CN104376224A - Phased array antenna diffraction field calculation method - Google Patents

Abstract

The invention discloses a phased array antenna diffraction field calculation method. The method includes the following steps that radiation fields of phased array elements in an array are calculated; diffraction fields of all the array elements are worked out through an element-by-element method; phased array antenna diffraction fields are solved through vector superposition; the correction coefficients of the antenna radiation fields are solved; the corrected phased array antenna diffraction fields are calculated. The phased array antenna diffraction field calculation method has the advantages that the difficulty in solving the phased array antenna diffraction fields is lowered, and the phased array antenna near-field diffraction difficult to be solved is converted into array element antenna far-field diffraction easy to be solved, so that the solving difficulty is greatly lowered through the existing diffraction theories. The phased array antenna diffraction field calculation method is high in calculation accuracy, and the accuracy of the calculation result is guaranteed through the theoretical strictness. The method is high in calculation efficiency and suitable for developing computer parallel programs and even the phased array antenna with tens of thousands of array elements can obtain the result quickly. The method is good in adaptation and not dependent on the array element type of the phased array antennas.

Description

A kind of phased array antenna diffraction field computing method

Technical field

The invention belongs to antenna and technical field of electromagnetic compatibility, particularly relate to a kind of phased array antenna diffraction field computing method.

Background technology

Phased array antenna has the advantage in inertialess scanning and Fast transforms direction, and radar performance is greatly improved.Due to the progress of electronic technology and the sharply decline of electron device expense, phased array antenna use occasion gets more and more, and increasing civilian platform is equipped with phased-array radar, for weather forecast, navigation, detection etc.Phased Array Radar Antenna generally comprises several thousand little array-element antenna, and general power is larger.On the platform that phased array antenna is installed, usually other electronic equipments are also housed, are also provided with occupied zone.These positions may have object to block, and are the non-direct projection region of antenna, belong to the diffraction region of radiation field of aerial.Because general power is comparatively large, also larger field intensity can be produced in diffraction region.For carrying out electromagnetic interference (EMI) and electromagnetic security analysis, electromagnetic field intensity prediction need be carried out to these regions.But prior art is difficult to the diffraction field accurately, promptly solving phased array antenna.

Summary of the invention

The present invention is directed to the problem that prior art is difficult to accurately, promptly solves phased array antenna diffraction field, a kind of phased array antenna diffraction field computing method are provided, what reduce phased array antenna diffraction field solves difficulty, and precision is high, counting yield is high, and adaptability is good, the array element type that do not rely on phased array antenna.

The technical solution adopted for the present invention to solve the technical problems is: a kind of phased array antenna diffraction field computing method, and the method comprises the following steps, 1) calculate the radiation field of phased array elements in battle array; 2) diffraction field of each array element is solved by first method; 3) vector superposedly phased array antenna diffraction field is solved; 4) radiation field of aerial correction coefficient is solved; 5) the phased array antenna diffraction field after correcting is calculated.

By technique scheme, described step 1) specifically comprise, centered by phased array center position, selection length of side is the square of 2 λ, as phased array antenna subset, λ is the electromagnetic wave wavelength in a vacuum of phased array antenna radiation, array element centered by the array element of phased array center position, center array element applies the excitation of specific power, other array elements connect matched load, active cell method is adopted to calculate the radiation field of this phased array antenna subset, as the radiation field of center array element, and as the radiation field of each array element in this phased array antenna.

By technique scheme, when described center array element is r to aiming spot vector, E is the electric field intensity of r Place object point, and center array element at the radiated electric field of r Place object point is,

$r\·E=r{E}_x\hat{x}+r{E}_y\hat{y}+r{E}_z\hat{z}---\left(1\right)$

Wherein, r=|r|, for the direction vector of r, E _x, E _y, E _zfor the three-component of E, be plural number; When impact point spatial position change, as position, then the electric field of r ' position is

E _r′＝r·E/r′·e ^-jkr′·e ^jδ(2)

Wherein the phase delay of array element in r ' position relative to r position centered by δ, is determined by the beam direction of phased array antenna; K is the wave vector of phased array antenna, and k=2 π/λ, λ are phased array antenna radiation field wavelength in a vacuum, and e is natural logarithm, and j is complex factor, j ²=-1, in phased array antenna subset, the radiated electric field of each array element is respectively E _{r ' 1}, E _{r ' 2}..., E _{r ' N}, according to the relation in electric field and magnetic field, the radiation field H of each array element in phased array antenna subset can be obtained _{r ' 1}, H _{r ' 2}..., H _{r ' N}.

By technique scheme; described step 2) specifically comprise; the ray each array element radiation field of phased array antenna being carried out to diffraction field tracks; solve the diffraction field of each array element radiation lobe one by one according to ray tracing according to consistance diffraction theory, diffraction ray tracks and to solve according to Fermat principle and the diffraction angle character equal with incident angle, after ray tracks and obtains ray tracing; according to consistance diffraction theory; solve diffraction field, under ray basis coordinates system, diffraction electric field is

$\left[\begin{array}{c}{E}_{\left|\right|n}^d\\ E_{\⊥n}^d\end{array}\right]=\left[\begin{array}{cc}-D_{\left|\right|}& 0\\ 0& -D_{\⊥}\end{array}\right]\left[\begin{array}{c}{E}_{\left|\right|n}^i\\ E_{\⊥n}^i\end{array}\right]A\left(s\right)e^{-\mathrm{j\βs}}---\left(3\right)$

Wherein, be the incident field intensity of the n-th array-element antenna radiation field at Diffraction Point, this array element with field intensity be (n=1,2 ..., N), wherein N is total array number of this phased array antenna, D _||, D _⊥for the diffraction field diffraction coefficient in horizontal and vertical direction; for in ray basis coordinates system, calculate the diffraction electric field of impact point, itself and field intensity are (n=1,2 ..., N), A (s) is the spatial attenuation factor, and s is that Diffraction Point arrives the distance calculating impact point, and β is transmission constant.

By technique scheme, described step 3) specifically comprise,

$E_t={\mathrm{Ed}}_1+{\mathrm{Ed}}_2+...+{\mathrm{Ed}}_N=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{Ed}}_i---\left(4\right)$

E _tfor the total diffraction electric field of phased array antenna, Ed ₁, Ed ₂, Ed _nbe respectively the 1st, 2, the diffraction electric field of N number of bay.

By technique scheme, described step 4) specifically comprise, N number of array element superposition of phased array antenna can obtain electric field Ee, the magnetic field Hh of phased array antenna at arbitrary impact point:

$\mathrm{Ee}=E_{r^{\′}1}+E_{r^{\′}2}+...+E_{r^{\′}N}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{E}_{r^{\′}i}$

$\mathrm{Hh}=H_{r^{\′}1}+H_{r^{\′}2}+...+H_{r^{\′}N}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{H}_{r^{\′}i}$

The power P of the phased array antenna radiation based on Ee, Hh ₁for:

$P_1=\frac{1}{2}\mathrm{Re}\left(\underset{S}{\∫}(\mathrm{Ee}\×{\mathrm{Hh}}^{*})\mathrm{dS}\right)---\left(5\right)$

The spherome surface that S is take center of antenna as the centre of sphere, typical radius value is 1000 meters, dS presentation surface differential, ^*represent conjugation, Re represents realistic portion; According to the actual general power P of aerial radiation, electric field correction coefficient is

$k^{\′}=\sqrt{\frac{P}{P_1}}---\left(6\right).$

By technique scheme, described step 5) specifically comprise, the phased array antenna diffraction field after capability correction is

E′ _t＝k′E _t(7)。

The beneficial effect that the present invention produces is: what (1) reduced phased array antenna diffraction field solves difficulty, the phased array antenna near field diffraction being difficult to solve is changed into the far-field diffraction of the array-element antenna being easy to solve, thus existing diffraction theory can be utilized, greatly reduce and solve difficulty.(2) computational accuracy is high, and theoretic preciseness ensure that the accuracy of result of calculation.(3) counting yield is high, and this method is applicable to development computer concurrent program and realizes, even if the phased array antenna of tens thousand of array elements also can obtain result fast.(4) adaptability is good, and this method does not rely on the array element type of phased array antenna, and the planar array antenna based on any type array element all can adopt these computing method to calculate its diffraction field data.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:

Fig. 1 is the process flow diagram of the embodiment of the present invention;

Fig. 2 is the schematic diagram of phased array antenna subset.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

In the embodiment of the present invention, provide a kind of phased array antenna diffraction field computing method.Method of the present invention includes and solves and capability correction two committed steps by first diffraction, and thinking of the present invention is: the diffraction field of phased array antenna radiation field solves and is decomposed into the vector superposed of each array-element antenna diffraction field by a..So just the near field diffraction of phased array antenna is decomposed into the far-field diffraction of array-element antenna.Because current diffraction field theory of solving (consistance diffraction theory, UTD) and formula are based on far field, UTD so just can be utilized to solve diffraction field.B. capability correction is carried out to the superimposed field of array element, thus the diffraction field under solving actual emission power.

As shown in Figure 1, these phased array antenna diffraction field computing method comprise the following steps, and 1) calculate the radiation field of phased array elements in battle array; 2) diffraction field of each array element is solved by first method; 3) vector superposedly phased array antenna diffraction field is solved; 4) radiation field of aerial correction coefficient is solved; 5) the phased array antenna diffraction field after correcting is calculated.

Further, described step 1) specifically comprise, centered by phased array center position, selection length of side is the square of 2 λ, as phased array antenna subset, λ is the electromagnetic wave wavelength in a vacuum of phased array antenna radiation, array element centered by the array element of phased array center position.Center array element applies the excitation (i.e. the excitation of 1 watt) of specific power, other array elements connect matched load, active cell method is adopted to calculate the radiation field of this phased array antenna subset, as the radiation field of center array element, and as the radiation field of each array element in this phased array antenna.As shown in Figure 2, it is the schematic diagram of phased array antenna subset (little battle array), for the partial array geometry numerical value electromagnetic model of 9 × 9 array-element antenna in phased array, array element radiation field is calculated by active cell method, select a little battle array, excitation center array element, other connect matched load, calculate the radiation field of radiation lobe as array element of little battle array.In a limited battle array, when Antenna Operation, array-element antenna is excited simultaneously, and the radiation field of each array element is different.Because the error brought like this is negligible, in the inventive method, think that array element radiation is identical, and get the radiation field of radiation as each array element of center cell in battle array.

Further, when described center array element is r to aiming spot vector, E is the electric field intensity of r Place object point, and center array element at the radiated electric field of r Place object point is,

$r\·E=r{E}_x\hat{x}+r{E}_y\hat{y}+r{E}_z\hat{z}---\left(1\right)$

Wherein, r=|r|, for the direction vector of r, E _x, E _y, E _zfor the three-component of E, be plural number; When impact point spatial position change, as position, then the electric field of r ' position is

E _r′＝r·E/r′·e ^-jkr′·e ^jδ(2)

Wherein the phase delay of array element in r ' position relative to r position centered by δ, is determined by the beam direction of phased array antenna; K is the wave vector of phased array antenna, and k=2 π/λ, λ are phased array antenna radiation field wavelength in a vacuum, and e is natural logarithm, and j is complex factor, j ²=-1.From above formula, as long as determine the rE of a direction, the electric field of this optional position, direction can be obtained very easily.The radiation field of array element centered by the radiation field of little array is also the radiation field of each array element.In phased array antenna subset, the radiated electric field of each array element is respectively E _{r ' 1}, E _{r ' 2}..., E _{r ' N}.According to the relation in electric field and magnetic field, the radiation field H of each array element in phased array antenna subset can be obtained _{r ' 1}, H _{r ' 2}..., H _{r ' N}.

Further, described step 2) specifically comprise, the ray each array element radiation field of phased array antenna being carried out to diffraction field tracks, solve the diffraction field of each array element radiation lobe one by one according to ray tracing according to consistance diffraction theory, the disk construction of metal is typical structure, and this section calculates diffraction field for this kind of entity.Diffraction ray tracks and to solve according to Fermat principle and the diffraction angle character equal with incident angle, and after ray tracks and obtains ray tracing, according to consistance diffraction theory, solve diffraction field, under ray basis coordinates system, diffraction electric field is

$\left[\begin{array}{c}{E}_{\left|\right|n}^d\\ E_{\⊥n}^d\end{array}\right]=\left[\begin{array}{cc}-D_{\left|\right|}& 0\\ 0& -D_{\⊥}\end{array}\right]\left[\begin{array}{c}{E}_{\left|\right|n}^i\\ E_{\⊥n}^i\end{array}\right]A\left(s\right)e^{-\mathrm{j\βs}}---\left(3\right)$

Wherein, be the incident field intensity of the n-th array-element antenna radiation field at Diffraction Point, this array element with field intensity be (n=1,2 ..., N), wherein N is total array number of this phased array antenna, D _||, D _⊥for the diffraction field diffraction coefficient in horizontal and vertical direction; for in ray basis coordinates system, calculate the diffraction electric field of impact point, itself and field intensity are (n=1,2 ..., N), A (s) is the spatial attenuation factor, and s is that Diffraction Point arrives the distance calculating impact point, and β is transmission constant.

Further, described step 3) specifically comprise,

$E_t={\mathrm{Ed}}_1+{\mathrm{Ed}}_2+...+{\mathrm{Ed}}_N=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{Ed}}_i---\left(4\right)$

E _tfor the total diffraction electric field of phased array antenna, Ed ₁, Ed ₂, Ed _nbe respectively the 1st, 2, the diffraction electric field of N number of bay.

Further, obtain the radiation field correction coefficient of phased array antenna under actual emission power according to slope print booth integration, electric field correction is carried out to superimposed field.In formula (2), give the radiation field of array element when 1 watt of power drive, phased array antenna resultant field equals the superposition of each array element radiation field.But directly with radiation field superposition during 1 watt of power drive, the general power after superposition is not N watt, and N is the array element quantity of phased array antenna here.This is because the general power after superposition is specified by Poynting theorem, it not the algebraic sum of each array-element antenna exciting power.Therefore, be the correct radiation field under the radiation of power of realistic border, capability correction need be carried out to the resultant field after superposition.By the real power of phased array antenna radiation, radiation field correction is carried out to superimposed field (4).Described step 4) specifically comprise, N number of array element superposition of phased array antenna can obtain electric field Ee, the magnetic field Hh of phased array antenna at arbitrary impact point:

$\mathrm{Ee}=E_{r^{\′}1}+E_{r^{\′}2}+...+E_{r^{\′}N}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{E}_{r^{\′}i}$

$\mathrm{Hh}=H_{r^{\′}1}+H_{r^{\′}2}+...+H_{r^{\′}N}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{H}_{r^{\′}i}$

The power P of the phased array antenna radiation based on Ee, Hh ₁for:

$P_1=\frac{1}{2}\mathrm{Re}\left(\underset{S}{\∫}(\mathrm{Ee}\×{\mathrm{Hh}}^{*})\mathrm{dS}\right)---\left(5\right)$

The spherome surface that S is take center of antenna as the centre of sphere, typical radius value is 1000 meters, dS presentation surface differential, ^*represent conjugation, Re represents realistic portion; According to the actual general power P of aerial radiation, electric field correction coefficient is

$k^{\′}=\sqrt{\frac{P}{P_1}}---\left(6\right).$

Further, described step 5) specifically comprise, the phased array antenna diffraction field after capability correction is

E′ _t＝k′E _t(7)。

The principle of the invention is: solved the diffraction field of phased array antenna radiation field and be decomposed into the vector superposed of each array-element antenna diffraction field.So just the near field diffraction of phased array antenna is decomposed into the far-field diffraction of array-element antenna.Because current diffraction field theory of solving (consistance diffraction theory, UTD) and formula are based on far field, UTD so just can be utilized to solve diffraction field.Further capability correction is carried out to the superimposed field of array element, thus the phased array antenna diffraction field under solving actual emission power.Thus obtain following beneficial effect: what (1) reduced phased array antenna diffraction field solves difficulty, the phased array antenna near field diffraction being difficult to solve is changed into the far-field diffraction of the array-element antenna being easy to solve, thus existing diffraction theory can be utilized, greatly reduce and solve difficulty.(2) computational accuracy is high, and theoretic preciseness ensure that the accuracy of result of calculation.(3) counting yield is high, and this method is applicable to development computer concurrent program and realizes, even if the phased array antenna of tens thousand of array elements also can obtain result fast.(4) adaptability is good, and this method does not rely on the array element type of phased array antenna, and the planar array antenna based on any type array element all can adopt these computing method to calculate its diffraction field data.

Should be understood that, for those of ordinary skills, can be improved according to the above description or convert, and all these improve and convert the protection domain that all should belong to claims of the present invention.

Claims (7)

1. phased array antenna diffraction field computing method, is characterized in that, the method comprises the following steps, 1) calculate the radiation field of phased array elements in battle array; 2) diffraction field of each array element is solved by first method; 3) vector superposedly phased array antenna diffraction field is solved; 4) radiation field of aerial correction coefficient is solved; 5) the phased array antenna diffraction field after correcting is calculated.

2. phased array antenna diffraction field according to claim 1 computing method, it is characterized in that, described step 1) specifically comprise, centered by phased array center position, selection length of side is the square of 2 λ, as phased array antenna subset, λ is the electromagnetic wave wavelength in a vacuum of phased array antenna radiation, array element centered by the array element of phased array center position, center array element applies the excitation of specific power, other array elements connect matched load, active cell method is adopted to calculate the radiation field of this phased array antenna subset, as the radiation field of center array element, and as the radiation field of each array element in this phased array antenna.

3. phased array antenna diffraction field according to claim 2 computing method, is characterized in that, when described center array element is r to aiming spot vector, E is the electric field intensity of r Place object point, and center array element at the radiated electric field of r Place object point is,

$r\·E={\mathrm{rE}}_x\hat{x}+{\mathrm{rE}}_y\hat{y}+{\mathrm{rE}}_z\hat{z}---\left(1\right)$

Wherein, r=|r|, for the direction vector of r, E _x, E _y, E _zfor the three-component of E,

Be plural number; When impact point spatial position change, as position, then the electric field of r ' position is

E _r′＝r·E/r′·e ^-jkr′·e ^jδ(2)

Wherein the phase delay of array element in r ' position relative to r position centered by δ, is determined by the beam direction of phased array antenna; K is the wave vector of phased array antenna, and k=2 π/λ, λ are phased array antenna radiation field wavelength in a vacuum, and e is natural logarithm, and j is complex factor, j ²=-1, in phased array antenna subset, the radiated electric field of each array element is respectively E _{r ' 1}, E _{r ' 2}..., E _{r ' N}, according to the relation in electric field and magnetic field, the radiation field H of each array element in phased array antenna subset can be obtained _{r ' 1}, H _{r ' 2}..., H _{r ' N}.

4. phased array antenna diffraction field according to claim 3 computing method; it is characterized in that; described step 2) specifically comprise; the ray each array element radiation field of phased array antenna being carried out to diffraction field tracks; solve the diffraction field of each array element radiation lobe one by one according to ray tracing according to consistance diffraction theory; diffraction ray tracks and to solve according to Fermat principle and the diffraction angle character equal with incident angle; after ray tracks and obtains ray tracing; according to consistance diffraction theory; solve diffraction field; under ray basis coordinates system, diffraction electric field is

$\left[\begin{array}{c}{E}_{\left|\right|n}^d\\ E_{\⊥n}^d\end{array}\right]=\left[\begin{array}{cc}-D_{\left|\right|}& 0\\ 0& -D_{\⊥}\end{array}\right]\left[\begin{array}{c}{E}_{\left|\right|n}^i\\ E_{\⊥n}^i\end{array}\right]A\left(s\right)e^{-\mathrm{j\βs}}---\left(3\right)$

Wherein, be the incident field intensity of the n-th array-element antenna radiation field at Diffraction Point, this array element with field intensity be (n=1,2 ..., N), wherein N is total array number of this phased array antenna, D _||, D _⊥for the diffraction field diffraction coefficient in horizontal and vertical direction; for in ray basis coordinates system, calculate the diffraction electric field of impact point, itself and field intensity are (n=1,2 ..., N), A (s) is the spatial attenuation factor, and s is that Diffraction Point arrives the distance calculating impact point, and β is transmission constant.

5. phased array antenna diffraction field according to claim 4 computing method, is characterized in that, described step 3) specifically comprise,

$E_t={\mathrm{Ed}}_1+{\mathrm{Ed}}_2+...+{\mathrm{Ed}}_N=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\mathrm{Ed}}_i---\left(4\right)$

E _tfor the total diffraction electric field of phased array antenna, Ed ₁, Ed ₂, Ed _nbe respectively the 1st, 2, the diffraction electric field of N number of bay.

6. phased array antenna diffraction field according to claim 5 computing method, is characterized in that, described step 4) specifically comprise, N number of array element superposition of phased array antenna can obtain electric field Ee, the magnetic field Hh of phased array antenna at arbitrary impact point:

$\mathrm{Ee}=E_{r^{\′}1}+E_{r^{\′}2}+...+E_{r^{\′}N}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{E}_{r^{\′}i}$

$\mathrm{Hh}=H_{r^{\′}1}+H_{r^{\′}2}+...+H_{r^{\′}N}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{H}_{r^{\′}i}$

The power P of the phased array antenna radiation based on Ee, Hh ₁for:

$P_1=\frac{1}{2}\mathrm{Re}\left(\underset{S}{\∫}(\mathrm{Ee}\×{\mathrm{Hh}}^{*})\mathrm{dS}\right)---\left(5\right)$

The spherome surface that S is take center of antenna as the centre of sphere, typical radius value is 1000 meters, dS presentation surface differential, ^*represent conjugation, Re represents realistic portion; According to the actual general power P of aerial radiation, electric field correction coefficient is

$k^{\′}=\sqrt{\frac{P}{P_1}}---\left(6\right).$

7. phased array antenna diffraction field according to claim 6 computing method, is characterized in that, described step 5) specifically comprise, the phased array antenna diffraction field after capability correction is

E′ _t＝k′E _t(7)。