CN106841825B - Near-field antenna beam control system based on wave-absorbing cavity structure - Google Patents
Near-field antenna beam control system based on wave-absorbing cavity structure Download PDFInfo
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- CN106841825B CN106841825B CN201710002325.7A CN201710002325A CN106841825B CN 106841825 B CN106841825 B CN 106841825B CN 201710002325 A CN201710002325 A CN 201710002325A CN 106841825 B CN106841825 B CN 106841825B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/08—Measuring electromagnetic field characteristics
- G01R29/0864—Measuring electromagnetic field characteristics characterised by constructional or functional features
- G01R29/0878—Sensors; antennas; probes; detectors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
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Abstract
Disclosed is a near field antenna beam control system based on wave-absorbing cavity structure, comprising: the device comprises a rotary table, a target to be detected, a feed source antenna and a wave absorption cavity, wherein the target to be detected is arranged on the rotary table; the wave-absorbing cavity cover is arranged on the periphery of the feed source antenna outside the aperture plane direction and is a semi-closed cavity, the inner wall of the wave-absorbing cavity is provided with a wave-absorbing unit, and one side of the wave-absorbing cavity facing to a target to be measured is provided with an opening; the feed source antenna is arranged in the wave absorbing cavity, and the mouth surface faces the opening direction. The wave absorption cavity is covered on the periphery of the feed source antenna except the direction of the aperture surface, so that the beam control can be performed on the feed source antenna which is designed and processed, the influence of objective factors such as the side lobe of the feed source antenna, the test environment and the like on near-field electromagnetic measurement is reduced, and the test precision is improved; meanwhile, the wave absorbing units are laid in the wave absorbing cavities, so that the laying range of the indoor wave absorbing materials can be reduced in a large area, and the construction cost of the test environment is reduced.
Description
Technical Field
The invention relates to the technical field of electromagnetic measurement, in particular to a near-field antenna beam control system based on a wave-absorbing cavity structure.
Background
The background of the related art of the present invention will be described below, but the description does not necessarily constitute the prior art of the present invention.
The near-field electromagnetic measurement technology is a technology that in a distance of 3-5 wavelengths away from an object, an electrically small antenna (the geometric dimension is far smaller than the wavelength) with known electrical characteristics is used as a feed source, amplitude and phase data of a near-region electromagnetic field of an object to be measured on a plane or a curved surface are scanned and sampled, and the far-region field electrical characteristics of the antenna are calculated through Fast Fourier Transform (FFT). Wherein the fourier transform satisfies the basic formula:
the planar scan sampling satisfies the nyquist sampling theorem, namely:
in recent years, with the rapid development of near-field electromagnetic measurement technology, the characteristics of low cost, high efficiency, unlimited test field, unlimited measurable target size and the like shown by the near-field electromagnetic measurement technology are gradually highlighted, and the application range of the near-field electromagnetic measurement technology is expanded.
In the indoor near-field electromagnetic measurement, the quality of the electrical property of the feed source antenna plays a decisive role in the quality of the measurement result. Generally, in the electromagnetic simulation design stage of the feed antenna, a directional diagram and other related electrical properties of the feed antenna are determined, and once the feed antenna model is processed, the related electrical properties (especially non-ideal electrical properties caused by processing deviation and the like) cannot be adjusted in the later use process; in addition, the existence of objective factors such as antenna side lobe leakage and test environment reflection (as shown in fig. 1a and 1 b) can cause the compact range scattering clutter to be difficult to control, and further cause a certain deviation of the measurement result, which is a problem to be solved in practical engineering application, especially for large-size targets.
Disclosure of Invention
The invention aims to provide a near-field antenna beam control system based on a wave-absorbing cavity structure, which can control beams of a feed antenna which is designed and processed, reduce the influence of objective factors such as side lobes of the feed antenna, a test environment and the like on near-field electromagnetic measurement and has high test precision; the laying range of the indoor wave-absorbing material can be reduced in a large area, and the construction cost of the test environment is reduced.
The invention relates to a near-field antenna beam control system based on a wave-absorbing cavity structure, which comprises: the device comprises a rotary table, a target to be detected and a feed source antenna, wherein the target to be detected is arranged on the rotary table, and the feed source antenna is used for scanning amplitude and phase data of a near-zone electromagnetic field of the target to be detected; characterized in that it further comprises: a wave absorption cavity;
the wave-absorbing cavity cover is arranged on the periphery of the feed source antenna outside the aperture plane direction and is a semi-closed cavity; the inner wall of the wave absorption cavity is provided with a wave absorption unit, and one side of the wave absorption unit, which faces the target to be measured, is provided with an opening; the feed source antenna is arranged in the wave absorbing cavity, and the mouth surface faces the opening direction.
Preferably, the opening is arranged in the center of the side face of the wave absorption cavity, and the feed source antenna is arranged on the axis of the wave absorption cavity passing through the center of the opening.
Preferably, the open hole is wrapped with the wave absorbing unit.
Preferably, the wave absorbing unit is a zigzag structure, and comprises: the wave absorbing base layer is laid on the inner wall of the wave absorbing cavity, and the wave absorbing bulges are arranged on the wave absorbing base layer.
Preferably, the wave-absorbing protrusions are wedge-shaped protrusions or wedges.
Preferably, the wave absorbing unit is laid on each wall surface of the inner wall of the wave absorbing cavity; or, a ray tracing method is adopted to determine the reflection path of the ray emitted by the feed source antenna on the inner wall of the wave-absorbing cavity, and the wave-absorbing unit is laid at the reflection point of the ray on the inner wall of the wave-absorbing cavity.
Preferably, the larger the density of the reflection points is, the larger the thickness of the wave absorbing unit at the corresponding position of the inner wall of the wave absorbing cavity is.
Preferably, the wave absorbing units at different positions of the inner wall of the wave absorbing cavity are different in type; and determining the reflection path of the ray emitted by the feed source antenna on the inner wall of the wave-absorbing cavity by adopting a ray tracing method, wherein the larger the density of the reflection points is, the smaller the reflectivity of the wave-absorbing unit at the corresponding position of the inner wall of the wave-absorbing cavity is.
Preferably, for any position of the inner wall of the wave-absorbing cavity, the thickness of the corresponding wave-absorbing unit satisfies the following relation:
h＝nλ
in the formula, h is the thickness of the wave absorbing unit, and lambda is the wavelength corresponding to the lowest frequency of the near field test, and the unit is m; n is a positive integer and is dimensionless.
The invention relates to a near-field antenna beam control system based on a wave-absorbing cavity structure, which comprises: the device comprises a rotary table, a target to be detected, a feed source antenna and a wave absorption cavity, wherein the target to be detected is arranged on the rotary table; the wave absorbing cavity is a semi-closed cavity, the inner wall of the wave absorbing cavity is provided with a wave absorbing unit, and one side of the wave absorbing cavity facing the target to be measured is provided with an opening; the feed source antenna is arranged in the wave absorbing cavity, and the mouth surface faces the opening direction. The wave absorption cavity is covered on the periphery of the feed source antenna except the direction of the aperture surface, so that the beam control can be performed on the feed source antenna which is designed and processed, the influence of objective factors such as the side lobe of the feed source antenna, the test environment and the like on near-field electromagnetic measurement is reduced, and the test precision is improved; meanwhile, the wave absorbing units are laid in the wave absorbing cavities, so that the laying range of the indoor wave absorbing materials can be reduced in a large area, and the construction cost of the test environment can be reduced.
Drawings
The features and advantages of the present invention will become more readily appreciated from the detailed description section provided below with reference to the drawings, in which:
FIG. 1a is a side view showing a conventional in-room near field measurement;
FIG. 1b is a top view showing a conventional in-room near field measurement;
FIG. 2a is a side view of indoor near field measurement actual measurement of a near field antenna beam control system based on a wave-absorbing cavity structure according to the present invention;
FIG. 2b is a top view of the indoor near field measurement actual measurement of the near field antenna beam control system based on the wave-absorbing cavity structure according to the present invention;
FIG. 3 is a schematic view of the wave-absorbing cavity at the opening of the invention;
FIG. 4 is a schematic structural diagram of a wave-absorbing unit in the invention;
in the figure, 10, a turntable; 20. a near area of a target to be detected; 30. a feed antenna; 40. a wave absorption cavity; 41. opening a hole; 42. the wave absorbing unit, 421, absorb the wave base course; 422. wave-absorbing bulges; 100. an effective radiation boundary of the feed antenna; 200. stray radiation of the feed antenna; 300. indoor test environment; 400. and the wave-absorbing material is paved in an indoor test environment.
Detailed Description
Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The description of the exemplary embodiments is for purposes of illustration only and is not intended to limit the invention, its application, or uses.
In order to control the wave beam of the feed source antenna which is designed and processed, the wave absorbing cavity is covered on the periphery of the feed source antenna except the direction of the aperture surface. As shown in fig. 2a, 2b and 3, the near field antenna beam control system based on the wave-absorbing cavity structure of the present invention includes: the device comprises a rotary table 10, a target to be measured (not shown in the figure) arranged on the rotary table 10, a feed source antenna 30 for scanning amplitude and phase data of a near zone 20 of the target to be measured, and a wave absorption cavity 40; the wave absorption cavity 40 is covered on the periphery of the feed source antenna 30 except the direction of the aperture surface and is a semi-closed cavity, the wave absorption unit 42 is arranged on the inner wall of the wave absorption cavity 40, and an opening 41 is arranged on one side of the wave absorption cavity 40 facing to a target to be measured; the feed antenna 30 is disposed in the wave absorption cavity 40, and the aperture faces the opening 41.
Compared with the traditional indoor near field measurement method, the loading wave absorption cavity 40 can filter radiation of the feed source antenna 30 deviating from the target region direction, so that the feed source wave beam only irradiates the target region, and spatial filtering is realized, thereby enhancing the directivity of the feed source antenna 30, realizing the wave beam control of the feed source antenna 30, and improving the test precision. Meanwhile, the wave absorbing units in the wave absorbing cavity 40 can completely replace wave absorbing materials of the rear wall and part of the side walls of the feed source antenna 40, as shown in fig. 2a and 2b, the usage amount of the wave absorbing materials 400 in the indoor test environment 300 is greatly reduced, and the construction cost of the indoor test environment 300 is reduced.
The person skilled in the art can arrange the opening 41 at the edge of the side of the wave absorption cavity or at the center of the side of the wave absorption cavity according to actual needs, and the position of the opening 41 on the side of the wave absorption cavity does not affect the implementation of the technical solution of the present invention. Preferably, the feed antenna 30 is disposed on the axis of the cavity 40 passing through the center of the opening 41 in order to uniformly filter stray radiation around the feed antenna 30.
The distance between the feed antenna 30 and the opening 41 has an effect on the beam intensity exiting the opening 41. As the distance between the feed antenna 30 and the opening 41 increases, the intensity of the beam exiting the opening 41 decreases. When the distance between the feed antenna 30 and the opening 41 is too large, most of the wave beams emitted by the feed antenna 30 are absorbed by the wave absorbing unit 42 inside the wave absorbing cavity 40, which affects the testing accuracy of the near field test, even the near field test cannot be performed.
The minimum distance between the feed source antenna and the open hole is not particularly limited, and the value can be 0 or a distance value determined according to an error range allowed by a test. The stronger the wave absorbing effect of the wave absorbing unit 42 in the wave absorbing cavity 40, the smaller the lower limit of the distance between the feed source antenna and the opening. In order to prevent as much stray beams in the beam emitted from the feed antenna 30 from exiting the opening 41 without being filtered, and further improve the accuracy and precision of the near field test, the distance between the feed antenna 30 and the opening 41 cannot be too small.
The wave absorbing unit 42 is provided to absorb stray beams of the feed source antenna 30, as long as the wave absorbing unit can achieve the above purpose, and the structure and the laying mode of the wave absorbing unit 42 are not particularly limited. In the preferred embodiment of the present invention, the wave-absorbing unit 42 is a zigzag structure, and includes: a wave-absorbing base layer 421 laid on the inner wall of the wave-absorbing cavity 40, and wave-absorbing protrusions 422 arranged on the wave-absorbing base layer 421, as shown in fig. 4. After the stray waves are incident on the wave absorbing unit 42 with the zigzag shape, the stray waves are continuously reflected and absorbed on the surface of the wave absorbing protrusion 422. In a certain incident angle range, the more the wave absorbing protrusions 422 on the wave absorbing base layer 421 are, the smaller the sharp angle of the wave absorbing protrusions 422 is, the more the ejection times of the stray waves on the surface of the wave absorbing protrusions 422 are, the more the attenuation is, and the better the wave absorbing effect of the wave absorbing unit 42 on the stray waves is. The wave absorbing protrusions 422 can be wedge-shaped protrusions or wedge-shaped protrusions. Of course, the person skilled in the art can select other structural forms of the wave-absorbing protrusion 422 according to the actual requirement. The present invention is not particularly limited in this regard.
In some embodiments of the present invention, the wave absorbing unit 42 is laid on each wall of the inner wall of the wave absorbing cavity 40, so as to sufficiently absorb stray waves in each direction inside the wave absorbing cavity 40. When the emergent direction of the feed source antenna 30 and the structure of the wave absorbing unit 42 are fixed, the reflection point and the emergent direction of the ray in the wave absorbing cavity 40 accord with a certain rule, and the reflection path of the ray in the wave absorbing cavity 40 can be determined by a ray tracing method. Therefore, in other embodiments of the present invention, a ray tracing method may be adopted to determine a reflection path of the radiation emitted by the feed antenna 30 on the inner wall of the wave-absorbing cavity 40, and the wave-absorbing unit 42 is laid at the reflection point of the radiation on the inner wall of the wave-absorbing cavity 40. By adopting the laying mode, stray waves can be effectively filtered, the using amount of the wave absorbing unit 42 can be reduced, and the cost of the wave absorbing cavity 40 is reduced. The greater the density of reflection points, indicating a denser concentration of stray rays there. In order to sufficiently filter out these stray rays, it is preferable that the greater the density of the reflection points, the greater the thickness of the wave absorbing element 42 at the corresponding position on the inner wall of the wave absorbing cavity 40. The wave absorbing units 42 at different positions of the inner wall of the wave absorbing cavity 40 can be of different types, the reflection path of the ray emitted by the feed source antenna on the inner wall of the wave absorbing cavity 40 is determined by adopting a ray tracing method, and the higher the density of the reflection points is, the smaller the reflectivity of the wave absorbing unit 42 at the corresponding position of the inner wall of the wave absorbing cavity 40 is.
The wave absorbing unit 42 can be wrapped at the opening 41, so that the truncation effect at the opening can be weakened, the diffraction effect at the edge of the opening 41 can be reduced, and the flatness of the irradiation amplitude in the target area can be ensured.
In order to improve the filtering effect of the wave absorbing element 42 as much as possible. In some embodiments, for any position of the inner wall of the wave-absorbing cavity 40, the thickness of the corresponding wave-absorbing element 42 satisfies the following relationship:
h＝nλ
in the formula, h is the thickness of the wave absorbing unit, and lambda is the wavelength corresponding to the lowest frequency of the near field test, and the unit is m; n is a positive integer and is dimensionless.
Compared with the prior art, the invention carries out spatial filtering on the irradiation wave beam of the feed source antenna by loading the wave absorption cavity at the periphery outside the aperture plane direction of the feed source antenna, thereby playing the effect of irradiating only a target area and achieving the purposes of improving the test precision and reducing the construction cost.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the specific embodiments described and illustrated in detail herein, and that various changes may be made therein by those skilled in the art without departing from the scope of the invention as defined by the appended claims.
Claims (8)
1. A near field antenna beam control system based on a wave-absorbing cavity structure comprises: the device comprises a rotary table, a target to be detected and a feed source antenna, wherein the target to be detected is arranged on the rotary table, and the feed source antenna is used for scanning amplitude and phase data of a near-zone electromagnetic field of the target to be detected; characterized in that it further comprises: a wave absorption cavity; the wave-absorbing cavity is covered on the periphery outside the aperture plane direction of the feed source antenna and is a semi-closed cavity; the inner wall of the wave absorption cavity is provided with a wave absorption unit, and one side of the wave absorption unit facing the target to be detected is provided with an opening; the wave absorption cavity filters radiation of the feed source antenna deviating from the direction of a target area, so that the feed source wave beam only irradiates the target area, thereby realizing spatial filtering, enhancing the directivity of the feed source antenna and realizing the wave beam control of the feed source antenna; the feed source antenna is arranged in the wave absorbing cavity, and the mouth surface faces the hole opening direction; the feed source antenna is arranged on an axis of the wave absorption cavity passing through the center of the opening so as to uniformly filter stray rays around the feed source antenna; wherein, the wave absorbing unit is wrapped at the open pore.
2. The near field antenna beam steering system of claim 1, wherein the aperture is disposed in a center of a side of the cavity, and the feed antenna is disposed on an axis of the cavity passing through the center of the aperture.
3. The near field antenna beam control system of claim 2, wherein the wave absorbing unit is a saw-tooth structure comprising: the wave absorbing base layer is laid on the inner wall of the wave absorbing cavity, and the wave absorbing bulges are arranged on the wave absorbing base layer.
4. The near field antenna beam steering system of claim 3, wherein the wave absorbing protrusion is a wedge-shaped protrusion or a wedge.
5. The near-field antenna beam control system of claim 3, wherein the wave absorbing elements are laid on each wall surface of the wave absorbing cavity inner wall; or, determining the reflection path of the ray emitted by the feed source antenna on the inner wall of the wave absorbing cavity by adopting a ray tracing method, and laying the wave absorbing unit at the reflection point of the ray on the inner wall of the wave absorbing cavity.
6. The near-field antenna beam control system of claim 5, wherein a ray tracing method is used to determine a reflection path of a ray emitted by the feed source antenna on the inner wall of the wave-absorbing cavity, and the greater the density of reflection points, the greater the thickness of the wave-absorbing unit at a corresponding position of the inner wall of the wave-absorbing cavity.
7. The near field antenna beam control system of claim 5, wherein the wave absorbing elements at different positions of the inner wall of the wave absorbing chamber are of different types; and determining the reflection path of the ray emitted by the feed source antenna on the inner wall of the wave absorbing cavity by adopting a ray tracing method, wherein the higher the density of the reflection points is, the smaller the reflectivity of the wave absorbing unit at the corresponding position of the inner wall of the wave absorbing cavity is.
8. The near-field antenna beam control system of any one of claims 1 to 7, wherein for any position of the inner wall of the wave-absorbing cavity, the thickness of the corresponding wave-absorbing unit satisfies the following relationship:
in the formula, h is the thickness of the wave absorbing unit,
the wavelength corresponding to the lowest frequency of the near field test is in m;
is a positive integer and has no dimension.
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| US10285082B2 (en) * | 2016-11-17 | 2019-05-07 | Rohde & Schwarz Gmbh & Co. Kg | Testing device and method for testing a device under test with respect to its beamforming behavior |
| CN110943305B (en) * | 2018-09-25 | 2023-03-28 | 深圳市中承科技有限公司 | Shielding equipment for wireless test |
| CN113161714A (en) * | 2020-01-22 | 2021-07-23 | 扬博科技股份有限公司 | Shrinkage distance field system for automatic measurement of packaged antenna |
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| CN103630761A (en) * | 2013-11-20 | 2014-03-12 | 中国电子科技集团公司第四十一研究所 | Multi-probe spherical near field channel calibration device and method |
| CN205356355U (en) * | 2015-12-31 | 2016-06-29 | 深圳市通用测试系统有限公司 | Wireless terminal's test system |
| CN105866560A (en) * | 2016-05-06 | 2016-08-17 | 刘本东 | High-performance antenna far-field measurement darkroom and design method |
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| JP2001116784A (en) * | 1999-10-22 | 2001-04-27 | Advantest Corp | Measuring case for radio wave equipment |
| US7940204B1 (en) * | 2009-05-28 | 2011-05-10 | Orbit Advanced Technologies, Inc. | Absorber assembly for an anechoic chamber |
| CN102749529B (en) * | 2011-04-20 | 2015-12-16 | 深圳光启高等理工研究院 | Compact Range antenna measurement system |
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| CN103630761A (en) * | 2013-11-20 | 2014-03-12 | 中国电子科技集团公司第四十一研究所 | Multi-probe spherical near field channel calibration device and method |
| CN205356355U (en) * | 2015-12-31 | 2016-06-29 | 深圳市通用测试系统有限公司 | Wireless terminal's test system |
| CN105866560A (en) * | 2016-05-06 | 2016-08-17 | 刘本东 | High-performance antenna far-field measurement darkroom and design method |
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