CN201536156U - Electromagnetic shielding efficiency test device of small shielding body and radio-frequency antenna and dot frequency radiation source therein - Google Patents
Electromagnetic shielding efficiency test device of small shielding body and radio-frequency antenna and dot frequency radiation source therein Download PDFInfo
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- CN201536156U CN201536156U CN2009201105043U CN200920110504U CN201536156U CN 201536156 U CN201536156 U CN 201536156U CN 2009201105043 U CN2009201105043 U CN 2009201105043U CN 200920110504 U CN200920110504 U CN 200920110504U CN 201536156 U CN201536156 U CN 201536156U
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Abstract
The utility model provides an electromagnetic shielding efficiency test device of a small shielding body and a radio-frequency antenna and a dot frequency radiation source therein. A plurality of frequency points are selected in the frequency range required to be measured are measured. In the utility model, the dot frequency radiation source is used as a signal source and placed in the small shielding body to be measured; and the signals are transmitted outside the small shielding body through different antennae at different frequencies, then are received by corresponding receiving antennae outside the small shielding body, amplified and output to a frequency spectrograph for measurement, wherein the transmitting antennae are processed to minimum extent and are arranged in the dot frequency radiation source, in particular to transmitting antennae in a magnetic field adopt the brand-new design and a honeycomb type winding method so as to greatly improve the transmitting efficiency. The design of the brand-new coplanar annular antennae with an electric shielding function are applied to receiving antennae in the magnetic field, so that the receiving antennae have the characteristic of hardly influencing the measuring performance after being turned over by 180 degrees. The test device has the advantage of simple and convenient use, lower cost and popularization and application values.
Description
Technical field
The utility model relates to the electromagnetic compatibility test technical field, is meant a kind of testing apparatus and radio-frequency antenna wherein and some frequency radiation source that is used for the test of small shield electromagnet shield effect especially.
Background technology
Along with the extensive use of electronic technology, the electromagnetic interference problem between electromagnetic radiation or the electronic equipment is more and more serious.Information equipment in the other concerning security matters system also needs to take the electromagnetic protection measure to prevent electromagnetic leakage.Various electromagnetic shielding measures and shield have been produced thereupon.Generally speaking, come branch that two kinds of shields are arranged from size: small shield and big shield.Small shield is meant the closed shape that all kinds of soft or hard shielding materials of the length of side between 0.4m and 2m are made.It is a important component part in electromagnetic compatibility (EMC) field tests that small shield is carried out electromagnet shield effect test, and current demand of especially all kinds of small shields being carried out the electromagnet shield effect test in 80Hz ~ 40GHz frequency range is growing.
The method of existing two kinds of test small shield screening effectivenesss: external radiation source method and built-in radiation source method.External radiation source method is by placing signal source in tested shield outside, produce the radiation field of certain frequency scope via transmitting antenna, in tested shield, receive the signal that above-mentioned transmitting antenna produces with receiving transducer again, output to a receiving equipment then, with measurement have, field intensity during unshielded body, field intensity numerical value (unit of field intensity is decibel) to twice measurement compares at last, just can draw the screening effectiveness of tested shield.Built-in radiation source method is that radiation source is positioned in the tested shield, electromagnetic signal in tested shield external application reception antenna receiver radiation source by transmission antennas transmit, output to receiving equipment then, the same intensity difference of measuring the electromagnetic field that receives when shield being arranged and not having shield is to measure the shielding properties of shield.
Above-mentioned existing two kinds of method of measurement all cause many problems to actual operator, and make testing apparatus or system cost very high yet in practice.For example, in external radiation source method, how at 80Hz ~ 40GHz frequency range selective reception probe or transmitting probe, how probe passes in and out tested shield, and the screening effectiveness of import and export how, and how a whole set of test macro is built etc.; For built-in radiation source method, also can produce the problem how to make up radiation source, how to dispel the heat in the small shield space of length of side 0.4m.Usually these problems not only make the tester be difficult to select satisfied testing apparatus, and also relatively more difficult concerning the manufacturer of small shield.Therefore how to provide that a kind of conformance with standard requires, easy and simple to handle, practical and reliable small shield electromagnet shield effect test macro and method just seem very important, very urgent.
Summary of the invention
The purpose of this utility model provides a kind of miniaturization, small shield electromagnetic shielding performance testing device easy to operate, that be suitable for practicality reaches wherein radio-frequency antenna and some frequency radiation source.
Aspect first, the utility model testing apparatus comprises a kind of radio-frequency antenna, and it is made up of first inductance, second inductance, at least one electric capacity and a resistance.Described electric capacity has the first terminal.When described radio-frequency antenna is used to launch the signal with certain frequency, the first terminal of described electric capacity connects the described device with signal of certain frequency of generation, when described radio-frequency antenna is used for received signal, the signal that the first terminal output of described electric capacity receives, the other end of described electric capacity connects an end of described first inductance, the other end ground connection of described first inductance.A terminal ground connection of described second inductance, another terminal is connected with described resistance.One end of described resistance connects described second inductance, other end ground connection.
Above-mentioned radio-frequency antenna is a loop aerial, and behind the one point earth on this loop aerial coil, the two parts that separated by earth point are respectively described first inductance and second inductance.In addition, can be at the outer setting change over switch of the radio-frequency antenna device of described loop aerial, to regulate the signal that described first inductance and described second inductance receive different frequency.
Second aspect of the present utility model provides a kind of some frequency radiation source in electromagnetic screen.When above-mentioned radio-frequency antenna was used to launch the signal with certain frequency, it was included in this frequency radiation source.This frequency radiation source comprises frequency source, is used to produce the signal with certain frequency; Point is power amplifier frequently, connects the output of described frequency source, and described signal with certain frequency is carried out power amplification; Radio-frequency antenna receives describedly by the signal after frequently power amplifier amplifies, and this signal is launched.
More specifically, in aforesaid some frequency radiation source, frequency source wherein comprises that a crystal oscillation device connects some phase locked source frequently, by the described signal with certain frequency of this some phase locked source output frequently.
In above-mentioned some frequency radiation source, can select described crystal oscillation device, some frequency phase locked source, some frequency power amplifier are connected to a power supply by three switches respectively.
In aforesaid some frequency radiation source, described crystal oscillation device, some phase locked source, some frequency power amplifier, power supply and radio-frequency antenna frequently for example are integrated in the box of an insulation.
In aforesaid some frequency radiation source, described three switches are installed in the outer wall of above-mentioned box.
In addition, the outer wall at above-mentioned box indicates the perpendicular polarization of the described radio-frequency antenna of expression and the sign of horizontal polarization.
The 3rd aspect of the utility model provides a kind of device of test panel shielding body electromagnetic shielding performance, comprises aforesaid some frequency radiation source, and comprises the radio frequency reception antenna, is used for the signal that the received RF antenna sends, and exports to preamplifier and amplify.Preamplifier is used for signal to radio frequency reception antenna output and amplifies and output to frequency spectrograph and measure.
Fourth aspect of the present utility model provides a kind of shield electromagnet shield effect tests test method, is used to test the screening effectiveness of small shield in the certain frequency scope.Wherein the radio-frequency antenna of point in the frequency radiation source coplane that keeps at a certain distance away is placed the described radio frequency reception antenna identical with its polarised direction in tested shield.This method of measurement may further comprise the steps: select the some spots frequency to measure in the said frequencies scope, wherein, for each dot frequency, further comprise the inside center position of the some frequency radiation source that produces above-mentioned dot frequency being put into tested shield; Energized makes the preheating of crystal oscillation device; With phase locked source in the frequency radiation source and some power amplifier power supply frequently; Field intensity A and field intensity B when on frequency spectrograph, reading in tested shield and not having tested shield; Relatively field intensity A and field intensity B draw the screening effectiveness of shield.
In above-mentioned method of testing, also comprise the polarised direction that changes radio-frequency antenna, and the polarised direction of corresponding adjusting radio frequency reception antenna, above-mentioned steps repeated.
One of characteristics of the present utility model are to have adopted 80Hz to 40GHz, change the full frequency band continuous measurement into selectable point-frequency measurement.
Two of characteristics of the present utility model are the transmitting antenna of arbitrary frequency in the full frequency band to be carried out the design of miniaturization.
Three of characteristics of the present utility model are that the radio-frequency antenna that is used to launch places in the frequency radiation source.
Four of characteristics of the present utility model be with the transmitter antenna gain (dBi) after the miniaturization Design, receiving antenna gain, point frequently loss, the different frequency range frequency spectrograph of power output, the different frequency range radio frequency cable in source measurement sensitivity and the requirement of emission source frequency stability etc. carried out the system integration, engineering survey thought is run through whole screening effectiveness testing apparatus and method of measurement design process.
Description of drawings
Fig. 1 is the structured flowchart of the utility model small shield electromagnetic shielding performance testing device.
Fig. 2 is that the utility model smaller screen covers the electromagnetic shielding performance testing device structured flowchart, has specifically described some frequency radiation source wherein.
Fig. 3 the utility model smaller screen covers the electromagnetic shielding performance testing device structured flowchart, has specifically described the radio-frequency antenna that is used to transmit and receive in the some frequency radiation source.
Fig. 4 is a flow chart of describing the utility model small shield electromagnet shield effect method of testing.
Embodiment
The utility model provides a kind of cost lower, easy to use, small shield electromagnetism performance testing device that reliability is high and radio-frequency antenna wherein and some frequency radiation source.
At first as shown in Figure 1, it is the device block diagram of small shield electromagnet shield effect test of the present utility model.Whole testing device comprises the some frequency radiation source 30 that is placed in the tested small shield 20 and the radio-frequency antenna outside tested small shield 40, preamplifier 50 and the frequency spectrograph 60 that is used to receive.Whole electromagnetic shielding performance testing device is set in the shielded enclosure 10.The effect of shielded enclosure 10 is to make whole testing device to avoid other electromagnetic interference.
Fig. 2 further launches to have described of the present utility model some frequency radiation source 30 on the basis of Fig. 1.As can be seen from Figure 2, some frequency radiation source 30 comprises a reference frequency source 31, some frequency phase locked source 32, some frequency power amplifier 33 and the radio-frequency antenna 34 that is used to launch.
The utility model is when the screening effectiveness of the small shield of measuring 80Hz ~ 40GHz frequency range, use the high and inefficient problem in broadband signal source and corresponding wideband power amplifier and wide frequency antenna cost in order to overcome prior art, this frequency range is decomposed into a plurality of frequencies measures respectively.For example can sample and select 90Hz, 90KHz, 180KHz, 2MHz, 16MHz, 102MHz, 460MHz, 940MHz, 3.3GHz, 6.2GHz, 11GHz, 18.2GHz, 25GHz, 34GHz, 40GHz equifrequent point.
Be that example explanation the utility model testing apparatus is a screening effectiveness how to test small shield with the 90Hz Frequency point below.With reference to shown in Figure 2, reference frequency source 31, it for example is the crystal oscillation device of a 20MHz constant temperature, be used for being connected to produce more stable 90Hz frequency with some frequency phase locked source 32, the signal with the about 10mV of certain frequency that will produce then outputs to a frequency power amplifier 33 and carries out power amplification, for example, be amplified to 7 ~ 10V, the signal ratio that makes radio-frequency antenna 40 receive is easier to identification.Signal after the amplification is via radio-frequency antenna 34 emissions.
The utility model uses a kind of new loop transmit antenna at each frequency of test 80Hz to 30MHz especially.Because generally the employed toroidal magnetic field of prior art antenna emission effciency is very low, the power output that need strengthen signal source just can reach the requirement of testing standard.In addition, when using loop aerial, if any Rotate 180 of reception antenna °, measured value has the above variation of about 6dB.In order to solve these above-mentioned problems, the utility model is used the radio-frequency antenna of circuit structure as shown in Figure 3, make the measure error after 180 ° of the reception antenna upsets be reduced to 1dB, and because the radio-frequency antenna that is used to launch adopts the honeycomb fashion winding, volume reduce greatly.Satisfy the volume requirement of small shield.
As shown in Figure 3, the radio-frequency antenna 34 that is used to launch comprises capacitor C 1, inductance L 1, L2 and resistance R 1.One end of capacitor C 1 is connected with the some output of power amplifier 33 frequently, and the other end connects a terminal of inductance L 1.The another one terminal ground connection of L1.Also be connected with an end of inductance L 2 simultaneously at the L1 earth terminal.The other end of inductance L 1 connects resistance R 1, by R1 ground connection.Signal with 90Hz is an example, and L1 is approximately 3.8mH, and L2 is 1.5mH, and C1 is 2.7nF, and R1 is 10M Ω.Above-described " ground connection " is actually with reference to zero potential.Inductance L 1 and L2 in Fig. 3 separately describe, and in the practice, can coil be divided into two parts (L1 and L2) realize by with the one point earth on the loop aerial coil.
The structure that it is the above-mentioned radio-frequency antenna that is used for launching 34 that the utility model antenna also has an advantage can be applied in the radio-frequency antenna 40 that is used to receive.Be used for an end ground connection of radio-frequency antenna 40 resistance R 2 that receive in Fig. 3, the other end is via inductance L 3 ground connection.Also be connected an end of inductance L 4 at an end of L3 ground connection, the other end of inductance L 4 is connected with a terminal of capacitor C 2, and the another terminal of capacitor C 2 is connected to preamplifier 50, the signal that receives is outputed to preamplifier 50 amplify.Last preamplifier 50 outputs to frequency spectrograph 60 with amplifying signal and monitors.The HP8565E that frequency spectrograph for example can select Hewlett-Packard to produce.The R2 of the radio-frequency antenna 40 that is used for receiving equates that with resistance R 1 value of the radio-frequency antenna 34 that is used to launch the inductance value of L3 equates that with L2's the inductance value of L4 equates with the value of L1.
Aforementioned use inductance L 1, L2, L3, L4 resistance R 1, R2 and capacitor C 1, C2 just is used for setting forth principle of the present utility model, and the utility model should not be limited to this.Other use the circuit of the device that is equal to mutually with the utility model inductance, electric capacity and resistance also should be encompassed within the protection range of the present utility model.
In addition, reference frequency source 31, some frequency phase locked source 32, some frequency power amplifier 33 are connected to the D.C. regulated power supply 70 of a 12V respectively by K switch 1, K2 and K3, by these power supply 70 power supplies, as shown in Figure 3.Power supply 70 can be the battery that can be recharged.
In small shield performance testing device of the present utility model, by reference frequency source 31, point frequently phase locked source, point frequently the some frequency radiation source 30 that constitutes of power amplifier 33 and the radio-frequency antenna 34 that is used to launch can be integrated in the nonmetallic little chest.Because loop aerial has level and vertical two polarised directions.When carrying out the screening effectiveness test, radio-frequency antenna 34 that is used to launch and the radio-frequency antenna that is used to receive 40 best coplanes are placed.Corresponding with level and two kinds of polarised directions of Vertical Launch of antenna, measure the polarization sign in the case surface level that is marked with of chest with vertical two kinds.The placement direction that indicates the radio-frequency antenna that selection is used to receive according to this polarization.In addition, above-mentioned K switch 1, K2, K3 independently can be provided with or be integrated in together the outside of little chest, be convenient to operation.
When using toroidal radio frequency antenna 40 received signals of the present utility model, can make radio-frequency antenna 40 can receive the more signal of multifrequency point by the value of regulating L1 and L2.In order to realize above-mentioned adjusting, change over switch can fix up an aerial wire in the outside of toroidal radio frequency antenna 40.According to enlightenment of the present utility model, those skilled in the art can be easy to realize this point.
The method of testing of the utility model small shield performance testing device is described below in conjunction with Fig. 4.
Before using the test of the utility model small shield screening effectiveness testing apparatus, earlier tested small shield 20 is positioned on ground wood table that for example 30 ~ 80cm is high or insulating barrier, and ground connection.Again with a certain distance from tested small shield center and equal-height position set up the antenna 40 that is used to receive.The distance of following band antenna of 30MHz and tested shield for example is 30cm.
Concrete measuring process is described below:
After step 104. preheating finishes, make a frequency phase locked source 32 and some power amplifier 33 energized 70 frequently again.
Step 110: the screening effectiveness of tested small shield is A-B=C.
Step 112. changes the polarised direction of the radio-frequency antenna be used to launch, and the polarised direction of the corresponding adjustment radio-frequency antenna that is used to receive, repeating step 104 ~ 110.
When a plurality of frequencies are measured,, can obtain the electromagnet shield effect of small shield in 80Hz ~ 40GHz frequency range, find possible design defect and improvement direction, or do not reach designing requirement repeating above-mentioned steps at each Frequency point.
When measuring field intensity, the magnetic field intensity of each frequency was poor when the utility model had or not shield at the frequency range build-in test of 80Hz to 30MHz, frequency range build-in test electric field at 30MHz to 950MHz is poor, and is poor in the field intensity of the frequency range build-in test microwave of 950MHz to 40GHz.
If the step of back depends on signal that preceding step produces, result etc. in the above-described step, then before and after order should not put upside down, other steps can change.Those skilled in the art's these variations that instruction is made according to the utility model also should be included within the protection range of the present utility model.
Though be to set forth with the 80Hz ~ 30MHz frequency range example in 80Hz ~ 40GHz, principle of the present utility model is not limited thereto herein.In other frequency ranges, also be suitable for.
The utlity model has following advantage and effect:
1. provide a kind of coincidence measurement standard-required also to satisfy small shield electromagnetic shielding performance testing device and the measuring method of engineering survey needs.
2. testing arrangement all domesticizes, and screen effect is measured the baseline requirement that is above standard, and easy and simple to handle, test result is accurate, has very strong practicality and generalization.
3. measuring method is scientific and reasonable, and it is flexible, portable that measuring frequency is selected, for the manufacturer of small shield provide a cover at a low price, suitable, effective, complete measurement frequency range and research and development instrument.
4. solved that GB, national military standard are measured about the following magnetic field of the engineering survey demand, particularly 30MHz of the test of small shield electromagnet shield effect screen effect and the above microwave of 18GHz shields and imitates measurement.
5. the magnetic field reception antenna has adopted with the brand-new design of the coplanar ring Shape antenna of electric shield so that it has upset 180. After substantially do not affect the characteristics of measurement performance.
Claims (10)
1. radio-frequency antenna, it is characterized in that this radio-frequency antenna comprise first inductance (L1, L4), second inductance (L2, L3), at least one electric capacity (C1, C2) and resistance (R1, R2),
Described electric capacity (C1, C2) has the first terminal, when described radio-frequency antenna (34) is used to launch the signal with certain frequency, the first terminal of described electric capacity (C1) connects the described device with signal of certain frequency of generation, when described radio-frequency antenna (40) when being used for received signal, the signal that the first terminal output of described electric capacity (C2) receives
Described electric capacity (C1, other end C2) connect described first inductance (L1, end L4), described first inductance (L1, other end ground connection L4),
Described second inductance (L2, terminal ground connection L3), another terminal and described resistance (R1 R2) connects,
Described resistance (R1, end R2) connect described second inductance (L2, L3), other end ground connection.
2. according to the radio-frequency antenna of claim 1, it is characterized in that it is a loop aerial, behind the one point earth on this loop aerial coil, the two parts that separate by earth point be respectively described first inductance (L1, L4) and second inductance (L2, L3).
3. according to the radio-frequency antenna of claim 2, it is characterized in that the described radio-frequency antenna of loop aerial (40) the outer setting change over switch that is, with regulate described first inductance (L1, L4) and described second inductance (L2 L3) receives the signal of different frequency.
4. a some frequency radiation source of using radio-frequency antenna in the claim 1 is characterized in that it comprises frequency source (31,32), produces the signal with certain frequency,
Point is power amplifier (33) frequently, connects the output of described frequency source (31,32), and described signal with certain frequency is carried out power amplification,
Radio-frequency antenna (34) receives describedly by the signal after frequently power amplifier (33) amplifies, and this signal is launched.
5. a frequency radiation source according to claim 4 is characterized in that frequency source (31,32) wherein comprises that a crystal oscillation device (31) connects some phase locked source (32) frequently, by the described signal with certain frequency of this some phase locked source output frequently.
6. according to the some frequency radiation source of claim 5, it is characterized in that phase locked source (32), some frequency power amplifier (33) are connected to a power supply (70) by K switch 1, K2, K3 respectively frequently for wherein said crystal oscillation device (31), point.
7. a frequency radiation source according to claim 6, phase locked source (32), some frequency power amplifier (33), power supply (70) and radio-frequency antenna (34) are integrated in the box of an insulation frequently to it is characterized in that wherein said crystal oscillation device (31), point.
8. a frequency radiation source according to claim 7 is characterized in that wherein said K switch 1, K2 and K3 are installed in the outer wall of above-mentioned box.
9. the device of a test panel shielding body electromagnetic shielding performance is characterized in that the some frequency radiation source that it comprises any claim of claim 4 to 8, and comprises
Radio-frequency antenna (40) is used for the signal that received RF antenna (34) sends, and exports to preamplifier (50) and amplify,
Preamplifier (50) amplifies and outputs to frequency spectrograph (60) the signal of radio-frequency antenna (40) output and measures.
10. according to the device of the test panel shielding body electromagnetic shielding performance of claim 9, it is characterized in that described radio-frequency antenna (34) and radio-frequency antenna (40) coplane place.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201105043U CN201536156U (en) | 2009-07-30 | 2009-07-30 | Electromagnetic shielding efficiency test device of small shielding body and radio-frequency antenna and dot frequency radiation source therein |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201105043U CN201536156U (en) | 2009-07-30 | 2009-07-30 | Electromagnetic shielding efficiency test device of small shielding body and radio-frequency antenna and dot frequency radiation source therein |
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| CN201536156U true CN201536156U (en) | 2010-07-28 |
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| CN2009201105043U Expired - Lifetime CN201536156U (en) | 2009-07-30 | 2009-07-30 | Electromagnetic shielding efficiency test device of small shielding body and radio-frequency antenna and dot frequency radiation source therein |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101662078B (en) * | 2009-07-30 | 2012-08-29 | 北京大泽科技有限公司 | Small shielding body electromagnetic shielding performance testing device, system and method therefor |
| CN104881624A (en) * | 2014-02-27 | 2015-09-02 | 中兴通讯股份有限公司 | Radio frequency identification RFID apparatus, method and optical distribution network ODN equipment |
| CN112763818A (en) * | 2020-12-18 | 2021-05-07 | 北京无线电计量测试研究所 | Device and method for measuring broadband shielding effectiveness of small shield |
-
2009
- 2009-07-30 CN CN2009201105043U patent/CN201536156U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101662078B (en) * | 2009-07-30 | 2012-08-29 | 北京大泽科技有限公司 | Small shielding body electromagnetic shielding performance testing device, system and method therefor |
| CN104881624A (en) * | 2014-02-27 | 2015-09-02 | 中兴通讯股份有限公司 | Radio frequency identification RFID apparatus, method and optical distribution network ODN equipment |
| CN112763818A (en) * | 2020-12-18 | 2021-05-07 | 北京无线电计量测试研究所 | Device and method for measuring broadband shielding effectiveness of small shield |
| CN112763818B (en) * | 2020-12-18 | 2023-10-13 | 北京无线电计量测试研究所 | Device and method for measuring broadband shielding effectiveness of small shielding body |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100728 Effective date of abandoning: 20090730 |