CN103424066B - Circular polarized antenna far-field phase difference is utilized to calculate the method for electric field probe rotation offset - Google Patents

Abstract

The present invention relates to a kind of method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset.By setting up electric field probe Xuan and turning Pian Yi ⊿ x with the mathematical model of the ⊿ y linear polarization components far-field phase difference relation orthogonal with circular polarized antenna two, adopt least square method to derive the mathematical calculation model of electric field probe postrotational side-play amount, can get to Jing Que ⊿ x with ⊿ y off-set value.Jiang ⊿ x with ⊿ y side-play amount is used for the compensation of circular polarized antenna near-field test, obtain circular polarized antenna far-field pattern and axial ratio directional diagram accurately.The method does not need to set up heavy optical measuring apparatus and just can obtain electric field probe Xuan and turn Pian Yi ⊿ x with the exact value of ⊿ y, while only needed twice Planar Near-Field Measurement, decrease workload; Electric field probe for measuring only needs can 90-degree rotation, does not require that electric field probe possesses 360 degree of abilities rotated; And the ability of energy auto-compensation electric field probe rotation offset.

Description

Circular polarized antenna far-field phase difference is utilized to calculate the method for electric field probe rotation offset

Technical field

The present invention relates to antenna near-field test technique field, particularly relate to the method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset.

Background technology

Antenna near-field test technique is that a kind of high-precision antenna extensively adopted both at home and abroad is measured and diagnostic techniques.Antenna near-field is divided into induction zone, near field and near field radiation area usually, induction zone, near field is also referred to as reactance near region, energy storage district, its magnetic distribution situation is complicated, needs the amplitude of Measurement accuracy Electric and magnetic fields simultaneously and phase information can calculate the far-field pattern of antenna.When the region leaving antenna to be measured 3 wavelength is exactly near field radiation area, the now impact of inductive near field on antenna measurement is negligible.In near field radiation area, electric field, magnetic field and the direction of propagation are orthogonal, and the ratio of Electric and magnetic fields intensity is the impedance of air, so antenna damnification only needs to carry out to the amplitude of electric field and phase information the far-field pattern that sampling can calculate antenna near field radiation area.

Accurately measure the application scenario of circular polarized antenna far-field pattern and axial ratio in antenna plane near-field test system, planar near-field test macro adopts the high electric field probe of linear polarization purity (as open ended waveguide) measure and calculate circular polarized antenna far-field pattern usually.After the near field amplitude measuring electric field polarization component and phase information, electric field probe half-twist measures near field amplitude and the phase information of another orthogonal linear polarization components.Before and after electric field probe half-twist, its center can offset (decentraction), has partially moved ⊿ x, the distance of ⊿ y.In millimeter wave and submillimeter wave frequency range, its side-play amount can be comparable with wavelength, and now the measuring accuracy of circular polarized antenna far-field pattern and axial ratio can greatly reduce, and test result is even completely invalid.

Probe compensation and fast fourier transform (FFT) are two gordian techniquies of antenna near-field test.Owing to there is not desirable omnidirectional antenna, usually adopt broad beam antenna as electric field probe, need compensating electric field to pop one's head in self directivity characteristics to the impact of test result, just can obtain measurement result accurately.The core technology that probe compensation is tested as antenna near-field, greatly improves the measuring accuracy of antenna radiation pattern.Utilize electric field probe to measure amplitude and the phase information of antenna near-field radiation areas to be measured internal electric field distribution, completed the Near-far fields transfer of antenna by fast fourier transform (FFT), obtain the far-field pattern of antenna.Especially in the far-field pattern measuring circular polarized antenna, after the amplitude normally recording electric field two quadrature linear polarization component near fields and phase information, calculated amplitude and the phase pattern in two quadrature component far fields by the Fourier transform of far to field transformation, then the computing formula carrying it into left-hand circular polarization and right-handed circular polarization component obtains the far field amplitude of circular polarized antenna, phase place and axial ratio directional diagram.

Actual test experience shows: ⊿ x with the side-play amount of ⊿ y is more than 0.2 wavelength, and the far-field pattern of circular polarized antenna and the measuring error of axial ratio are just larger; If more than 1 wavelength, measurement result is invalid.Optimal solution be meet electric field probe rotating concentric requirement ， ⊿ x with ⊿ y is less than 5% of wavelength as far as possible.Due to electric field probe, the processing of radio-frequency module and frock and the accumulation ， ⊿ x of alignment error, can be comparable with the wavelength of millimeter wave and submillimeter wave with ⊿ y side-play amount is difficult to be less than grade.For the planar near-field test of millimeter wave and submillimeter wave frequency range, electric field probe is difficult to the requirement meeting rotating concentric, therefore the impact that the skew that elimination electric field probe rotates ⊿ x and the ⊿ y brought is tested circular polarized antenna far-field pattern is the problem that millimeter wave and submillimeter wave circular polarized antenna planar near-field high-acruracy survey must solve.

In millimeter wave and submillimeter wave frequency range, owing to being difficult to the rotating concentric requirement being met electric field probe by raising machining and installation accuracy, usually adopting the method for optical measurement, obtain electric field probe Xuan Zhuan Hou ⊿ x with the side-play amount of ⊿ y.Then use it for the compensation calculating circular polarized antenna far-field pattern, obtain circular polarized antenna far-field pattern accurately, its cost needs the heavy optical measuring apparatus of erection to complete accurate position measurement.

Also has a kind of comparatively novel method: utilize linear polarized antenna to calibrate electric field probe and rotate Hou ⊿ x with ⊿ y side-play amount, then use it for the compensation of circular polarized antenna far-field pattern.Linear polarized antenna is placed as horizontal polarization by the method, and electric field probe is also placed as horizontal polarization, measures the far field amplitude and the phase pattern that obtain antenna horizontal polarization; Then electric field probe is rotated 180 °, measure the other one group of far field amplitude and the phase pattern that obtain antenna horizontal polarization.The far field amplitude of these two groups of data is completely the same, and far-field phase is except the solid phase potential difference having 180 °, and also Cun ⊿ x offsets the phase differential introduced: thus can the side-play amount of Ji Suan Chu ⊿ x.Linear polarized antenna is placed as vertical polarization, adopts similar method can the side-play amount of get Dao ⊿ y.

The method do not need to set up heavy optical measuring apparatus just can get Dao ⊿ x with the exact value that offsets of ⊿ y, but the subject matter of existence has: 1) needed four near field measurement tasks, workload is very big; 2) partial electric-field is popped one's head in the rotation that can not realize within the scope of 360 °; 3) do not possess auto-compensation Yuan and polarize Tian Xian ⊿ x with the ability of ⊿ y skew.

Summary of the invention

For solve in prior art measure electric field probe and rotate Hou ⊿ x He the side-play amount of ⊿ y time the above-mentioned technical matters that exists, of the present inventionly provide a kind of method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset, by setting up the mathematical model of circular polarized antenna far-field phase difference and electric field probe rotation offset, accurate measurement also calculates electric field probe and rotates the ⊿ x and ⊿ y side-play amount that bring, eliminate it measures circular polarized antenna far-field pattern impact on planar near-field test macro, improve the measuring accuracy of circular polarized antenna axial ratio and far-field pattern.

For achieving the above object, of the present inventionly provide a kind of method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset, the method comprises:

Step 1) utilize the electric field probe of planar near-field test macro to measure near field amplitude and the phase place of the orthogonal linear polarization components of two of circular polarized antenna;

Step 2) the near field amplitude of utilize step 1 to obtain two orthogonal linear polarization components and phase place by the Fourier transform of far to field transformation, calculate far field amplitude and the phase differential of described two orthogonal linear polarization components;

Step 3) set up electric field probe rotation offset and step 2) in calculate two orthogonal linear polarization components far-field phase difference between the mathematical model of relation, the computing formula of described mathematical model is as follows:

$\mathrm{\Δ}\mathrm{\φ}={\mathrm{\φ}}_{el}(\mathrm{\θ},\mathrm{\φ})-{\mathrm{\φ}}_{az}(\mathrm{\θ},\mathrm{\φ})={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}(\mathrm{\θ},\mathrm{\φ})-{\mathrm{\φ}}_{az}\left(\mathrm{\θ},\mathrm{\φ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}(\mathrm{\Δ}xsin\mathrm{\θ}cos\mathrm{\φ}+\mathrm{\Δ}ysin\mathrm{\θ}\sin \mathrm{\φ})$ Formula 7

Wherein, Δ φ is that the far-field phase of described two orthogonal linear polarization components is poor, φ _az(θ, φ) represents that electric field probe is at the far-field phase directional diagram rotating the linear polarization components that pre-test obtains, φ _el(θ, φ) represents that electric field probe offsets the far-field phase directional diagram of the linear polarization components obtained after half-twist, the far-field phase directional diagram ⊿ x that the linear polarization components obtained occurs to offset expression electric field probe after half-twist represents that electric field probe postrotational horizontal position offset amount ⊿ y represents the postrotational vertical position offset amount of electric field probe, θ and φ represents the angle of pitch and the position angle of spherical coordinate system respectively;

Step 4) adopt least square method to derive the mathematical calculation model of the postrotational side-play amount of electric field probe, obtain electric field probe Xuan and turn Pian Yi ⊿ x with ⊿ y, the computing formula of described mathematical calculation model is as follows:

$\mathrm{\Δ}x=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 10

$\mathrm{\Δ}y=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 11

Wherein, the expression angle of pitch is θ _mthe far-field phase of the linear polarization components that two of angle are orthogonal is poor.

As the further improvement of technique scheme, described step 3) formula 7 in choose the tangent plane of φ=0 °, the namely azimuth plane of circular polarized antenna far-field pattern, then formula 7 is reduced to formula 8,

${\mathrm{\φ}}_{el}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}xsin\mathrm{\θ}$ Formula 8

Represent that Zhi You ⊿ x can have an impact to the far-field phase difference of two orthogonal linear polarization components,

Choose the tangent plane of φ=90 ° in described formula 7, the namely pitching face of circular polarized antenna far-field pattern, formula 7 is reduced to formula 9,

${\mathrm{\φ}}_{el}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}y\sin \mathrm{\θ}$ Formula 9

Represent that Zhi You ⊿ y can have an impact to the far-field phase difference of two orthogonal linear polarization components.

As the further improvement of technique scheme, described electric field probe adopts the antenna that linear polarization purity is high.

As the further improvement of technique scheme, described circular polarized antenna adopts the identical multimode horn of the Aperture field distribution of two quadrature linear polarization components or corrugated horn; Can accurately calculate electric field probe rotation offset value, the electric field probe rotation offset value obtained may be used for the compensation of any circular polarized antenna Planar Near-Field Measurement result.

The advantage utilizing circular polarized antenna far-field phase difference to calculate the method for electric field probe rotation offset of the present invention is: by setting up electric field probe Xuan and turning Pian Yi ⊿ x with the mathematical model of the ⊿ y linear polarization components far-field phase poor relation orthogonal with circular polarized antenna two, adopt least square method to derive the mathematical calculation model of electric field probe postrotational side-play amount, can get to Jing Que ⊿ x with ⊿ y off-set value.Jiang ⊿ x with ⊿ y side-play amount is used for the compensation of circular polarized antenna near-field test, thus circular polarized antenna far-field pattern and axial ratio directional diagram accurately can be obtained.The method does not need to set up heavy optical measuring apparatus and just can obtain electric field probe Xuan and turn Pian Yi ⊿ x with the exact value of ⊿ y, while only needed twice Planar Near-Field Measurement, decrease workload; Electric field probe for measuring only needs can 90-degree rotation, does not require that electric field probe possesses 360 degree of abilities rotated; Described circular polarized antenna adopts the identical multimode horn of the Aperture field distribution of two quadrature linear polarization components or corrugated horn, the ability of energy auto-compensation electric field probe rotation offset.

Accompanying drawing explanation

Fig. 1 be the electric field probe of planar near-field test macro in the embodiment of the present invention before and after half-twist, the schematic diagram of its Centre position deviation.

Fig. 2 utilizes the electric field probe of trying to achieve postrotational horizontal position offset Liang ⊿ x in the embodiment of the present invention, the far-field phase directional diagram carrying out circular polarized antenna compensates the contrast schematic diagram of front and back.

Fig. 3 utilizes the electric field probe of trying to achieve postrotational horizontal position offset Liang ⊿ x in the embodiment of the present invention, carry out the contrast schematic diagram before and after circular polarized antenna axial ratio directional diagram and far-field pattern compensation.

Fig. 4 is the process flow diagram utilizing circular polarized antenna far-field phase difference to calculate the method for electric field probe rotation offset of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the invention will be further described and be achieved by following technical proposals.

In order to describe the method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset of the present invention in detail, first, the relation between sonde response and antenna spectrum function to be measured is obtained according to the plane wave coupled matrix theory of Kerns:

$b_0^{\′}(x,y,d)=a_0{F}^{\′}\∫\∫\stackrel{\‾}{t_{10}}\left(\stackrel{\‾}{K}\right)\·{\stackrel{\‾}{S_{02}}}^{\′}\left(\stackrel{\‾}{K}\right)\·e^{j\mathrm{\γ}d}\·e^{j\left(k_{x}x+k_{y}y\right)}{\mathrm{dk}}_x{\mathrm{dk}}_y$ Formula 1

In equation 1: b' ₀the near field amplitude that (x, y, d) is electric field probe and phase output, a ₀for amplitude and the phase place input of antenna to be measured, F' is the impedance mismatching factor, with be respectively antenna transmission spectrum function to be measured and electric-field probe reception spectrum function; X and y is the position at electric-field probe range sweep center in the plane of scanning motion.

When measuring the orthogonal linear polarization components of two of circular polarized antenna, what formula 1 described is the situation that electric field probe half-twist does not occur when offseting.When skew occurs electric field probe half-twist, formula 1 is transformed to following formula:

$b_0^{\′}(x+\mathrm{\Δ}x,y+\mathrm{\Δ}y,d)=a_0{F}^{\′}\∫\∫\stackrel{\‾}{t_{10}}\left(\stackrel{\‾}{K}\right)\·{\stackrel{\‾}{S_{02}}}^{\′}\left(\stackrel{\‾}{K}\right)\·e^{j\mathrm{\γ}d}\·e^{j\left(k_x\left(x+\mathrm{\Δ}x\right)+k_y\left(y+\mathrm{\Δ}y\right)\right)}{\mathrm{dk}}_x{\mathrm{dk}}_y$ Formula 2

By formula 1 and formula 2, can obtain:

$b_0^{\′}(x+\mathrm{\Δ}x,y+\mathrm{\Δ}y,d)=b_0^{\′}(x,y,d)\·e^{j(k_x\mathrm{\Δ}x+k_y\mathrm{\Δ}y)}$ Formula 3

Formula 3 clearly illustrates that: electric field probe half-twist skew does not occur and skew occurs for antenna plane near-field test, and the near field amplitude of the linear polarization components that electric field probe measurement obtains is constant, and near filed phase adds fixed value.

In antenna plane near-field test theory, Antenna Far Field directional diagram and antenna spectrum function are equivalents.Namely the Antenna Far Field directional diagram represented and b' ₀the near field amplitude of the electric field probe that (x, y, d) represents and phase output are Fourier transform relations.In antenna plane near-field test, usually get d=0, namely the plane of scanning motion is that the plane of z=0 is to facilitate the discussion of problem.Therefore, Antenna Far Field directional diagram can be obtained by the inverse Fourier transform of formula 1:

$\stackrel{\‾}{t_{10}}\left(\stackrel{\‾}{K}\right)\·{\stackrel{\‾}{S_{02}}}^{\′}\left(\stackrel{\‾}{K}\right)=\frac{1}{4{\mathrm{\πa}}_0{F}^{\′}}\∫\∫b_0^{\′}(x,y)e^{j(k_{x}x+k_{y}y)}dxdy$ Formula 4

Under normal circumstances, the electric field probe far-field pattern that antenna plane near-field test system uses is known, could carry out probe compensation, obtain antenna to be measured far-field pattern accurately in formula 4.The Antenna Far Field directional diagram that formula 4 obtains is the situation that electric field probe half-twist does not occur when offseting; When skew occurs electric field probe half-twist time, can formula 3 be brought into formula 4, obtain the Antenna Far Field directional diagram that skew occurs for it.From formula 5: electric field probe half-twist skew does not occur compared with generation skew, and the amplitude of the Antenna Far Field directional diagram calculated is constant, and phase place adds fixed value.

$\begin{array}{c}{\[\stackrel{\‾}{t_{10}}\left(\stackrel{\‾}{K}\right)\·{\stackrel{\‾}{S_{02}}}^{\′}\left(\stackrel{\‾}{K}\right)\]}_{\mathrm{\Δ}x,\mathrm{\Δ}y}=\frac{1}{4{\mathrm{\πa}}_0{F}^{\′}}\∫\∫b_0^{\′}\left(x+\mathrm{\Δ}x,y+\mathrm{\Δ}y\right)e^{j(k_{x}x+k_{y}y)}dxdy\\ =\[\frac{1}{4{\mathrm{\πa}}_0{F}^{\′}}\∫\∫b_0^{\′}\left(x,y\right)e^{j(k_{x}x+k_{y}y)}dxdy\]\·e^{j(k_x\mathrm{\Δ}x+k_y\mathrm{\Δ}y)}=\[\stackrel{\‾}{t_{10}}\left(\stackrel{\‾}{K}\right)\·{\stackrel{\‾}{S_{02}}}^{\′}\left(\stackrel{\‾}{K}\right)\]\·e^{j(k_x\mathrm{\Δ}x+k_y\mathrm{\Δ}y)}\end{array}$ Formula 5

As shown in Figure 4, the present invention calculates the far field amplitude of this polarization components and the formula of phase pattern by the near field amplitude and phase data utilizing the orthogonal linear polarization components of above-mentioned circular polarized antenna, there is provided a kind of method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset, the method comprises:

Step 1) utilize the electric field probe of planar near-field test macro to measure near field amplitude and the phase place of the orthogonal linear polarization components of two of circular polarized antenna;

Step 2) the near field amplitude of utilize step 1 to obtain two orthogonal linear polarization components and phase place by the Fourier transform of far to field transformation, calculate far field amplitude and the phase differential of described two orthogonal linear polarization components;

Step 3) set up electric field probe rotation offset and step 2) in calculate two orthogonal linear polarization components circular polarized antenna far-field phase difference between the mathematical model of relation, the computing formula of described mathematical model is as follows:

$\mathrm{\Δ}\mathrm{\φ}={\mathrm{\φ}}_{el}\left(\mathrm{\θ},\mathrm{\φ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ},\mathrm{\φ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ},\mathrm{\φ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ},\mathrm{\φ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\left(\mathrm{\Δ}x\sin \mathrm{\θ}\cos \mathrm{\φ}+\mathrm{\Δ}y\sin \mathrm{\θ}\sin \mathrm{\φ}\right)$ Formula 7

Wherein, Δ φ is that the far-field phase of described two orthogonal linear polarization components is poor, φ _az(θ, φ) represents that electric field probe is at the far-field phase directional diagram rotating the linear polarization components that pre-test obtains, φ _el(θ, φ) represents that electric field probe offsets the far-field phase directional diagram of the linear polarization components obtained after half-twist, the far-field phase directional diagram ⊿ x that the linear polarization components obtained occurs to offset expression electric field probe after half-twist represents that electric field probe postrotational horizontal position offset amount ⊿ y represents the postrotational vertical position offset amount of electric field probe, θ and φ represents the angle of pitch and the position angle of spherical coordinate system respectively;

Step 4) adopt least square method to derive the mathematical calculation model of the postrotational side-play amount of electric field probe, obtain electric field probe Xuan and turn Pian Yi ⊿ x with ⊿ y, the computing formula of described mathematical calculation model is as follows:

$\mathrm{\Δ}x=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 10

$\mathrm{\Δ}y=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 11

Wherein, the expression angle of pitch is θ _mthe far-field phase of the linear polarization components that two of angle are orthogonal is poor.

Based on the above-mentioned method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset, described step 3 in embodiments of the present invention) computation process comprise following content:

Because electric field probe skew does not occur after half-twist compared with generation skew, the amplitude of the circular polarized antenna far-field pattern calculated is constant, and phase place adds fixed value, consider with the fixed value that the circular polarized antenna far-field pattern phase place increase caused occurs after electric field probe half-twist to offset is described as:

${\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}(\mathrm{\θ},\mathrm{\φ})-{\mathrm{\φ}}_{el}(\mathrm{\θ},\mathrm{\φ})=\frac{2\mathrm{\π}}{\mathrm{\λ}}(\mathrm{\Δ}xsin\mathrm{\θ}cos\mathrm{\φ}+\mathrm{\Δ}y\sin \mathrm{\θ}sin\mathrm{\φ})$ Formula 6

Wherein, φ _el(θ, φ) represents that electric field probe offsets the far-field phase directional diagram of the linear polarization components obtained after half-twist, the far-field phase directional diagram ， ⊿ x that the linear polarization components obtained occurs to offset expression electric field probe after half-twist represents that electric field probe postrotational horizontal position offset Liang ， ⊿ y represents the postrotational vertical position offset amount of electric field probe,

The far-field phase difference of described two orthogonal linear polarization components is expressed as: Δ φ=φ _el(θ, φ)-φ _az(θ, φ), and substitute into formula 6,

Then have:

${\mathrm{\φ}}_{el}\left(\mathrm{\θ},\mathrm{\φ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ},\mathrm{\φ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ},\mathrm{\φ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ},\mathrm{\φ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\left(\mathrm{\Δ}x\sin \mathrm{\θ}\cos \mathrm{\φ}+\mathrm{\Δ}y\sin \mathrm{\θ}\sin \mathrm{\φ}\right)$ Formula 7

Wherein, φ _az(θ, φ) represents that electric field probe is at the far-field phase directional diagram rotating the linear polarization components that pre-test obtains,

Choose the tangent plane of φ=0 ° in described formula 7, the namely azimuth plane of circular polarized antenna far-field pattern, then formula 7 is reduced to formula 8,

${\mathrm{\φ}}_{el}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}xsin\mathrm{\θ}$ Formula 8

Represent that Zhi You ⊿ x can have an impact to the far-field phase difference of two orthogonal linear polarization components,

Choose the tangent plane of φ=90 ° in described formula 7, the namely pitching face of circular polarized antenna far-field pattern, formula 7 is reduced to formula 9,

${\mathrm{\φ}}_{el}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}ysin\mathrm{\θ}$ Formula 9

Represent that Zhi You ⊿ y can have an impact to the far-field phase difference of two orthogonal linear polarization components;

Utilize above-mentioned choose circular polarized antenna far-field pattern azimuth plane and pitching face carry out the method measured, Qiu Xie ⊿ x can be distinguished very easily with ⊿ y.

Based on the above-mentioned method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset, described step 4 in embodiments of the present invention) computation process comprise following content:

The far-field phase difference φ of the linear polarization components that circular polarized antenna two is orthogonal _el(θ)-φ _az(θ) close to pi/2 or 3 pi/2s, corresponding left-hand circular polarization and right-handed circular polarization component respectively.For convenience of description, only phase differential being discussed is the situation of pi/2.Because electric field probe is after half-twist, the nearly pi/2 of far-field phase differential of the linear polarization components that two of circular polarized antenna are orthogonal, adopts least square method solution formula get its minimum value and substitute into formula 8 and formula 9, then have:

with get its minimal value, and respectively to △ x and △ y differentiate, then have:

$\mathrm{\Δ}x=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 10

$\mathrm{\Δ}y=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 11

Wherein, represent θ _mthe far-field phase of the linear polarization components that two of angle are orthogonal is poor.

In addition, described electric field probe can adopt the antenna that linear polarization purity is high; The identical circular polarized antenna of Aperture field distribution for two quadrature linear polarization components (as multimode horn, corrugated horn etc.), extra test Biao is not needed to Ding ⊿ x with ⊿ y side-play amount, there is Zi and move Bu Chang ⊿ x with the function of ⊿ y skew, therefore described circular polarized antenna is preferably the identical multimode horn of Aperture field distribution or the corrugated horn of two quadrature linear polarization components.

As shown in Figure 2, be the actual test result before and after the far-field phase directional diagram compensation of 53GHz circular polarisation corrugated horn.To choose the tangent plane of φ=0 °, the far-field phase directional diagram before compensating is shown in Fig. 2 (a), due to electric field probe rotation offset, the phase difference of the far-field phase directional diagram of two quadrature linear polarization components of circular polarized antenna _el(θ)-φ _az(θ) do not meet the condition of pi/2, exist on the impact of phase place; Utilize circular polarized antenna far-field phase difference to calculate the method for electric field probe rotation offset, in the hope of △ x=-4.0186mm, far-field phase formula can be substituted into by formula 10 obtain φ _el(θ) and phase difference _el(θ)-φ _az(θ).Far-field phase directional diagram after compensating is shown in Fig. 2 (b), owing to eliminating on the impact of phase place, meet the phase difference after compensation well _el(θ)-φ _az(θ) close to the condition of pi/2.Result before and after compensating reflects the impact of using and this method eliminateing electric field probe rotation offset and measuring circular polarized antenna.

Being used for Near-field Data compensation by solving the Pian Yi ⊿ x obtained, also can being directly used in the compensation of far-field pattern.As the far field amplitude E of two quadrature linear polarization components of circular polarized antenna _a, E _elwith the phase differential after compensation time known, accurately can be calculated the amplitude of the axial ratio directional diagram of circular polarized antenna, left-hand circular polarization and right-handed circular polarization component by formula 12, formula 13 and formula 14.

$AR=\left|\frac{E_{az}^2+E_{el}^2+\sqrt{{\left(E_{az}^2+E_{el}^2\right)}^2-4E_{az}^2{E}_{el}^2{\cos }^2\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}xsin\mathrm{\θ}-\frac{\mathrm{\π}}{2}\right)}}{2E_{az}{E}_{el}cos\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}xsin\mathrm{\θ}-\frac{\mathrm{\π}}{2}\right)}\right|$ Formula 12

${\stackrel{\‾}{E}}_{LHCP}=\frac{\sqrt{2}}{2}\sqrt{E_{az}^2+E_{el}^2+2E_{az}{E}_{el}cos\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}x\sin \mathrm{\θ}-\frac{\mathrm{\π}}{2}\right)}$ Formula 13

${\stackrel{\‾}{E}}_{RHCP}=\frac{\sqrt{2}}{2}\sqrt{E_{az}^2+E_{el}^2+2E_{az}{E}_{el}cos\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}x\sin \mathrm{\θ}-\frac{3\mathrm{\π}}{2}\right)}$ Formula 14

As shown in Figure 3, for solve obtain electric field probe postrotational horizontal position offset amount △ x=-4.0186mm ⊿ x is used for far field data compensate before and after axial ratio directional diagram and far-field pattern, the measuring accuracy that the result before and after compensating reflects circular polarized antenna axial ratio directional diagram and far-field pattern obtains obvious improvement.

It should be noted last that, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted.Although with reference to embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, modify to technical scheme of the present invention or equivalent replacement, do not depart from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.

Claims (4)

1. utilize circular polarized antenna far-field phase difference to calculate the method for electric field probe rotation offset, the method comprises:

Step 1) utilize the electric field probe of planar near-field test macro to measure near field amplitude and the phase place of the orthogonal linear polarization components of two of circular polarized antenna;

Step 2) the near field amplitude of utilize step 1 to obtain two orthogonal linear polarization components and phase place by the Fourier transform of far to field transformation, calculate far field amplitude and the phase differential of described two orthogonal linear polarization components;

Step 3) set up electric field probe rotation offset and step 2) in calculate two orthogonal linear polarization components far-field phase difference between the mathematical model of relation, the computing formula of described mathematical model is as follows:

$\mathrm{\Δ}\mathrm{\φ}={\mathrm{\φ}}_{el}(\mathrm{\θ},\mathrm{\φ})-{\mathrm{\φ}}_{az}(\mathrm{\θ},\mathrm{\φ})={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}(\mathrm{\θ},\mathrm{\φ})-{\mathrm{\φ}}_{az}(\mathrm{\θ},\mathrm{\φ})-\frac{2\mathrm{\π}}{\mathrm{\λ}}(\mathrm{\Δ}xsin\mathrm{\θ}cos\mathrm{\φ}+\mathrm{\Δ}ysin\mathrm{\θ}sin\mathrm{\φ})$ Formula 7

Wherein, Δ φ is that the far-field phase of described two orthogonal linear polarization components is poor, φ _az(θ, φ) represents that electric field probe is at the far-field phase directional diagram rotating the linear polarization components that pre-test obtains, φ _el(θ, φ) represents that electric field probe offsets the far-field phase directional diagram of the linear polarization components obtained after half-twist, the far-field phase directional diagram ⊿ x that the linear polarization components obtained occurs to offset expression electric field probe after half-twist represents that electric field probe postrotational horizontal position offset amount ⊿ y represents the postrotational vertical position offset amount of electric field probe, θ and φ represents the angle of pitch and the position angle of spherical coordinate system respectively;

Step 4) adopt least square method to derive the mathematical calculation model of the postrotational side-play amount of electric field probe, obtain electric field probe Xuan and turn Pian Yi ⊿ x with ⊿ y, the computing formula of described mathematical calculation model is as follows:

$\mathrm{\Δ}x=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 10

$\mathrm{\Δ}y=\frac{\mathrm{\λ}\underset{m}{\Σ}\left({\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left({\mathrm{\θ}}_m\right)-{\mathrm{\φ}}_{az}\left({\mathrm{\θ}}_m\right)-\frac{\mathrm{\π}}{2}\right){\mathrm{sin\θ}}_m}{2\mathrm{\π}\underset{m}{\Σ}{\sin }^2{\mathrm{\θ}}_m}$ Formula 11

Wherein, the expression angle of pitch is θ _mthe far-field phase of the linear polarization components that two of angle are orthogonal is poor.

2. the method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset according to claim 1, it is characterized in that, described step 3) formula 7 in choose the tangent plane of φ=0 °, the namely azimuth plane of circular polarized antenna far-field pattern, then formula 7 is reduced to formula 8

${\mathrm{\φ}}_{el}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}x\sin \mathrm{\θ}$ Formula 8

Represent that Zhi You ⊿ x can have an impact to the far-field phase difference of two orthogonal linear polarization components,

Choose the tangent plane of φ=90 ° in described formula 7, the namely pitching face of circular polarized antenna far-field pattern, formula 7 is reduced to formula 9,

${\mathrm{\φ}}_{el}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)={\mathrm{\φ}}_{{\mathrm{el}}_{\mathrm{\Δ}x,\mathrm{\Δ}y}}\left(\mathrm{\θ}\right)-{\mathrm{\φ}}_{az}\left(\mathrm{\θ}\right)-\frac{2\mathrm{\π}}{\mathrm{\λ}}\mathrm{\Δ}ysin\mathrm{\θ}$ Formula 9

Represent that Zhi You ⊿ y can have an impact to the far-field phase difference of two orthogonal linear polarization components.

3. the method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset according to claim 1, it is characterized in that, described electric field probe adopts the antenna that linear polarization purity is high.

4. the method utilizing circular polarized antenna far-field phase difference to calculate electric field probe rotation offset according to claim 1, it is characterized in that, described circular polarized antenna adopts the identical multimode horn of the Aperture field distribution of two quadrature linear polarization components or corrugated horn.