a refractive index close to or equal to that of air to The refractive index of the metamaterial sheet 22 or 32 closest to the impedance matching film 40 of the metamaterial module 20 is close to or equal to. The refractive indices of the respective impedance matching layers 42 satisfy the following formula:

n

Where m represents the total number of layers of the impedance matching film 40 on the side of the metamaterial module 20, i represents the number of the impedance matching layer 42, and the sequence of the impedance matching layer 42 closest to the metamaterial module 20 is m from Equation (5) shows that the total number m of layers of each impedance matching layer 42 and the maximum refractive index of the metamaterial layer 22 or 32 of the metamaterial module 20 are directly related to the minimum refractive index 3⁄4n; when i=l When, (5) Representing the refractive index of the impedance matching layer 42 in contact with air, which should be close to or equal to the refractive index of the air, it can be seen that the total number of layers per impedance matching layer 42 can be determined as long as "and" is determined.

Each of the impedance matching layers 42 has a structure similar to that of the metamaterial sheet 22 or 32, and includes a substrate and an artificial microstructure attached to the substrate or a small hole formed on the substrate, by modulating artificial The geometry and/or topography of the microstructures or apertures are such that the refractive index of each of the impedance matching layers 42 meets the desired requirements to achieve a match from air to the metamaterial sheet 22 or 32. Of course, the impedance matching film 40 may be made of a plurality of materials having a single refractive index existing in nature.

When the impedance matching film 40 is separately 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 40 closest thereto.

The refractive index distribution of the formula (1) can also be achieved by the topography or topography of the artificial microstructure 224 or the aperture 324 in combination with the geometrical dimensions, and the apertures 324 can also be filled with refractive indices. The same medium is used to change the refractive index of each metamaterial unit 323.

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 and a meta-material module corresponding to the vibrators, the meta-material module comprising at least one meta-material layer, each super-material layer being formed a plurality of mutually parallel refractive index lines; wherein one of the refractive index lines is a boundary line, and each of the metamaterial sheets is formed by a plurality of adjacent refractive index lines on each side of the boundary line to form a plurality of refractive indexes a distribution area; a refractive index of each point on a straight line of the same refractive index in each refractive index distribution region is the same, and a refractive index of each refractive index line decreases in a direction away from the boundary line, and the amount of decrease increases, each The refractive index of the refractive index line closest to the boundary line in the refractive index distribution region is equal, and the refractive index of the refractive index straight line farthest from the boundary line is equal.

The base station antenna according to claim 1, wherein the boundary line of each metamaterial sheet is an X-axis, a point on the boundary line is an origin 0, and is perpendicular to an X-axis and parallel to The super-material sheet layer establishes a Cartesian coordinate system O-xy for the y-axis through the straight line of the origin O, and the refractive index of the refractive index line of the coordinate y is: where is the distance from the vibrator to the meta-material sheet layer; The wavelength of the incident electromagnetic wave; d is the thickness of the metamaterial sheet, d = ^ - ^, " and "the dish respectively represent the maximum refractive index and the minimum refractive index on the metamaterial sheet; k = y3⁄4 ₀ r ( £^Z !), k represents the refractive index distribution region by the X-axis λ

The sequence number that changes further in the distance, fl ^oor is the rounding down function.

The base station antenna according to claim 1, wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; and a plurality of mutually parallel straight lines are formed on each of the super material sheets. Each of the metamaterial units of the metamaterial sheet layer are respectively located on the straight lines; wherein the plurality of refractive index distribution regions are formed by grouping the metamaterial units on several adjacent straight lines on each side of the line as a boundary line; The artificial microstructures having the same topological shape are attached to the respective metamaterial units of each metamaterial sheet, and the artificial microstructures arranged on the respective metamaterial units of the same straight line in each refractive index distribution region are attached. The geometric dimensions are all the same, the geometrical dimensions of the artificial microstructures arranged on the super-material units of the respective straight lines are reduced in a direction away from the boundary line, and the respective refractive index distribution regions are located closest to the boundary line. The artificial microstructures arranged on the respective metamaterial units of the straight line are equal in geometry, and the artificially arranged on the respective metamaterial units of the straight line farthest from the boundary line Microstructural geometry The inches are equal.

The base station antenna according to claim 3, wherein the metamaterial unit has a geometry smaller than one fifth of a wavelength of an incident electromagnetic wave.

The base station antenna according to claim 4, 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 3, wherein the artificial microstructure is a planar or three-dimensional structure having a certain shape formed by a metal wire.

The base station antenna according to claim 3, wherein the artificial microstructure is made of copper wire.

The base station antenna according to claim 3, wherein the artificial microstructure is made of silver wire.

9. The base station antenna according to claim 3, wherein the artificial microstructure is fabricated by any one of etching, plating, drilling, photolithography, electron engraving, and ion engraving.

10. The base station antenna of claim 3, wherein the artificial microstructure is snowflake shaped.

The base station antenna according to claim 3, wherein the artificial microstructure is a snow-like planar metal microstructure.

12. The base station antenna according to claim 1, wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; and each of the super material sheets is formed with a plurality of mutually parallel straight lines. Each of the metamaterial units of the metamaterial sheet layer are respectively located on the straight lines; wherein the plurality of refractive index distribution regions are formed by grouping the metamaterial units on several adjacent straight lines on each side of the line as a boundary line; Each of the metamaterial layers of each metamaterial sheet forms circular holes of the same depth, and the diameters of the small holes formed on the respective metamaterial units of the same straight line in each refractive index distribution region are Similarly, the 'j, the diameter of the hole formed on each of the straight-line metamaterial units increases in a direction away from the boundary line, and each of the refractive index distribution regions is located at a line closest to the boundary line. The apertures formed in the material unit are all equal in diameter, and the apertures formed on the respective metamaterial units located in the line furthest from the boundary line are equal in diameter.

13. The base station antenna according to claim 1, wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; and a plurality of mutually parallel straight lines are formed on each of the metamaterial sheets. Super Each of the metamaterial units of the material sheet layer are respectively located on the straight lines; and each of the metamaterial units of the metamaterial sheet layer is separated on both sides of the boundary line by a straight line as a boundary line, and the boundary line is located at the boundary line A plurality of metamaterial units on a plurality of adjacent straight lines on each side form a plurality of refractive index distribution regions; each of the metamaterial layers of each metamaterial sheet forms a circular aperture having the same diameter, allowing each to be located The depths of the small holes formed on the respective metamaterial units of the same straight line in the refractive index distribution region are all the same, and the depth of the small holes formed on the metamaterial units of the respective straight lines is away from the boundary line Increasing, and the respective pores formed on the respective metamaterial units in the respective refractive index distribution regions located on the straight line closest to the boundary line are equal in depth, and each of the metamaterials located on the straight line farthest from the boundary line The depths of the apertures formed in the unit are all equal.

The base station antenna according to claim 1, wherein each of the metamaterial sheets is arranged by a plurality of metamaterial units; and a plurality of mutually parallel straight lines are formed on each of the metamaterial sheets. Each of the metamaterial units of the metamaterial sheet layer are respectively located on the straight lines; and each of the metamaterial units of the metamaterial sheet layer is separated on both sides of the boundary line by a straight line as a boundary line, A plurality of metamaterial units on a plurality of adjacent straight lines on each side of the dividing line form a plurality of refractive index distribution regions; each of the metamaterial layers of each metamaterial sheet has an unequal number of diameters and depths a circular aperture, the number of the small holes formed on each of the metamaterial units of the same straight line in each refractive index distribution region being the same, and the small holes formed on the super-material units of the respective straight lines The number increases in a direction away from the boundary line, and the number of the small holes formed in each of the metamaterial units in the respective refractive index distribution regions which are located closest to the boundary line is equal, The number of the small holes formed on the respective metamaterial units located at the farthest line from the boundary line are equal.

The base station antenna according to any one of claims 12 to 14, wherein the small hole is filled with a medium.

The base station antenna according to claim 15, wherein the small hole is filled with air.

The base station antenna according to claim 2, wherein a straight line passing through an origin 0 and perpendicular to a xoy coordinate plane is a z-axis, thereby establishing a Cartesian coordinate system O-xyz, and the meta-material module includes a plurality of edges The z-axis superimposed super-material sheet layer has the same refractive index distribution area on both sides with the X-axis as a boundary line on each of the super-material sheets.

18. The base station antenna according to claim 17, wherein the refractive index linear distributions in the respective refractive index distribution regions of the respective metamaterial sheets are the same.

The base station antenna according to claim 1, wherein at least the metamaterial module An impedance matching film is disposed on one side, each impedance matching film includes a plurality of impedance matching layers, each impedance matching layer is a uniform hook medium having a single refractive index, and the refractive index of each impedance matching layer is adjacent to the metamaterial module The direction is gradually changed from a refractive index close to or equal to air to a value 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 19, wherein a refractive index of each impedance matching layer: n(i) = ((« _max + « _mi J/2)^, where m represents each The total number of layers of the impedance matching film, i represents the serial number of the impedance matching layer, and the sequence of the impedance matching layer closest to the metamaterial module is m.