CN101005754A - Device for screening electromagnetic wave interference - Google Patents
Device for screening electromagnetic wave interference Download PDFInfo
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- CN101005754A CN101005754A CN 200610000889 CN200610000889A CN101005754A CN 101005754 A CN101005754 A CN 101005754A CN 200610000889 CN200610000889 CN 200610000889 CN 200610000889 A CN200610000889 A CN 200610000889A CN 101005754 A CN101005754 A CN 101005754A
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- electromagnetic wave
- shielding electromagnetic
- ripple layer
- wave interference
- circuit
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Abstract
The method is used for shielding the high frequency electromagnetic wave interference generated by the electron device with high frequency signal circuit or PCB traces. It comprises: adding a wave absorbing layer into inner side of the metal shield mask; the wave absorbing layer locates within the distance of the 0-1/10 wave length to the just upside of the circuit with the problem; its size can't be less than two times of circuit with problem and can totally cover the circuit with problem; there is no metal object between the wave absorbing layer and the circuit with problem.
Description
Technical field
The present invention relates to the device that a kind of shielding electromagnetic wave is disturbed, especially a kind ofly can effectively shield device with high-frequency signal circuit or PCB (Printed Circuit Board, printed wiring board) cabling equipment high band Electromagnetic Interference.
Background technology
Along with development of technology, frequency band, the frequency of electronic equipment are more and more higher, the cabling that hundreds of megahertz even last G hertz signal frequency have all been arranged on a lot of circuit boards, and the external radiation of these signals of telecommunication is relevant with the harmonic wave of this signal with the frequency of accepting external disturbance, frequency is high more, the radiation problem of high band also can be many more, as Electromagnetic Interference, electromagnetic wave information are divulged a secret and electromagnetic environment is polluted harm etc., it has become one more and more seriously and more and more by the problem that people paid close attention to, and the problem that high frequency radiation brings is particularly serious.
Therefore telecom operators are for guaranteeing its product availability, fail safe, reliability etc., the product that equipment manufacturers are provided has proposed the requirement of a series of function, performance and environmental suitability aspect, need pass through the every test of NEBS (Network Equipment-Building System, network equipment system framework) such as telecommunication apparatus is the basic demand that enters American mainstream telecom operators.Compare with the common CE of European Union authentication, though some test events have a lot of difference on degree and scope.But wherein RS (Radiated Sensitivity, radiated susceptibility) and RE (RadiatedEmission, radiated emission) show that (concern of 1G～10GGHz), this is very targeted more and more higher today in the electronic circuit frequency to HFS.
Fig. 1 is the radiated emission electromagnetic wave electric field strength spectrogram that 1.25GHz signal microstrip line produces, from this figure pin-point reading as can be known, all having surpassed the restraining line (annotate: method of testing is referring to GR-1089-CORE in the NEBS standard family) of 60dBuV/m on 3.75GHz and 5.00GHz frequency, is respectively 3 times and 4 subharmonic of the 1.25GHz signal of telecommunication.
Prior art suppresses the method that radiated emission adopts metallic shield usually, existing as shown in Figure 2 shield technology metallic shield commonly used.It is generally pentahedral cuboid can, for heat radiation is considered also can beat array hole on box body, cover on the circuit printing plate that needs shielding, there are some fixing threaded holes etc. and printed circuit board stationary device in the box body edge, after shielding box and printed circuit board are fixing, be connected with the ground circuit network in the printed circuit board, form the metal hexahedron space of a sealing jointly.
By classical shield effectiveness theory as can be known, the shield effectiveness that electronic equipment requires is generally and is not less than 20dB, and will reach the 20dB shield effectiveness time, metallic shield perforate minimum dimension is 1/20 of a wavelength.The 10GHz electromagnetic wavelength is 30cm, reach certain shield effectiveness, and the bore size of shield maximum can not surpass 1.5cm, and this has in the electronic equipment of external interface at majority all is the requirement that is difficult to reach.Under the more situation, screen to shield is imitated higher requirement in addition, adopt the back electromagnetic wave electric field strength spectrogram that produces of simple metal cap shielding as can be seen from 1.25GHz signal microstrip line shown in Figure 3, at 3.5GHz, 3.75GHz, frequency such as 4GHz and 5GHz radiation value has reached 57dBuV/m respectively, 58dBuV/m, 59dBuV/m and 62dBuV/m, wherein 5GHz reaches 62dBuV/m, surpassed limit value, 58dBuV/m and 59dBuV/m can not reach the requirement of 3dB allowance.
Hence one can see that, adopts simple metallic shield be difficult to suppress the generation that electromagenetic wave radiation disturbs, and also is difficult to reach North America NEBS and the CE of the European Union authentication test request to telecommunication apparatus RS and RE.
Summary of the invention
The problem to be solved in the present invention is to provide a kind of device of shielding electromagnetic wave interference, and this device can effectively shield the high band electromagenetic wave radiation with high-frequency signal circuit or PCB cabling equipment and disturb.
For addressing the above problem, the present invention adopts following technical scheme:
The device that a kind of shielding electromagnetic wave is disturbed comprises a metallic shield, it is characterized in that, described metallic shield inboard is provided with one and inhales the ripple layer.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that, the material of described suction ripple layer is selected to satisfy following requirement:
(1) inhale the environmental requirement that the ripple layer material need satisfy: temperature :-60～-375 , relative humidity: 5%～95%, flame-retarding characteristic: UL 94-V1;
(2) inhaling ripple layer material requirement minimal absorption power is the 1W/ square centimeter.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that the preferred silicon rubber base material of described suction ripple layer.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that, the area of described suction ripple layer is more than or equal to the twice of problem circuit area, and complete covering problem circuit.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that described suction ripple layer will be placed in 0～1/10 wavelength distance of problem circuit.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that, described suction ripple layer be located at the inboard problem circuit of metallic shield directly over.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that not having metallic object between described suction ripple layer and the problem circuit.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that described suction ripple layer and metallic shield are close to setting.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that described metallic shield will contact with the earth signal network multiple spot on the circuit board.
The device that above-mentioned shielding electromagnetic wave is disturbed is characterized in that described earth signal is complete one deck.
Compared with prior art, the present invention has the following advantages:
The present invention has overcome simple metallic shield can only can effectively solve the radiated interference problem of the equipment high band with high-frequency signal circuit or PCB cabling at the defective of low frequency radiation, makes external RE of high-frequency apparatus and RS can satisfy requirement for restriction.
Method of operation of the present invention is simple, and is easy to implement, adds absorbing material in the metal cap, do not go out in visual observation, do not increase space requirement, and metal cap also provides perfect physical environment protection for inhaling the ripple layer, reaches high reliability and availability.
Device of the present invention is easy to engineering practice, when electromagnetic interference being researched and analysed when test, can the suction ripple layer material of same-action frequency spectrum carry out by changing not, and be easy to find and solve key issue.When electronic equipment carries out signal frequency after changing in follow-up work, can only change suction ripple layer material and just can reach electromagnetic good control, have higher continuity and autgmentability.
Further specify technical scheme of the present invention below in conjunction with the drawings and specific embodiments.
Description of drawings
Fig. 1 is the radiated emission electromagnetic wave electric field strength spectrogram that 1.25GHz signal microstrip line produces;
Fig. 2 is a prior art veneer metal cap structural representation;
Fig. 3 is the electromagnetic wave electric field strength spectrogram that 1.25GHz signal microstrip line adopts simple metal cap shielding back to produce;
Fig. 4 is an embodiment of the invention structural representation;
Fig. 5 is the electric field strength spectrogram that generates electromagnetic waves after 1.25GHz signal microstrip line adopts the present invention to shield;
Fig. 6 is a kind of suction ripple loss-frequency curve chart of absorbing material.
Embodiment
With reference to figure 4, the device that shielding electromagnetic wave of the present invention is disturbed is at prior art metallic shield 1 inboard one deck suction ripple layer 2 respond well to electro-magnetic wave absorption that increase.This suction ripple layer 2 be positioned at the problem circuit directly over 0～1/10 wavelength distance, its area can not be less than the twice of problem circuit and covering problem circuit fully, does not have metallic object between itself and the problem circuit.During application, inhale the ripple layer and can directly stick on the surface of problem circuit, or adopt other fixed solution to be fixed on the surface of problem circuit, described metallic shield will contact with the earth signal network multiple spot on the circuit board, and described earth signal should have complete one deck.Described problem circuit is meant, is lower than the criteria limit value though the radiation intensity value surpasses the circuit or the radiation intensity of certain criteria limit, and Electromagnetic Interference is too responsive to external world can not bear certain interference and produce the circuit that function, performance reduce.
The material of described suction ripple layer is selected to satisfy following requirement:
(1) need satisfied environmental requirement: temperature :-60～-375 , relative humidity: 5%～95%, flame-retarding characteristic: UL 94-V1;
(2) inhaling ripple layer material requirement minimal absorption power is the 1W/ square centimeter;
(3) to meet European Union's ROHS (ROHS instruction).
In satisfying the material of above-mentioned condition, again with reference to the absorption loss curve of various materials, choose suitable material according to different problem frequencies, the suction ripple loss-frequency curve chart of a kind of absorbing material as shown in Figure 6, expression is to the absorption loss size (ordinate) of different frequent points (abscissa) energy, and unit is dB, from curve as can be seen, the frequency of this kind absorbing material loss maximum is about 12GHz, and loss reaches 17dB.Different absorbing materials, its absorption loss curve has nothing in common with each other, and should select suitable type for use at actual conditions.Such as when circuitry radiation frequency during in the 12GHz left and right sides, select the material of curve shown in Figure 6 to do absorbing material, its radiation-screening interference effect just better, can adopt nano material, plane hexad ferrite, amorphous magnetic fibre, the contour performance absorbing material of membrana granulosa in the application, the preferred material that meets above-mentioned condition is the silicon rubber base material.
The absorbing material principle is that electromagnetic wave energy is converted to surface eddy (electric current) form, convert heat energy to, this kind material all has the maximum power dissipation of an absorption, generally require absorbing material to absorb power consumption and reach 1～2W/ square centimeter, when area is quite big, total power consumption may be just quite high, therefore when emittance is big, heat dispersion be can not ignore, present embodiment is recommended absorbing material and metal case are close to installation, because it is aging that long-term higher temperature can quicken to inhale the ripple layer, bring fracture, problems such as electromagnetism material continuity variation, be close to large-area metal physical efficiency and take away heat rapidly, accelerate heat radiation, can guarantee to inhale ripple layer operate as normal in the lifetime of whole electric equipment.Simultaneously also can select for use the material of the good heat conductivity that satisfies above-mentioned requirements as absorbing material.
Refer again to Fig. 3, can find out, when adopting the metallic shield box body merely, (shield effectiveness of 30M～1GHz) is relatively good for low frequency, if the can design is good, perforate is little, its shield effectiveness may extend into 1G～3GHz., but it is difficult to suppress the high band radiation, and Fig. 5 is the electromagnetic wave electric field strength spectrogram that 1.25GHz signal microstrip line employing the present invention shields the back generation, can find out from this figure, after having used the high frequency absorption material, having changed the electromagnetic wave near field is near the boundary condition of radiating circuit, and causing the far field is the variation significantly of test position situation, wherein among Fig. 3, at 3.5GHz, 3.75GHz frequency radiation values such as 4GHz and 5GHz are all significantly subdued, whole radiation curve meets the requirement of restriction fully.
Though the present invention with preferred embodiment openly as above; right its is not in order to limiting the present invention, anyly is familiar with this operator, without departing from the spirit and scope of the invention; when doing a little change and retouching, the change of doing still belongs within the accompanying Claim protection range of the present invention with retouching.
Claims (10)
1, a kind of device of shielding electromagnetic wave interference comprises a metallic shield, it is characterized in that, described metallic shield inboard is provided with one and inhales the ripple layer.
2, the device of shielding electromagnetic wave interference according to claim 1 is characterized in that, the material of described suction ripple layer is selected to satisfy following requirement:
21) its environmental requirement that need satisfy: temperature :-60～-375 , relative humidity: 5%～95%,
Flame-retarding characteristic: UL 94-V1;
22) its to require minimal absorption power be the 1W/ square centimeter.
3, the device of shielding electromagnetic wave interference according to claim 2 is characterized in that, described suction ripple layer adopts the silicon rubber base material.
4, the device that disturbs according to claim 1,2 or 3 described shielding electromagnetic wave is characterized in that, the area of described suction ripple layer is more than or equal to the twice of problem circuit area, and complete covering problem circuit.
5, the device of shielding electromagnetic wave interference according to claim 4 is characterized in that described suction ripple layer is placed in 0～1/10 wavelength distance of problem circuit.
6, the device that disturbs of shielding electromagnetic wave according to claim 5 is characterized in that, described suction ripple layer be located at the inboard problem circuit of metallic shield directly over.
7, the device of shielding electromagnetic wave interference according to claim 6 is characterized in that not having metallic object between described suction ripple layer and the problem circuit.
8, the device of shielding electromagnetic wave interference according to claim 7 is characterized in that described suction ripple layer and metallic shield are close to setting.
9, the device of shielding electromagnetic wave interference according to claim 1 is characterized in that described metallic shield will contact with the earth signal network multiple spot on the circuit board.
10, the device of shielding electromagnetic wave interference according to claim 9 is characterized in that described earth signal is complete one deck.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610000889 CN101005754A (en) | 2006-01-17 | 2006-01-17 | Device for screening electromagnetic wave interference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610000889 CN101005754A (en) | 2006-01-17 | 2006-01-17 | Device for screening electromagnetic wave interference |
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| CN101005754A true CN101005754A (en) | 2007-07-25 |
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| CN 200610000889 Pending CN101005754A (en) | 2006-01-17 | 2006-01-17 | Device for screening electromagnetic wave interference |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867627A (en) * | 2009-12-22 | 2010-10-20 | 康佳集团股份有限公司 | Shielding cover device of mobile phone baseband |
| CN101742814B (en) * | 2009-12-22 | 2011-08-24 | 华为终端有限公司 | Printed circuit board shielding method and printed circuit board |
| CN102833991A (en) * | 2012-07-19 | 2012-12-19 | 北京京东方光电科技有限公司 | Protective cover of printed circuit board |
| CN105049133A (en) * | 2015-08-06 | 2015-11-11 | 京信通信技术(广州)有限公司 | Smart antenna calibrating device |
| CN106081463A (en) * | 2016-05-30 | 2016-11-09 | 杭州科鼎电子设备有限公司 | A kind of Nicotiana tabacum L. former tune of former receipts, entirely receive tune RFID logistics and go out to put scan code system in storage |
| CN106535605A (en) * | 2016-12-06 | 2017-03-22 | 安科智慧城市技术（中国）有限公司 | Electromagnetic interference shielding device and electric vehicle charger |
| CN106972742A (en) * | 2017-05-27 | 2017-07-21 | 孙宏宇 | A kind of switching power circuit of the extremely low Ripple Noise of High voltage output |
| CN107535079A (en) * | 2015-03-31 | 2018-01-02 | 韩国E3试验研究所株式会社 | Blocking electromagnetic waves device and its manufacture method with electromagnetic wave shielding and absorbent properties |
| CN107994585A (en) * | 2017-12-28 | 2018-05-04 | 国网山东省电力公司滨州供电公司 | A kind of multifunction power control terminal |
| CN110337232A (en) * | 2019-06-25 | 2019-10-15 | 广东以诺通讯有限公司 | A kind of communication device solving GSM CSE |
| CN112219314A (en) * | 2019-04-08 | 2021-01-12 | 郭长来 | Device for reducing antenna interference by radio electromagnetic wave |
| CN112398497A (en) * | 2019-08-16 | 2021-02-23 | 华为技术有限公司 | Radio frequency device and assembling method thereof |
| CN113567471A (en) * | 2021-09-27 | 2021-10-29 | 宜宾盛纬伦科技有限公司 | Device and method for testing high-frequency wave-absorbing performance of wave-absorbing material |
-
2006
- 2006-01-17 CN CN 200610000889 patent/CN101005754A/en active Pending
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101742814B (en) * | 2009-12-22 | 2011-08-24 | 华为终端有限公司 | Printed circuit board shielding method and printed circuit board |
| CN101867627B (en) * | 2009-12-22 | 2015-06-24 | 康佳集团股份有限公司 | Shielding cover device of mobile phone baseband |
| CN101867627A (en) * | 2009-12-22 | 2010-10-20 | 康佳集团股份有限公司 | Shielding cover device of mobile phone baseband |
| CN102833991A (en) * | 2012-07-19 | 2012-12-19 | 北京京东方光电科技有限公司 | Protective cover of printed circuit board |
| WO2014012329A1 (en) * | 2012-07-19 | 2014-01-23 | 北京京东方光电科技有限公司 | Protective cover of printed circuit board |
| CN102833991B (en) * | 2012-07-19 | 2016-06-08 | 北京京东方光电科技有限公司 | A kind of protection lid of printed circuit board |
| CN107535079A (en) * | 2015-03-31 | 2018-01-02 | 韩国E3试验研究所株式会社 | Blocking electromagnetic waves device and its manufacture method with electromagnetic wave shielding and absorbent properties |
| CN105049133A (en) * | 2015-08-06 | 2015-11-11 | 京信通信技术(广州)有限公司 | Smart antenna calibrating device |
| CN106081463A (en) * | 2016-05-30 | 2016-11-09 | 杭州科鼎电子设备有限公司 | A kind of Nicotiana tabacum L. former tune of former receipts, entirely receive tune RFID logistics and go out to put scan code system in storage |
| CN106535605A (en) * | 2016-12-06 | 2017-03-22 | 安科智慧城市技术（中国）有限公司 | Electromagnetic interference shielding device and electric vehicle charger |
| CN106972742A (en) * | 2017-05-27 | 2017-07-21 | 孙宏宇 | A kind of switching power circuit of the extremely low Ripple Noise of High voltage output |
| CN107994585A (en) * | 2017-12-28 | 2018-05-04 | 国网山东省电力公司滨州供电公司 | A kind of multifunction power control terminal |
| CN112219314A (en) * | 2019-04-08 | 2021-01-12 | 郭长来 | Device for reducing antenna interference by radio electromagnetic wave |
| CN110337232A (en) * | 2019-06-25 | 2019-10-15 | 广东以诺通讯有限公司 | A kind of communication device solving GSM CSE |
| CN112398497A (en) * | 2019-08-16 | 2021-02-23 | 华为技术有限公司 | Radio frequency device and assembling method thereof |
| CN113567471A (en) * | 2021-09-27 | 2021-10-29 | 宜宾盛纬伦科技有限公司 | Device and method for testing high-frequency wave-absorbing performance of wave-absorbing material |
| CN113567471B (en) * | 2021-09-27 | 2021-12-21 | 宜宾盛纬伦科技有限公司 | Device and method for testing high-frequency wave-absorbing performance of wave-absorbing material |
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