CN101149417B - Screen performance test method for veneer with built-in electromagnetic layer - Google Patents
Screen performance test method for veneer with built-in electromagnetic layer Download PDFInfo
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- CN101149417B CN101149417B CN 200710177338 CN200710177338A CN101149417B CN 101149417 B CN101149417 B CN 101149417B CN 200710177338 CN200710177338 CN 200710177338 CN 200710177338 A CN200710177338 A CN 200710177338A CN 101149417 B CN101149417 B CN 101149417B
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Abstract
This invention disclose a kind of plywood shield efficiency coaxial test method, this test method bases on exist coaxial line test method, makes the electromagnetic shielding layer in the sample electric connects the external conductor and the inner conductor nicely by covering the conducted material in the sample surface, to overcome the problem produced by the over-big contact resistance between the test instrument and the sample in exist method, provides technology safeguard for the electromagnetic shielding effect of the test sample .
Description
Technical field
The present invention relates to the coaxial method of testing of a kind of scale board shield effectiveness, especially a kind of electro-magnetic screen layer is arranged on the coaxial method of testing of scale board shield effectiveness that inside and upper and lower surface all insulate.
Background technology
Along with the development of electromagnetic compatibility technology, various novel shielding materials are developed, and develop into the compound substance of present tinsel yarn fabric, metal fibre filled plastics, plated film plastics, coated glass and lamination form etc. from original simple metal material.The performance index of shielding material are generally represented with shield effectiveness, the ability of this index reflection shielding material shielding electromagnetic wave.Shield effectiveness obtains with the test of measuring methods such as screened room window technique, spherical dipole antenna method, coaxial axis method usually, and wherein coaxial axis method is according to SJ 20524-1995 " the shield effectiveness measuring method of material ".It generally is 100kHz～1.5GHz that coaxial axis method is measured frequency range, and this method measurement data is accurate, and measuring repeatability is good, adopts this method at the following measurement plane material of 1.5GHz shield effectiveness usually more.
The coaxial cable method of testing is to utilize the coaxial proving installation of shielding material shown in Figure 1 that the far field electromagnetic shielding properties of scale board shielding material is tested, this proving installation is made of two sections coaxial inner and outer conductor, the inner and outer conductor xsect is circle, the outer conductor of two sections coaxial cables connects by helicitic texture, inner wire reliably is connected (if tested sample is a good conductor by the center pit of bolt tongue and tested sample, then the sample center can not perforate), to guarantee in the test frequency range even, the stable transverse electromagnetic wave of transmission between the coaxial cable inner and outer conductor.Tested sample places between two sections coaxial cables, is obtained the electromagnet shield effect value of shielding material by the difference power value between coaxial device input, the output port.
The equivalent circuit diagram of coaxial axis method test philosophy as shown in Figure 2, wherein: Z
OCharacteristic impedance for transmission line; Z
lBe the sample impedance; Z
CContact impedance for sample and transmission line.
Through to equivalent circuit analysis as can be known, electromagnet shield effect value SE can be determined by following formula:
When testing,, require Z for guaranteeing precision of test result according to routine
C＜＜Z
L, so following formula can be reduced to:
From coaxial axis method test philosophy figure as can be seen, the contact impedance Z between tested sample and coaxial proving installation internal and external conductor
CAffect the accuracy of test.
When adopting coaxial axis method that screen layer is arranged on inner sample, when the scale board that inside as shown in Figure 3 has a screen layer was tested, because the scale board two-layer wood single-plate that is up and down, its surface can be considered insulation, i.e. Z
C＞＞Z
L, middle electro-magnetic screen layer can't realize that good electrical is connected with the internal and external conductor of coaxial proving installation, this moment, the electromagnet shield effect value of scale board became:
Its equivalent electrical circuit as shown in Figure 4.Z among the figure
C1The contact impedance of expression inner wire and sample, Z
C2, Z
C3The contact impedance of expression outer conductor and sample, these impedances can be regarded the combination of capacitive reactances, inductance and resistance as.
By circuit knowledge as can be known, because the existence of capacitive reactances, there is resonance in this equivalent circuit, and on resonant frequency point, it is minimum that contact impedance Z reaches, and this moment, sample shield effectiveness value reached maximal value.Beyond resonant frequency point, contact impedance is bigger, and its shield effectiveness value will be lower than the real test value of material.That is to say the increase along with test frequency, material shield effectiveness value suddenly increases the back earlier and suddenly subtracts, and a spike will occur.This analysis result has obtained good embodiment in actual test result shown in Figure 5, a spike has appearred in electromagnet shield effect curve that this actual test obtains, and its value increases the back and suddenly subtracts along with the increase of wave frequency is anxious earlier.
Therefore, according to above-mentioned analysis as can be known, when screen layer being positioned at inner sample and testing, because the contact resistance between proving installation and the tested sample is excessive according to the conventionally test mode, have a strong impact on precision of test result, can not truly reflect the shield effectiveness that material itself is actual.
Summary of the invention
At the problem that prior art exists, the coaxial method of testing of scale board shield effectiveness that provides a kind of inside to be provided with electro-magnetic screen layer is provided order of the present invention.
For achieving the above object, method of testing of the present invention is specially: at first, make sample by the mode identical with existing coaxial cable method of testing, this sample has the test center pit; Then, electrically-conducting paint is coated on the sample outer circumference surface and the center pit hole wall on, and utilize electrically-conducting paint respectively to apply two consistent with the internal and external conductor face size of coaxial proving installation respectively ring-type conductive coatings in the sample both side surface, wherein outside ring-type conductive coating is electrically connected with the screen layer of sample inside by the electrically-conducting paint that applies on the sample outer circumference surface, and inboard ring-type conductive coating is electrically connected with the screen layer of sample inside by the electrically-conducting paint that applies on the sample center pit hole wall; At last, the existing coaxial cable proving installation of utilization is finished the test to the sample shield effectiveness, be installed in the sample electrically-conducting paint by applying on its lip-deep ring-type conductive coating and the center hole wall respectively on the proving installation, make its inner screen layer realize with proving installation in outer conductor and the good electrical of inner wire be connected.
Method of testing of the present invention is by behind coated with conductive coating on sample both side surface and the center hole wall, make outer conductor and inner wire in the proving installation all realize good being electrically connected with the electro-magnetic screen layer of sample inside, thereby overcome existing method because of the excessive problem of bringing of the contact resistance between proving installation and the sample, for the electromagnet shield effect of test sample exactly provides technical guarantee.
Description of drawings
Fig. 1 is a coaxial axis method proving installation structural representation;
Fig. 2 is a coaxial axis method test philosophy equivalent circuit diagram;
Fig. 3 is the inner laminated structure synoptic diagram that is provided with electro-magnetic screen layer;
Fig. 4 is for testing the equivalent circuit diagram of scale board shield effectiveness shown in Figure 3 by existing mode;
Fig. 5 is for to test the resulting shield effectiveness test curve of scale board by existing mode;
Fig. 6 is the structural representation of used sample in the method for testing of the present invention;
Fig. 7 is a sample cut-open view among Fig. 6;
Fig. 8 is the resulting shield effectiveness test curves of different method of testing test scale boards.
Embodiment
When implementing method of testing of the present invention, at first, make the sample that has test usefulness center pit by the mode identical with existing coaxial cable method of testing; Then, shown in Fig. 6,7, electrically-conducting paint is coated on the sample outer circumference surface and the center pit hole wall on, and utilizing electrically-conducting paint respectively to apply a ring-type conductive coating in sample both side surface edge, the ring-type conductive coating is electrically connected with the screen layer of sample inside by the electrically-conducting paint of the coating on the sample outer circumference surface; At last, utilize existing coaxial cable proving installation shown in Figure 1 that the sample shield effectiveness is tested.
Since on the sample with proving installation on outer conductor and the conductive pole position that contacts be coated with electrically-conducting paint, and ring-type conductive coating wherein and the conductive coating on the center pit hole wall respectively with scale board in electro-magnetic screen layer radially in outer ledge be electrically connected, therefore, be installed in electro-magnetic screen layer in the sample on the proving installation realized with proving installation in outer conductor and the good electrical of inner wire be connected, overcome the problem that the test result that causes because of contact resistance is excessive that in the past existed can not truly reflect actual conditions.
Utilizing the present invention that inside is provided with the scale board electromagnet shield effect curve that is obtained after the electro-magnetic screen layer scale board is tested is documented among Fig. 8.
Put down in writing the electromagnet shield effect test curve of four kinds of samples among Fig. 8, wherein sample 1 is provided with the electromagnet shield effect test curve of the scale board of electro-magnetic screen layer for the inside that utilizes conventional method to record, sample 4 is not for having the scale board of electro-magnetic screen layer to test the resulting electromagnet shield effect test curve in back with conventional method to inside, sample 2 is tested the resulting scale board electromagnet shield effect test curve in back for utilizing the inventive method to the scale board that inside is provided with electro-magnetic screen layer, and sample 3 is tested the resulting electromagnet shield effect test curve in back for utilizing conventional method to simple electromagnetic screen metal level.
As can be seen from Figure 8, in sample 4 scale boards because of electro-magnetic screen layer is not set, thereby do not have an effect of any electromagnetic screen, and the usefulness curve of the test curve of sample 2 and simple electro-magnetic screen layer is identical substantially, therefore, proof is utilized method of testing of the present invention to carry out the scale board shield effectiveness and is tested, can truly reflect the shielding properties of scale board.Along with the release of method of testing of the present invention, will change for a long time the situation that can't carry out Validity Test to the electromagnet shield effect that inside is provided with the material of electro-magnetic screen layer, for providing theoretical, the practical application of these materials supports.
In the foregoing description, though only the scale board that is provided with electro-magnetic screen layer with inside is as tested object, in fact the present invention is not limited to the test to scale board, utilizes the inventive method to test the scale board of various materials.
Claims (1)
1. inner be provided with the coaxial method of testing of scale board shield effectiveness that electro-magnetic screen layer and material upper and lower surface all insulate, this method of testing is specially: at first, make sample by the mode identical with existing coaxial cable method of testing, this sample has the test center pit; Then, electrically-conducting paint is coated on the sample outer circumference surface and the center pit hole wall on, and utilize electrically-conducting paint respectively to apply two consistent with the internal and external conductor face size of existing coaxial cable proving installation respectively ring-type conductive coatings in the sample both side surface, wherein outside ring-type conductive coating is electrically connected with the screen layer of sample inside by the electrically-conducting paint that applies on the sample outer circumference surface, and inboard ring-type conductive coating is electrically connected with the screen layer of sample inside by the electrically-conducting paint that applies on the sample center pit hole wall; At last, the existing coaxial cable proving installation of utilization is finished the test to the sample shield effectiveness, be installed in the sample electrically-conducting paint by applying on its lip-deep ring-type conductive coating and the center hole wall respectively on the existing coaxial cable proving installation, its inner screen layer is realized and have the coaxial cable proving installation now in outer conductor and the good electrical of inner wire be connected.
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| CN 200710177338 CN101149417B (en) | 2007-11-14 | 2007-11-14 | Screen performance test method for veneer with built-in electromagnetic layer |
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| CN101149417B true CN101149417B (en) | 2010-10-13 |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101526486B (en) * | 2009-04-20 | 2011-05-18 | 河北科技大学 | Anti-electromagnetic radiation textile simulating and testing instrument |
| CN103926426B (en) * | 2013-01-14 | 2017-06-30 | 中国人民解放军军械工程学院 | For the coaxial wire holder of broadband continuous conductor of Materials ' Shielding Effectiveness test |
| CN104237575B (en) * | 2014-10-10 | 2017-03-08 | 天津工业大学 | A kind of coaxial holder of test material electromagnetic property |
| CN105812071A (en) * | 2014-12-30 | 2016-07-27 | 展讯通信（上海）有限公司 | Wireless signal penetration test system, penetration test device therefor and wireless signal penetration test method |
| CN108896828A (en) * | 2018-07-05 | 2018-11-27 | 北京无线电计量测试研究所 | A kind of support structures and concentric tapered TEM cell |
| CN109521458B (en) * | 2018-11-21 | 2023-11-24 | 中国标准化研究院 | Device and method for testing radiation protection performance |
| CN111122987B (en) * | 2019-12-26 | 2020-12-04 | 华北电力大学 | Magnetic field shielding effectiveness prediction method and system |
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| JP2523361B2 (en) * | 1989-02-23 | 1996-08-07 | 三菱電線工業株式会社 | Jig for shielding effect of electromagnetic shield material |
| CN101025428A (en) * | 2006-02-20 | 2007-08-29 | 西安科耐特科技有限责任公司 | Radio frequency coaxial microband connector test sample and its test method |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2523361B2 (en) * | 1989-02-23 | 1996-08-07 | 三菱電線工業株式会社 | Jig for shielding effect of electromagnetic shield material |
| CN101025428A (en) * | 2006-02-20 | 2007-08-29 | 西安科耐特科技有限责任公司 | Radio frequency coaxial microband connector test sample and its test method |
Non-Patent Citations (6)
| Title |
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| JP特许2523361B2 1996.05.31 |
| 刘贤淼.木基电磁屏蔽功能复合材料（叠层型）的工艺与性能.中国林业科学研究院硕士论文.2005,35(3),全文. * |
| 李刚，等.平板型电磁屏蔽材料的同轴测试方法.电讯技术35 3.1995,35(3),全文. |
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| 王素英.平板型复合屏蔽材料屏蔽效能测试技术的研究.安全与电磁兼容 2.1995,35(3),全文. * |
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