CN108511925B

CN108511925B - Mirror image 3D MIMO half-wave antenna array and array establishing method

Info

Publication number: CN108511925B
Application number: CN201710109327.6A
Authority: CN
Inventors: 张长清
Original assignee: China Mobile Communications Group Co Ltd; China Mobile Group Henan Co Ltd
Current assignee: China Mobile Communications Group Co Ltd; China Mobile Group Henan Co Ltd
Priority date: 2017-02-27
Filing date: 2017-02-27
Publication date: 2020-11-10
Anticipated expiration: 2037-02-27
Also published as: CN108511925A

Abstract

The embodiment of the invention discloses a mirror image 3D MIMO half-wave antenna array and an array establishing method, wherein the mirror image 3D MIMO half-wave antenna array comprises the following components: the device comprises a 2D MIMO half-wave antenna array and a reflector; the 2D MIMO half-wave antenna array is arranged on the mirror surface side of the reflector; and a virtual image of the 2D MIMO half-wave antenna array in the reflector and the 2D MIMO half-wave antenna array form a mirror image 3D MIMO half-wave antenna array. According to the embodiment of the invention, a mirror is added on the basis of the 2D MIMO half-wave antenna array by adopting a mirror image technology, so that the 2D MIMO half-wave antenna array can generate a virtual image behind the mirror surface of the mirror to form a mirror image 3D MIMO half-wave antenna array, the cost, the technology, the volume and the weight are almost the same as those of the 2D MIMO half-wave antenna array, but the beam forming is far better than that of the 2D MIMO half-wave antenna array.

Description

Mirror image 3D MIMO half-wave antenna array and array establishing method

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a mirror image 3D MIMO half-wave antenna array and an array establishing method.

Background

The traditional 2D MIMO half-wave antenna array technology is mature, but the side lobe and the main lobe of a shaped beam generated by an antenna in the propagation direction are generally large, so that the radiation energy is lost, and interference can be generated. The existing 3D MIMO half-wave antenna array has good beam forming and directionality effects, even if the 3D MIMO half-wave antenna array only has two array elements in the transmission direction, the beam forming of the 3D MIMO half-wave antenna array also has three distances and three phase differences and other parameters of adjacent array elements for system adjustment, and still has excellent adjustability in the aspect of function processing such as beam forming, but because three-dimensional array element control is needed, the number of the array elements is more, and the control technology and the hardware architecture are more complex.

In the process of implementing the embodiment of the invention, the inventor finds that the beam forming effect of the existing 2D MIMO half-wave antenna array is not ideal, while the technical difficulty of the existing 3D MIMO half-wave antenna array is higher, the cost is higher, and the volume and the weight are larger.

Disclosure of Invention

The embodiment of the invention provides a mirror image 3D MIMO half-wave antenna array and an array establishing method, which are used for solving the problems that the beam forming effect of the existing 2D MIMO half-wave antenna array is not ideal, and the technical difficulty of the existing 3D MIMO half-wave antenna array is higher, the cost is higher, and the size and the weight are larger.

In a first aspect, an embodiment of the present invention further provides a mirror image 3D MIMO half-wave antenna array, including: the device comprises a 2D MIMO half-wave antenna array and a reflector;

the 2D MIMO half-wave antenna array is arranged on the mirror surface side of the reflector;

and a virtual image of the 2D MIMO half-wave antenna array in the reflector and the 2D MIMO half-wave antenna array form a mirror image 3D MIMO half-wave antenna array.

Optionally, a distance between the 2D MIMO half-wave antenna array and the mirror is less than 0.5 λ, where λ is a wavelength of an electromagnetic wave in the 2D MIMO half-wave antenna array.

Optionally, the distance between the 2D MIMO half-wave antenna array and the mirror is 0.125 λ.

Optionally, the virtual image and the 2D MIMO half-wave antenna array are simulated by using a finite difference time domain method FDTD to form a mirror image 3D MIMO half-wave antenna array.

Optionally, the mirror is a metal mirror.

In a second aspect, an embodiment of the present invention provides a mirror image 3D MIMO half-wave antenna array establishing method, including:

determining the distance between the 2D MIMO half-wave antenna array and the reflector;

setting the 2D MIMO half-wave antenna array and the reflector according to the distance;

and simulating the virtual image and the 2D MIMO half-wave antenna array to establish a mirror image 3D MIMO half-wave antenna array.

Optionally, the determining the distance between the 2D MIMO half-wave antenna array and the mirror specifically includes:

and determining the distance between the 2D MIMO half-wave antenna array and the reflector according to the maximum value of the main lobe and the included angle of the main lobe.

Optionally, the simulating the virtual image and the 2D MIMO half-wave antenna array to establish a mirror image 3D MIMO half-wave antenna array includes:

and simulating the virtual image and the 2D MIMO half-wave antenna array by adopting the FDTD to establish a mirror image 3D MIMO half-wave antenna array.

According to the technical scheme, the mirror image technology is adopted, and the reflector is added on the basis of the 2D MIMO half-wave antenna array, so that the 2D MIMO half-wave antenna array can generate a virtual image behind the mirror surface of the reflector to form the mirror image 3D MIMO half-wave antenna array, the cost, the technology, the volume and the weight of the mirror image 3D MIMO half-wave antenna array are almost the same as those of the 2D MIMO half-wave antenna array, and the beam forming is far better than that of the 2D MIMO half-wave antenna array.

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 description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a mirror image 3D MIMO half-wave antenna array according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a basic element antenna according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a linear antenna with a radiation field at P according to an embodiment of the present invention;

fig. 4 is a schematic mirror image diagram of a mirror front half-wave antenna according to an embodiment of the present invention;

FIG. 5 shows a_x＝0°、α_y＝-60°、α_zThe transmission diagram and the direction diagram of the 2X 1X 2 mirror image 3D MIMO half-wave antenna array are 0 degrees;

fig. 6 shows an embodiment of a 2 × 1 × 2 mirror 3D MIMO half-wave antenna array at α_x＝0°、α_y＝-60°、α_zLobe of 0 DEG and d_yA schematic diagram of the relationship of (1);

fig. 7 shows an embodiment of a 2 × 1 × 2 mirror 3D MIMO half-wave antenna array at α_x＝100°、α_y＝-60°、α_zLobe of 0 DEG and d_yA schematic diagram of the relationship of (1);

fig. 8 shows an embodiment of a 2 × 1 × 2 mirror 3D MIMO half-wave antenna array at α_x＝0°、α_y＝-60°、α_zLobe of 100 DEG and d_yA schematic diagram of the relationship of (1);

fig. 9 is a schematic diagram of a mirror image 3D MIMO half-wave antenna array architecture according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a Yee cell in the FDTD algorithm according to an embodiment of the present invention;

FIG. 11 shows a_x＝0°、α_y＝0°、α_zThe antenna array propagation diagram and the direction diagram of the 2 × 2 × 23D MIMO half-wave antenna are 0 degrees;

FIG. 12 shows a_x＝0°、α_y＝-120°、α_zThe antenna array propagation diagram and the direction diagram of the 2 × 2 × 23D MIMO half-wave antenna are 0 degrees;

fig. 13 is a schematic flowchart of a mirror image 3D MIMO half-wave antenna array establishment method according to an embodiment of the present invention;

FIG. 14 is a logic block diagram of an electronic device in one embodiment of the invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Fig. 1 shows a schematic structural diagram of a mirror-image 3D MIMO half-wave antenna array provided in this embodiment, including: a 2D MIMO half-wave antenna array 101 and a mirror 102;

the 2D MIMO half-wave antenna array 101 is arranged on the mirror surface side of the reflector 102;

wherein a virtual image of the 2D MIMO half-wave antenna array 101 in the reflector 102 forms a mirror image 3D MIMO half-wave antenna array with the 2D MIMO half-wave antenna array 101.

The 2D MIMO half-wave antenna array is a two-dimensional multi-input multi-output half-wave antenna array; the 3D MIMO half-wave antenna array is a three-dimensional multi-input multi-output half-wave antenna array.

Specifically, a half-wave antenna array refers to that an array element is a half-wave antenna, a so-called half-wave antenna refers to a symmetric linear antenna with an antenna length of half a wavelength, and a radiation field of a linear antenna with a limited length at a certain point in space can be regarded as superposition of radiation fields of infinite element antennas at the certain point. By element antenna is meant a length d_zUniformly distributed current Id of I_zAntennas with elementary currents. Because the element current is small, the element antenna is short, and the receiving area is relatively far away, the element antenna can be regarded as a basic radiating element. FIG. 1 shows the case of a cellular antenna in a rectangular coordinate system and a spherical coordinate system, and it can be easily found that the cellular antenna is far away

The electric field of the spot can be simplified to E_r、E_θ、

Three components.

According to the antenna theory, the analysis basis of the half-wave antenna array is a half-wave antenna, the analysis basis of the half-wave antenna is a linear antenna, the analysis basis of the linear antenna is an element antenna, and the element antenna is the analysis basis of all antenna systems.

According to electromagnetic field theory, in the coordinate system of fig. 2, the vector bit (vector potential) generated at P by the element current I along the Z-axis in the element antenna can be expressed as:

the vector A can also be decomposed into

The transformation matrix of the spherical coordinates and the rectangular coordinates is as follows:

from fig. 2A, it can be seen that the rectangular coordinate component of the vector bit of the element antenna at P has a_x＝A_yWhen the vector bit of the meta-antenna at P is 0, the spherical coordinate component of the vector bit of the meta-antenna at P can be obtained as a according to equation (2)_r＝A_zcosθ，A_θ＝A_zsinθ，

And because the relationship between the electric field E and the magnetic field H and the vector bit A is as follows:

the spherical coordinate component of the electromagnetic field of the element antenna at P can be obtained according to equation (3) as:

in the formula

Dielectric constant in vacuum₀＝8.854×10^-12F/m, magnetic permeability μ₀＝4π×10^-7H/m, wave number k 2 pi/λ, dielectric wave resistance η √ (μ /), and vacuum wave resistance η √₀＝120πΩ。

Since equation (4) is more complex, only the far field region is used to simplify the approximation analysis. The far field region means that the position of P satisfies kr>>1, only 1/r item needs to be reserved in the electromagnetic field component, and other items can be ignored, so that only one item in the far field region is reserved

And E_θTwo components, E_rThe components are ignored, i.e.:

according to the formula (5), the electromagnetic field of the element antenna in the far-field region is only E_θAnd

two components, the symmetric linear antenna is regarded as the infinite element antenna to be added, as shown in FIG. 3, the far field is obtained

Electric field E of the spot_θ. If the P point is located in the far field region, and the wavelength of the antenna signal excitation current is lambda and the amplitude is I_mAnd points to the positive direction of the Z axis, according to the antenna theory, the current on the symmetrical linear antenna can be approximately distributed in a triangular shape, namely when Z is more than or equal to 0, the excitation current of the signal is I (Z) I_msink(l-z)、z<The excitation current of the signal at 0 is I (z) ═ I_msink (l + z), according to equation (9), current element (or element antenna) Id on the symmetric linear antenna_zThe radiated electric field at the far field region P point can be expressed as:

wherein the element antenna Id_zThe distance from the P point of the far field region is as follows:

due to R²＝x²+y²+z²And z is Rcos θ, then the distance r can be expressed as:

the R value is expanded by a binomial expression, the first two terms are approximate, and then R is approximately equal to R-z' cos θ. For distance, R ≈ R for the far field, and R ≈ R-z' cos θ for the phase, which is substituted into equation (6) to obtain:

obviously, the radiation electric field of the element antenna in the far-field region is only related to the tilt angle θ and the distance R of the antenna. Integrating the antenna length 2L, the electric field of the symmetric linear antenna at the P point of the far field region can be expressed as:

if the modulus value is taken for E (theta), then there are

Where f (θ) is a directional diagram function of the symmetrical linear antenna in the far-field region, and can be expressed as:

setting the maximum value of the directional diagram function of the symmetrical linear antenna as f_mThen, the normalized directional diagram function of the symmetric linear antenna is: f theta) F (theta)/F_mOr, alternatively:

when the length 2L of the symmetrical linear antenna is lambda/2, the symmetrical linear antenna is called a half-wave antenna or a half-wave oscillator, and at the moment, kL is pi/2, f is taken_m1, the half-wave antenna pattern function is:

if the half-wave antenna is placed in front of the metal mirror surface, a virtual image of the half-wave antenna is generated behind the mirror surface, as shown in fig. 4. It can be seen that in the mirror surfaceThe electromagnetic field at the point P in front is generated by superposition of a half-wave antenna and a half-wave antenna virtual image. If the current of the vibration source of the half-wave antenna is I, the distance d from the mirror surface in the Y-axis direction_yInitial phase of vibration source alpha_yAccording to the theory of electromagnetic field, not only the distance between the vibration source and the virtual image of the vibration source is 2d_yThe phase difference between the vibration source and the virtual image of the vibration source is also 2 alpha_y. Therefore, when XYZ coordinate system is set on the mirror surface as shown in FIG. 3, psi is taken_y＝α_y+kd_ysin θ sin φ, the electric field of the vibration source at P can be expressed as E ═ Ie^{+αx+jkdysinθsinφ}＝Ie^+jψyIf the reflecting surface is lossless, the electric field of the virtual image of the vibration source at P can be expressed as E ═ I' E^{-αx-jkdysinθsinφ}＝Ie^{-αx-jkdysinθsinφ}＝Ie^-jψy。

Similarly, if the two-dimensional half-wave antenna array is arranged in front of the metal mirror surface d_yD, which may likewise be behind the mirror surface_yA two-dimensional half-wave antenna array virtual image is obtained (as shown in fig. 1), and a physically two-dimensional and logically three-dimensional mirror image three-dimensional half-wave antenna array is formed. Although the mirror image three-dimensional half-wave antenna array has only two array elements on the Y axis, the distance d between the vibration source and the mirror surface is adjusted_yAnd the initial phase alpha of the vibration source on the Y axis_yThe same beam forming effect in the Y-axis direction as the three-dimensional half-wave antenna array can be obtained. In contrast, d of mirrored three-dimensional half-wave antenna array_yAnd alpha_yAnd the parameter value is half of the three-dimensional half-wave antenna array.

Analysis in front of the distance mirror d_yTwo-dimensional physical half-wave antenna array on XZ plane:

let the phase difference of the exciting currents of the adjacent X-axis antennas be alpha_xThe initial phase of the excitation current of the Y-axis antenna is alpha_yThe phase difference of the excitation current of the adjacent Z-axis antenna is alpha_zDue to the mirror reflection surface d of the two-dimensional half-wave antenna array pitch_ySo that the excitation current of the 1 st row and 1 st column elements on the X-axis is I₁₁e^+jψyThe excitation current of the 1 st row and the 2 nd column array elements is I₁₂＝I₁₁e^jαx+jψy…, line 1, n_xArray element excitation current is I_1nx＝I₁e^{j(nx-1)αx+jψy}The excitation current of the 2 nd row, 1 st column array element is I₂₁＝I₁₁e^jαz+jψyThe excitation current of the 2 nd row and 2 nd column elements is I₂₂＝I₂₁e^jαx＝I₁₁e^{j(αx+αz)+jψy}…, line 2, n_xArray element excitation current is I_2nx＝I₂₁e^j(nx-1)αx＝I₁₁e^{j[(nx-1)αx+αz]+jψy}…, n_zThe row 1, column array elements have excitation current of I_nz1＝I₁₁e^{j(nz-1)αz+jψy}N th_zThe row 2 nd array element has an excitation current of I_nz2＝I_nz1e^jαx＝I₁₁e^{j[(nz-1)αz+αx]+jψy}…, n_zLine n_xArray element excitation current is I_nznx＝I_nz1e^j(nx-1)αx＝I₁₁e^{j[(nx-1)αx+(nz-1)αz]+jψy}Then, the electric field generated by each array element independently can be expressed as:

since r > Nd, taking a first approximation of its Taylor expansion, one can define the complex median:

similarly, the median of denominator and real number can be defined

r₁₂≈…≈r_1nx≈…≈r₂₁≈…≈r_2nx≈…≈r_nznx≈r₁₁ (14)

Substituting the expressions (13) and (14) into the expression (12) to obtain:

defining:

ψ_z＝α_z+kd_zcosθ (17)

and (5) adding the formula (15), and substituting the formulas (16) and (17) to obtain:

due to I₂₁＝I₁₁e^jαz、…、I_nz1＝I₁₁e^j(nz-1)αzIn the denominator r₂₁≈…≈r_nz1≈r₁₁In complex number r₂₁≈r₁₁-d_zcosθ、…、r_nz1≈r₁₁-(nz-1)d_zcos θ, then:

superposing the electric fields of all array elements in the half-wave antenna array at the position P:

E＝E₁+E₂+…

+E_nz＝E₁₁[(1-e^jNxψx)e^jψy/(1-e^jψx)]+E₂₁[(1-e^jNxψx)e^jψy/(1-e^jψx)]+…

+E_nz1[(1-e^jNxψx)e^jψy/(1-e^jψx)]

＝E₀I₁₁/r₁₁e^-jkr11[cos(π/2cosθ)/sinθ][(1-e^jNxψx)/(1-e^jψx)]e^jψy[(1-e^jNzψz)/(1-

e^jψz)] (20)

re-analysis of d from the metal mirror surface_yTwo-dimensional on the XZ plane of (A)A half-wave antenna array virtual image.

According to the mirror image principle, by means of the formula (20), the total electric field of all virtual array element images of the two-dimensional half-wave antenna array virtual image at P can be expressed as:

E`＝E₀I₁₁/r₁₁e^-jkr11[cos(π/2cosθ)/sinθ][(1-e^jNxψx)/(1-e^jψx)]e^-jψy[(1-e^jNzψz)/

(1-e^jψz)] (21)

finally, the common total field of the two-dimensional half-wave antenna array and the two-dimensional half-wave antenna array virtual image at P can be represented as:

Es＝E+E`＝E₀I₁₁/r₁₁e^-jkr11[cos(π/2cosθ)/sinθ][(1-e^jNxψx)/(1-e^jψx)]

[(1-e^jNzψz)/(1-e^jψz)](e^jψy+e^-jψy) (22)

according to the formula e^jθ＝cosθ+jsinθ，e^-jθThe formula (26) can be expressed as:

Es＝E₀I₁₁/r₁₁e^-jkr11[cos(π/2cosθ)/sinθ][(1-e^jNxψx)/(1-e^jψx)][(1-e^jNzψz)/(1-e

^jψz)][2cosψ_y]

taking an absolute value to obtain:

|E|＝|E₀I₁₁/r₁₁e^-jkr11|[cos(π/2cosθ)/sinθ][sin(N_xψ_x/2)/sin(ψ_x/2)][sin(N_zψ_z

/2)/sin(ψ_z/2)]2cosψ_y (23)

therefore, the pattern function of a mirrored three-dimensional half-wave antenna array can be expressed as:

the normalized directional diagram function of the mirror image three-dimensional half-wave antenna array is as follows:

apparently, [ cos (π/2cos θ)/sin θ]Is the directional diagram function of the half-wave antenna, [ sin (N)_xψ_x/2)/sin(ψ_x/2)]Is the array factor of the parallel vibrator along the X axis, [ sin (N)_zψ_z/2)/sin(ψ_z/2)]Is the array factor of the coaxial vibrator along the Z axis, [2cos psi [ ]_y]Is the array factor of the array element and the array element virtual image on the Y axis. It should be noted that the distance between two adjacent array elements in the Y-axis array factor is 2d_yThat is to say, the thickness of the two-dimensional half-wave antenna array is converted into the thickness of the mirror three-dimensional half-wave antenna array in a mirror reflection mode, and is only half of the thickness of the three-dimensional half-wave antenna array.

In addition, the directional diagram function of the three-dimensional half-wave antenna array is as follows:

as with equation (25), the normalized directional pattern function of the three-dimensional half-wave antenna array is:

in fact, a mirror image three-dimensional half-wave antenna array directional diagram function can be derived by using the three-dimensional half-wave antenna array directional diagram function. Get N_y＝2，d_y＝2d_y`，α_y＝2α_yV. then psi_y＝α_y+kd_ysinθsinφ＝2α_y`+k2d_y`sinθsinφ＝2ψ_y"substituted into the second term Y-axis array factor [ sin (N) in equation (26)_yψ_y/2)/sin(ψ_y/2)]The method can be obtained by the following steps:

[sin(N_yψ_y/2)/sin(ψ_y/2)]＝[sin(2ψ_y`)/sin(ψ_y`)]＝2cos(ψ_y`) (28)

then, formula (24) can be obtained by substituting formula (28) into formula (26). Therefore, from the analytic analysis, the mirror image three-dimensional half-wave antenna array is actually a three-dimensional half-wave antenna array with only two array elements on the Y axis, and the parameter d of the mirror image three-dimensional half-wave antenna array_yAnd α Y, only half of the parameters corresponding to the three-dimensional half-wave antenna array with two array elements on the Y axis.

Let f be 6GHz, λ be c/f, and c be 3 × 10⁸Is the speed of light in vacuum. The number of the array elements of the 3D MIMO half-wave antenna array element on the X, Y, Z axis is Nx-2, Ny-2 and Nz-2, the distance between every two adjacent array elements is dx-lambda/2, D_y＝λ/4、d_z0.6 lambda, phase difference of each adjacent array element is alpha_x＝0°、α_y＝0°～-120°、α _z0 deg.. According to the formula (27), the normalized directional diagram of the 3D MIMO half-wave antenna array can be solved analytically, as shown in fig. 5D and 11D.

If space step length D is taken_x＝D_y＝D_zλ/24, time step Dt is Dx/(2c), and array element spacing d_x12 cells, d_y6-membered cell, d_z14-unit cell. If PML region 8 cells, array element active region and total field interval 42 cells are arranged, the number of cells of FDTD in three-dimensional space is s_x＝112、s_y＝106、s_z114. The number of time iterations 400 is taken into account of microcomputer memory space and CPU performance. According to the formulas (29) and (30), the electromagnetic wave radiation pattern and the directional diagram of the 3D MIMO half-wave antenna array can be obtained by using FDTD and PML simulation, and are shown in A-C diagrams in figures 5 and 11.

As can be seen from fig. 5 and 11, in the 3D MIMO half-wave antenna array, the phase difference α between the Y-axis elements_yDetermining the distribution of the beam on the Y axis when alpha is_yWhen the angle is equal to 0 degrees, the main lobe and the auxiliary lobe are the same and are distributed at two ends of the Y axis; when alpha is_yThe minor lobe is extremely small at-120 deg. and the major lobe is distributed in the Y-axis forward direction, see fig. 5 and 11. The 3D MIMO half-wave antenna array has excellent directivity and can pass through D_x、d_y、d_z、α_x、α_y、α_zConvenient six-parameter adjustment beamformingAnd (4) shaping.

Setting the number of the array elements of the 2D MIMO half-wave antenna array on the X, Z axis as N_x＝2、N _z2, the distance between adjacent array elements is dx lambda/2, d_z0.6 lambda, the phase difference between adjacent array elements is alpha_x＝0°、α _z0 deg.. Setting the distance between the 2D MIMO half-wave antenna array and the rear metal silver mirror surface as D_yλ/8, the initial phase of the array element on the Y axis is α_y-60 °. And (5) resolving to obtain a normalized directional diagram of the mirror image 3D MIMO half-wave antenna array according to the formula (25), and the normalized directional diagram is shown in figure 12D.

According to the same space step length, the array element spacing d_x12 cells, d_zDistance D between 2D MIMO half-wave antenna array and mirror surface as 14 cells_y3-unit cell. Taking metallic silver as a reflector and the electrical conductivity sigma_Ag＝6.25×10⁷Siemens per meter, or copper sigma_Cu＝5.88×10⁷And aluminium sigma_Al＝3.72×10⁷To reduce the cost. According to the formulas (29) and (30), the electromagnetic wave radiation pattern and the directional diagram of the mirror image 3D MIMO half-wave antenna array can be obtained by using FDTD and PML simulation, and the electromagnetic wave radiation pattern and the directional diagram are shown in figures 5A-5C.

The structure of the mirror image 3D MIMO half-wave antenna array mainly comprises the following components from top to bottom: a protective shell, an array unit, an array element supporting surface, a bracket between the array element surface and the reflector surface, a metal coated reflector surface, a substrate, a phased power amplifier and other element integrated surfaces, a bottom plate used as the back surface of the shell and other parts, wherein, the array element supporting surface, the bracket and other parts are reinforced engineering plastic parts, the interface of the bracket and the supporting surface is connected by a nonmetal screw-free interface card, the whole array element supporting surface and the bracket are reinforced plastic parts except the array elements and the information connecting line, all the array elements on the array element supporting surface are connected with the integrated components behind the mirror reflection surface by adopting an integrated parallel data line, put through antenna housing edge cloth, except there being a small amount of non-metallic support between array element holding surface and the mirror image reflection mirror face, do not have any other metal parts that can produce the interference to the electromagnetic wave to guarantee the mirror image reflection effect of speculum to array element.

According to the embodiment of the invention, a mirror is added on the basis of the 2D MIMO half-wave antenna array by adopting a mirror image technology, so that the 2D MIMO half-wave antenna array can generate a virtual image behind the mirror surface of the mirror to form a mirror image 3D MIMO half-wave antenna array, the cost, the technology, the volume and the weight are almost the same as those of the 2D MIMO half-wave antenna array, but the beam forming is far better than that of the 2D MIMO half-wave antenna array.

Further, on the basis of the above embodiment, the distance between the 2D MIMO half-wave antenna array and the mirror is less than 0.5 λ, where λ is the wavelength of the electromagnetic wave in the 2D MIMO half-wave antenna array.

Specifically, the main technical index of the mirror image 3D MIMO half-wave antenna array is the distance D between the 2D MIMO half-wave antenna array and the mirror_y. The performance of the mirror image 3D MIMO half-wave antenna array is mainly the lobe effect, namely the larger the main lobe strength is, the better the main lobe included angle is, the smaller the side lobe is, the better the performance is. The beam effect of the half-wave antenna array is related to the azimuth angle and the inclination angle of the beam when the azimuth angle is 90 degrees or alpha_xWhen the angle is 0 degrees, the side lobe of the horizontal lobe is almost 0; when the inclination angle is 90 DEG or alpha_zAt 0 °, the side lobe of the vertical lobe is almost 0, as shown in fig. 6C. When α is_xNot equal to 0 DEG or alpha_zWhen the angle is not equal to 0 degrees, the horizontal lobe or the vertical lobe generates side lobes, the larger the absolute value of the angle is, the larger the strength of the side lobes is, the larger the number of the side lobes is, and even the strength of the side lobes exceeds that of the main lobe. But by moderate adjustment of the spacing d_yAnd the azimuth angle and the inclination angle of the array beam are within a proper adjustment range, so that a better lobe effect can be obtained.

Taking array basic parameter f as 6GHz, Nx as 2, Nz as 2, alpha_x＝0°～100°、α_y＝-60°、α_z＝0°～100°、d_x＝λ/2、d_z0.6 lambda, when the distance D between the 2D MIMO half-wave antenna array and the reflector_yWhen the wave beam is equal to 0-0.5 lambda, obtaining the normalized maximum value of the horizontal lobe and the vertical lobe of the main lobe of the mirror three-dimensional MIMO half-wave antenna array, the beam included angle and the beam included angle d according to the formula (25)_yAnd d corresponding to the maximum beam intensity_yNormalized directional pattern of horizontal and vertical lobes of timeSee FIGS. 6-8 for an analysis of the array versus mirror spacing. So that only d is analyzed_yThe range of 0 to 0.5 λ is considered to reduce the thickness of the array antenna, and is just the main range of the array performance variation.

FIG. 6 shows a 2 × 1 × 2 mirror 3D MIMO half-wave antenna array at α_x＝0°、α_y＝-60°、α_zMaximum value of lobe and included angle with d when equal to 0 DEG_yA varying relation curve, and d_yPattern curve at 0.167 λ. It can be seen that the maximum value of the beam follows d_yIn the varying curve, the horizontal lobe completely coincides with the vertical lobe curve, because the horizontal lobe and the vertical lobe are curves taken by the same beam at different cross sections. Normalized maximum value corresponds to d_yThe optimum value range is 0-0.3 lambda; included angle of beam with d_yIn the changed curve, the difference between the horizontal lobe and the vertical lobe is larger because the horizontal lobe array elements are distributed in parallel by the half-wave antenna, and the vertical lobe array elements are distributed axially by the half-wave antenna, so that the included angle of the vertical lobe is smaller than that of the horizontal lobe, and the change of the included angle of the vertical lobe is slower than that of the horizontal lobe. The optimal value range of the two is still 0-0.3 lambda.

FIG. 7 shows a 2 × 1 × 2 mirror 3D MIMO half-wave antenna array at α_x＝100°、α_y＝-60°、α_zMaximum value of lobe and included angle with d when equal to 0 DEG_yA varying relation curve, and d_yPattern curve at 0.201 λ. It can be seen that the maximum of the horizontal lobe versus the vertical lobe is d_yThe curves of variation are completely coincident, and the normalized maximum value corresponds to d_yThe optimum value range is 0.1 lambda-0.3 lambda; angle between horizontal lobe and vertical lobe with d_yThe curves of the changes differ greatly. Because only the phase difference of adjacent array elements on the X axis is taken as alpha _x100 degrees, so only the horizontal lobe changes greatly, the azimuth angle is 124 degrees, two large side lobes are generated on two sides of the main lobe, the energy distribution of the main lobe is influenced, and the included angle of the horizontal lobe and the d are changed_yThe curved shape of (2). Angle of vertical lobed_yBecomes more varied, the beam angle and the tilt angle are hardly varied, indicating a_xThe change in (c) has little effect on the vertical lobe.

FIG. 8 shows a 2 × 1 × 2 mirror 3D MIMO half-wave antenna array at α_x＝0°、α_y＝-60°、α_zMaximum of lobe and angle with d at 100 deg_yA varying relation curve, and d_yPattern curve at 0.176 λ. It can be seen that the maximum of the horizontal lobe versus the vertical lobe is d_yThe curves of the variation are overlapped, and the normalized maximum value corresponds to d_yThe optimum value range is 0.1 lambda-0.3 lambda; angle between horizontal lobe and vertical lobe with d_yThe curves of the changes differ greatly. The method is mainly characterized in that only the phase difference value of adjacent array elements on the Z axis is alpha_z100 deg. so that the vertical lobe has an inclination of 109 deg. and a side lobe is generated, affecting the energy distribution of the vertical main lobe, of course by changing the angle of the vertical lobe and d_yThe curved shape of (2). While the azimuth angle of the horizontal lobe is still 90 DEG, the included angle of the horizontal lobe and d_yThe curve shape of (a) is also basically unchanged, and similarly, a is illustrated_zThe change in (c) has little effect on the horizontal lobe.

According to the comparison of all the curves in fig. 6-8, the optimal spacing D of the mirror image 3D MIMO half-wave antenna array is considered from the two aspects of the maximum value of the main lobe and the included angle of the main lobe_yD is usually taken to be 0.1 λ to 0.2 λ_yThe distance between the mirror image 3D MIMO half-wave antenna array and the metal mirror surface is D, because 0.125 λ is the position where the 2D MIMO half-wave antenna array is λ/8 away from the metal mirror surface, which is exactly half of the Y-axis adjacent array element distance λ/4 in the typical 3D MIMO half-wave antenna array, so we design the mirror image 3D MIMO half-wave antenna array_yλ/8. As can be seen from the directional diagram, the difference between the horizontally adjacent array elements is alpha_xWhen the azimuth angle of the wave beam is changed, the influence on the inclination angle of the wave beam is small, otherwise, the difference between the vertical adjacent array elements is alpha_zWhen the beam inclination angle is changed, the influence on the beam azimuth angle is not large, and the distance D between the X-axis adjacent array elements on the 2D MIMO half-wave antenna array is still designed in consideration of the array size_xLambda/2, and the distance between adjacent array elements in the Z axis is d_z0.6 λ, see fig. 9.

Further, on the basis of the above embodiment, the virtual image and the 2D MIMO half-wave antenna array are simulated by using a finite difference time domain method FDTD to form a mirror image 3D MIMO half-wave antenna array.

Specifically, the FDTD (Finite Difference Time Domain) is an iterative numerical value algorithm which performs Finite Difference dispersion on Maxwell rotation equation based on Time and space, has two-order precision, and replaces differential form with central Finite Difference format approximation. FDTD differentiates Maxwell differential equation in space-time two domains simultaneously, alternately calculates electric field and magnetic field in space domain by frog leaping mode, and simulates field intensity change in time domain by updating mode. The FDTD analysis electromagnetic field needs to consider the geometric parameters and the material parameters of a research object, so that the calculation precision, the complexity and the stability are high, and the simulation precision is high. Parameters of FDTD simulation space electromagnetic properties are given according to a space grid, and complex electromagnetic structures can be simulated only by giving medium parameters of corresponding space points. FDTD solves finite difference equation under proper boundary and initial condition, describes complex physical process with clear image, can directly reflect time domain characteristic of electromagnetic wave, can express abundant time domain information of electromagnetic field, and is an important method for modern electromagnetic field research.

The FDTD mesh division adopts a structural mode that space and time are different by half step length provided by Yee, obtains the electric and magnetic field values at the current moment by using the magnetic and electric field values at the previous moment through a frog leap step, and calculates the process in the whole space at each moment, thereby obtaining the time domain solution of the electric and magnetic fields which change along with time in the whole space. If Fourier transform is used for the time domain solution, a corresponding frequency domain solution can be obtained. Although the action area of the electromagnetic field is infinite, the calculation space of the FDTD is limited, namely the number of Yee grids consisting of Yee cells (shown in figure 10) is limited, an electromagnetic field absorption area, such as an approximate absorption boundary MUR and a complete matching absorption boundary PML, must be arranged at the boundary of the total field area of the FDTD, wherein the complete matching of the PML absorption boundary ensures that the almost complete absorption of the electromagnetic field propagating to the total field boundary is eliminated, and the electromagnetic wave propagation effect in the simulation infinite space is very real. FDTD and PML boundaries are adopted to analyze the electromagnetic field propagation between the simultaneous frequency transceiving antennas which are adaptive to 5G requirements, and ideal effects can be completely obtained.

The Maxwell rotation equation consists of ampere loop law and Faraday's electromagnetic induction law, and the vector formula is

Wherein D-E, B- μ H, J- σ E, J_m＝σ_mH. If the vector equation is developed into a scalar equation of a rectangular coordinate system, the first-order partial derivatives of the time domain and the space domain are subjected to center difference approximate dispersion, and the FDTD equation can be obtained after arrangement, wherein the electric field E_xThe equation is:

due to E_y、E_zAnd E_xHaving perfect duality and xyz subscript cyclicity, can be derived separately from equation (29).

Similarly, the magnetic field H of the FDTD equation_xThe equation is:

same cause H_y、H_zAnd H_xHas complete duality and xyz subscript cyclicity, and can be derived according to equation (30) respectively.

(29) And (30) the coefficients in the equations are: c_a(m)＝{1-[σ(m)Δt]/[2(m)]}/{1+[σ(m)Δt]/[2(m)]}、C_b(m)＝{Δt/(m)}/{1+[σ(m)Δt]/[2(m)]}、C_p(m)＝{1-[σ_m(m)Δt]/[2μ(m)]}/{1+[σ_m(m)Δt]/[2μ(m)]}、C_q(m)＝{Δt/μ(m)}/{1+[σ_m(m)Δt]/[2μ(m)]And m takes the value of the Yee cell subscript of each calculation area. Obviously, the expressions (29) and (30) are iterative expressions whose time instants are calculated from previous time instants in the time domain, each time instant is fully overlapped in the spatial domain, and the characteristics of the Yee cells are represented by (m), μ (m), σ (m), and σ (m) of the positions of the Yee cells_m(m) determining. When the total field is vacuum, the scatterer is a metal surfaceIn this case, the cell parameter σ (m) of the Yee cell corresponding to the scatterer is different from that of the other scatterer₀、μ(m)＝μ₀、σ(m)＝0、σ_mWhen (m) ═ 0, the FDTD equation is very simple. In addition, the spatial steps Δ x, Δ y, Δ z and the time step Δ t should satisfy Courant stability conditions, i.e., Δ x, Δ y, Δ z ≦ λ/12, and Δ t ≦ min (Δ x, Δ y, Δ z)/c, to ensure convergence of the FDTD equation iteration, and generally, Δ x ═ Δ y ≦ Δ z ≦ λ/20, Δ t ≦ Δ x/(2c), λ is the electromagnetic field wavelength, and c is the vacuum light velocity.

Because the FDTD modeling can be highly matched with a real scene, under the premise of the permission of computing resources, when the values of the space step length delta x, the delta y, the delta z and the time step length delta t are small enough, and the time iteration number is large enough, the FDTD simulates the electromagnetic field propagation of the three-dimensional half-wave antenna array, is very close to the real scene, not only can qualitatively visualize the electromagnetic field propagation condition, but also can quantitatively obtain data close to the reality. However, due to the limited computing resources and the limited number of FDTD cells, the dynamic electromagnetic field transmission analysis area can only be a small electric environment, or FDTD is mainly used for analyzing the dynamic electromagnetic field transmission distribution of the near-field area of the antenna as the analytic expression (26) can only analyze the directional pattern of the far-field area of the antenna, so that the analytic expression and the FDTD can complement each other in the far-field area and the near-field area of the antenna.

The difference between the FDTD propagation and directivity diagrams from the analytic directivity diagrams of fig. 5 and 12, where the FDTD directivity diagram has a larger lobe angle than the analytic lobe angle, is small because the analytic adaptation to the far-field region and the FDTD adaptation to the near-field region. By comparing fig. 5 and fig. 12, it can be seen that there is a side lobe in the negative Y-axis direction in the FDTD propagation diagram of fig. 12, but there is no side lobe in the negative Y-axis direction in the FDTD propagation diagram of fig. 5, which indicates that the mirror-image 3D MIMO half-wave antenna array not only can obtain the same effect as the 3D MIMO half-wave antenna array, but also may be excellent in some aspects.

Further, on the basis of the above embodiment, the reflecting mirror is a metal mirror.

The mirror surface of the metal mirror is an important part for generating mirror image array elements, the higher the reflectivity is, the higher the similarity of the mirror image array elements is, and the better the mirror image three-dimensional effect is. One of the advantages of the mirror image 3D MIMO antenna array is that it is thin, for the convenience of installation of the two-dimensional array and the metal mirror, the mirror surface needs to satisfy the characteristics of light, thin, flat and high reflectivity, and we design the mirror surface to be a silver-plated organic material, because the high-frequency skin effect is strong, the electromagnetic wave incident into the metal is very shallow, and the high-frequency electromagnetic wave can complete reflection in the silver-plated layer, so that the reflection performance can be improved, the cost is saved, the weight is reduced, and the selection and installation of the reflection material can be facilitated. Because the distance between the 2D MIMO half-wave antenna array and the metal mirror surface is very small, control elements such as the weight, the phase and the like of the array elements can be placed behind the metal mirror surface or directly integrated on the other surface of the metal mirror surface, and the array elements are controlled and signals of the vibration elements are received and transmitted through edge data connection lines.

In array element control system, because of only two array elements of half-wave antenna and half-wave antenna virtual image are gone up to Y axle direction, so only need increase the initial phase ware of Y axle direction on the array element, although initial phase ware can adjust initial value, but function singleness, simple structure. In addition, the phase difference between the adjacent array elements of the X axis and the Z axis in the 2D MIMO half-wave antenna array is respectively given by the phase shift controllers. In order to better control the beam forming, a weight controller is also needed to control the amplitude of the transmitted signal on each array element. Because these controllers are all the mature parts of technology, the integration level and standardization are very high, can integrate on the other side of the reflector material completely, make it become an organic whole with the reflector, or make controller and reflector form the module supporting 4 and more than 4 array elements, the whole array is not only inserted to form by a plurality of modules, can save space and weight, but also easy to assemble and maintain, can also reduce the technical difficulty and cost.

The embodiment takes the 2D MIMO half-wave antenna array as a technical basis to realize the effect of the 3D MIMO half-wave antenna array, and has the advantages that the two-dimensional half-wave antenna array realizes the functions of beam forming and the like of the three-dimensional half-wave antenna array, and the beam forming effect is superior to that of the microstrip patch antenna array. Due to the mature technology of the two-dimensional half-wave antenna array, the design scheme has the advantages of simple structure, easy realization and certain feasibility and practicability.

Fig. 13 shows a schematic flow chart of a mirror image 3D MIMO half-wave antenna array establishment method provided in this embodiment, including:

s1301, determining the distance between the 2D MIMO half-wave antenna array and the reflector;

s1302, setting the 2D MIMO half-wave antenna array and the reflector according to the distance;

s1303, simulating the virtual image and the 2D MIMO half-wave antenna array, and establishing a mirror image 3D MIMO half-wave antenna array.

Further, on the basis of the above method embodiment, S1301 specifically includes:

Further, based on the foregoing method embodiment, S1303 specifically includes:

The mirror image 3D MIMO half-wave antenna array establishing method described in this embodiment may be used to implement the apparatus embodiments described above, and the principle and technical effect are similar, which are not described herein again.

Referring to fig. 14, the electronic device includes: a processor (processor)1401, a memory (memory)1402, and a bus 1403;

wherein,

the processor 1401 and the memory 1402 communicate with each other via the bus 1403;

the processor 1401 is configured to invoke the program instructions in the memory 1402 to perform the methods provided by the above-mentioned method embodiments, for example, including:

The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising:

The present embodiments provide a non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the methods provided by the above method embodiments, for example, including:

Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

It should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A mirrored 3D MIMO half-wave antenna array, comprising: the device comprises a 2D multiple-input multiple-output MIMO half-wave antenna array and a reflector;

the virtual image of the 2D MIMO half-wave antenna array in the reflector and the 2D MIMO half-wave antenna array form a mirror image 3D MIMO half-wave antenna array;

simulating the virtual image and the 2D MIMO half-wave antenna array, and establishing a mirror image 3D MIMO half-wave antenna array;

the determining the distance between the 2D MIMO half-wave antenna array and the mirror specifically includes:

2. The mirrored 3D MIMO half-wave antenna array of claim 1, wherein the distance between the 2D MIMO half-wave antenna array and the mirror is less than 0.5 λ, where λ is the wavelength of the electromagnetic waves in the 2D MIMO half-wave antenna array.

3. A mirrored 3D MIMO half-wave antenna array according to claim 2, wherein the distance between the 2D MIMO half-wave antenna array and the mirror is 0.125 λ.

4. The mirrored 3D MIMO half-wave antenna array of claim 1, wherein the virtual image and the 2D MIMO half-wave antenna array are simulated by a time domain finite difference method FDTD to form a mirrored 3D MIMO half-wave antenna array.

5. The mirrored 3D MIMO half-wave antenna array of claim 1, wherein the mirrors are metal mirrors.

6. The mirrored 3D MIMO half-wave antenna array of claim 5, wherein the simulating the virtual image and the 2D MIMO half-wave antenna array to establish a mirrored 3D MIMO half-wave antenna array specifically comprises:

and simulating the virtual image and the 2D MIMO half-wave antenna array by adopting FDTD to establish a mirror image 3D MIMO half-wave antenna array.