CN107843793B - Test frame, shielding effectiveness test system and test method thereof - Google Patents
Test frame, shielding effectiveness test system and test method thereof Download PDFInfo
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- CN107843793B CN107843793B CN201711202538.0A CN201711202538A CN107843793B CN 107843793 B CN107843793 B CN 107843793B CN 201711202538 A CN201711202538 A CN 201711202538A CN 107843793 B CN107843793 B CN 107843793B
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- 238000005259 measurement Methods 0.000 claims abstract description 26
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Abstract
The invention provides a test frame, a shielding effectiveness test system and a test method thereof, wherein the test frame comprises a grounding flat plate, a first supporting plate, a second supporting plate, a shielding pipe, a receiving antenna and a transmitting antenna; the first support plate is fixedly connected to the grounding plate, the second support plate is fixedly connected to the grounding plate, one end of the transmitting antenna is connected to the first coaxial connector, the other end of the transmitting antenna is connected to the third coaxial connector, one end of the receiving antenna is connected to the second coaxial connector, and the other end of the receiving antenna is connected to the fourth coaxial connector; one end of the shielding pipe is connected to the first supporting plate, the other end of the shielding pipe is connected to the second supporting plate, and the receiving antenna is sleeved in the shielding pipe. The embodiment of the invention can effectively measure or evaluate the shielding effectiveness of the shielding tubular object, and has the advantages of simple operation and accurate measurement result.
Description
Technical Field
The invention relates to the technical field of electromagnetic shielding, in particular to a test frame, a shielding effectiveness test system and a test method thereof.
Background
With the development of information technology, more and more information needs to be transmitted through lines, communication lines are denser, crosstalk and information leakage between the communication lines are more serious, and the problem of line shielding is widely focused; at present, a shielding pipe or a soft shielding cloth wrapping method is generally adopted, and the problem of signal leakage or external interference is solved by a shielding isolation technical means so as to improve the shielding efficiency between communication lines.
In the prior art, no suitable measuring method or evaluating method for shielding effectiveness of a soft shielding cloth wrapping or shielding pipe exists; the shielding effectiveness measurement of the soft shielding cloth is usually performed by referring to the state army standard GJB 6190-2008 electromagnetic shielding material shielding effectiveness measurement method, but the standard can only test materials cut into small squares, and the shielding tubular objects have different shapes and sizes, so the standard is not suitable for the shielding effectiveness measurement of the shielding tubular objects, and a proper shielding effectiveness measurement device for the shielding tubular objects is not provided, so that the shielding effectiveness measurement of the shielding tubular objects is difficult to operate, and the accuracy of the measurement result is not high.
Disclosure of Invention
The embodiment of the invention provides a test frame, a shielding effectiveness test system and a test method thereof, which are used for solving the technical problems that the conventional shielding effectiveness measurement method or evaluation method is not suitable for measuring or evaluating the shielding effectiveness of a shielding pipe and a proper measuring device is not available at the same time, so that the shielding effectiveness of a shielding pipe can be effectively measured or evaluated, and the operation is simple and the measurement result is accurate.
In order to solve the technical problems, an embodiment of the present invention provides a test rack, which includes a ground plane, a first support plate, a second support plate, a shielding tube, a receiving antenna, and a transmitting antenna for transmitting electromagnetic waves; the first support plate is fixedly connected to the grounding plate, the second support plate is fixedly connected to the grounding plate, a first coaxial connector and a second coaxial connector are arranged on the first support plate, and a third coaxial connector and a fourth coaxial connector are arranged on the second support plate; one end of the transmitting antenna is connected to the first coaxial connector, the other end of the transmitting antenna is connected to the third coaxial connector, one end of the receiving antenna is connected to the second coaxial connector, and the other end of the receiving antenna is connected to the fourth coaxial connector; one end of the shielding pipe is connected to the first supporting plate, the other end of the shielding pipe is connected to the second supporting plate, and the receiving antenna is sleeved in the shielding pipe.
Preferably, the transmitting antenna is parallel to the receiving antenna, and the axis of the shielding pipe is on the same straight line with the axis of the receiving antenna.
Preferably, shielding pipe clamping pieces are arranged on the first supporting plate and the second supporting plate; the shielding pipe clamping piece comprises a first clamping piece and a second clamping piece, wherein the first clamping piece and the second clamping piece are used for clamping one end part of the shielding pipe, a first open slot is formed in the first clamping piece, a second open slot is formed in the second clamping piece, and the opening of the first open slot is opposite to the opening of the second open slot; the first clamping member and the second clamping member move in opposite directions while clamping the shielding pipe; the first clamp and the second clamp move in opposite directions when the shield tube is released.
Preferably, the first clamping piece and the second clamping piece are respectively provided with a strip-shaped through hole; the first clamping piece of the first supporting plate is connected to the first supporting plate in a vertically movable mode through the strip-shaped through hole, and the second clamping piece of the first supporting plate is connected to the first supporting plate in a vertically movable mode through the strip-shaped through hole; the first clamping piece of the second supporting plate is connected to the second supporting plate in a vertically movable mode through the strip-shaped through hole, and the second clamping piece of the second supporting plate is connected to the second supporting plate in a vertically movable mode through the strip-shaped through hole.
Preferably, the first open groove is V-shaped, and the second open groove is V-shaped; or, the first open slot is arc-shaped, and the second open slot is arc-shaped.
Preferably, the first support plate is provided with a first through hole and a second through hole which penetrate through the first support plate in a front-back manner, and the second support plate is provided with a third through hole and a fourth through hole which penetrate through the first support plate in a front-back manner; one end of the transmitting antenna passes through the first through hole and is connected with the first coaxial connector, and the other end of the transmitting antenna passes through the third through hole and is connected with the third coaxial connector; one end of the receiving antenna penetrates through the second through hole to be connected with the second coaxial connector, and the other end of the receiving antenna penetrates through the fourth through hole to be connected with the fourth coaxial connector.
In order to solve the same technical problems, the invention also provides a shielding effectiveness test system which comprises a vector network analyzer, a first radio frequency cable, a second radio frequency cable and the test frame, wherein the vector network analyzer is provided with a signal output port and a measurement port; one end of the first radio frequency cable is electrically connected with a signal output port of the vector network analyzer, and the other end of the first radio frequency cable is electrically connected with one end of the transmitting antenna through the first coaxial connector; one end of the second radio frequency cable is electrically connected with the measuring port of the vector network analyzer, and the other end of the second radio frequency cable is electrically connected with one end of the receiving antenna through the second coaxial connector.
Preferably, a first isolation attenuator is arranged on the first coaxial connector, and a second isolation attenuator is arranged on the second coaxial connector; one end of the first isolation attenuator is electrically connected with one end of the transmitting antenna, and one end of the second isolation attenuator is electrically connected with one end of the receiving antenna; the other end of the first radio frequency cable is electrically connected with the other end of the first isolation attenuator, and the other end of the second radio frequency cable is electrically connected with the other end of the second isolation attenuator.
Preferably, the third coaxial connector is provided with a first terminal load, and the fourth coaxial connector is provided with a second terminal load; the first terminal load is electrically connected with the other end of the transmitting antenna, and the second terminal load is electrically connected with the other end of the receiving antenna.
In order to solve the same technical problems, the invention also provides a shielding effectiveness test method, which is suitable for the shielding effectiveness test system and comprises the following steps:
S1, when the shielding pipe is not installed, adjusting the vector network analyzer to measure an insertion attenuation mode;
S2, measuring a first insertion attenuation value S 21o through the vector network analyzer;
S3, sleeving the shielding pipe on the receiving antenna, and measuring a second insertion attenuation value S 21s through the vector network analyzer;
s4, calculating shielding effectiveness S of the shielding pipe, wherein S=S 21o-S21s;
s5, adjusting the transmitting frequency of the transmitting antenna, and repeating the steps S1-S4 under at least 10 different transmitting frequencies to obtain shielding effectiveness Si of the shielding tube corresponding to the transmitting frequency;
S6, dividing the transmitting frequency of the transmitting antenna into a plurality of frequency bands to calculate the average value of the shielding effectiveness of the shielding tube in different frequency bands
Compared with the prior art, the embodiment of the invention has the beneficial effects that the embodiment of the invention provides the test rack which comprises a grounding plate, a first support plate, a second support plate, a shielding pipe, a receiving antenna and a transmitting antenna for transmitting electromagnetic waves; the first support plate is fixedly connected to the grounding plate, the second support plate is fixedly connected to the grounding plate, a first coaxial connector and a second coaxial connector are arranged on the first support plate, and a third coaxial connector and a fourth coaxial connector are arranged on the second support plate; one end of the transmitting antenna is connected to the first coaxial connector, the other end of the transmitting antenna is connected to the third coaxial connector, one end of the receiving antenna is connected to the second coaxial connector, and the other end of the receiving antenna is connected to the fourth coaxial connector; one end of the shielding pipe is connected to the first supporting plate, the other end of the shielding pipe is connected to the second supporting plate, and the receiving antenna is sleeved in the shielding pipe. The transmitting antenna and the receiving antenna are placed on the test frame, the transmitting antenna receives signals of a vector signal source to transmit electromagnetic waves, the receiving antenna receives the electromagnetic waves sent by the transmitting antenna, and when the shielding effectiveness of the shielding pipe is measured, the insertion attenuation value of the receiving antenna which is not sleeved in the shielding pipe is measured, so that the insertion loss between the two antennas without the shielding pipe is obtained; the receiving antenna is sleeved in the shielding pipe, so that the insertion attenuation value of the receiving antenna sleeved in the shielding pipe is measured, and the difference between the insertion loss between two antennas when the shielding pipe is not arranged and the insertion loss between two antennas when the shielding pipe is arranged is calculated, so that the shielding effectiveness of the shielding pipe can be simply and effectively obtained; and finally, changing the transmitting frequency of the transmitting antenna, and repeating the measurement operation, so that the average shielding effectiveness of each frequency band of the shielding tubular object is accurately and effectively measured or evaluated. Meanwhile, the embodiment of the invention also provides a shielding effectiveness test system and a test method thereof.
Drawings
FIG. 1 is a schematic diagram of a test rack according to one embodiment of the present invention;
Fig. 2 is a schematic structural view of a first embodiment of a first support plate in an embodiment of the present invention;
Fig. 3 is a front view of a first embodiment of a first support plate in an embodiment of the invention;
fig. 4 is an assembly view of a first embodiment of a first support plate in an embodiment of the invention;
fig. 5 is an assembly view of a second embodiment of the first support plate in an embodiment of the invention;
FIG. 6 is a schematic diagram of a shielding effectiveness testing system according to an embodiment of the present invention;
1, a test frame; 11. a first support plate; 12. a second support plate; 111. a first through hole; 112. a second through hole; 13. a ground plate; 2. a vector network analyzer; 21. a signal output port; 22. a measurement port; 31. a first radio frequency cable; 32. a second radio frequency cable; 4. a shielding tube; 5. a transmitting antenna; 51. a first coaxial connector; 52. a third coaxial connector; 53. a first isolation attenuator; 54. a first terminal load; 6. a receiving antenna; 61. a second coaxial connector; 62. a fourth coaxial connector; 63. a second isolation attenuator; 64. a second terminal load; 7. a shielding tube holder; 71. a first clamping member; 711. a first open slot; 72. a second clamping member; 721. a second open slot; 73. and a strip-shaped through hole.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a preferred embodiment of the present invention provides a test rack 1 including a ground plate 13, a transmitting antenna 5 for transmitting electromagnetic waves, a receiving antenna 6, a shielding pipe 4, a first support plate 11, and a second support plate 12; the first support plate 11 is fixedly connected to the ground plane 13, the second support plate 12 is fixedly connected to the ground plane 13, the first support plate 11 is provided with a first coaxial connector 51 and a second coaxial connector 61, and the second support plate 12 is provided with a third coaxial connector 52 and a fourth coaxial connector 62; one end of the transmitting antenna 5 is connected to the first coaxial connector 51, the other end of the transmitting antenna 5 is connected to the third coaxial connector 52, one end of the receiving antenna 6 is connected to the second coaxial connector 61, and the other end of the receiving antenna 6 is connected to the fourth coaxial connector 62; one end of the shielding pipe 4 is connected to the first supporting plate 11, the other end of the shielding pipe 4 is connected to the second supporting plate 12, and the receiving antenna 6 is sleeved in the shielding pipe 4.
In the embodiment of the present invention, by placing the transmitting antenna 5 and the receiving antenna 6 on the test stand 1, the transmitting antenna 5 receives the signal of the vector signal source to transmit electromagnetic waves, and the receiving antenna 6 receives the electromagnetic waves emitted by the transmitting antenna 5, when the shielding effectiveness of the shielding pipe 4 is measured, the insertion attenuation value of the receiving antenna 6 not sleeved in the shielding pipe 4 is measured first, so as to obtain the insertion loss between the two antennas when the shielding pipe 4 is not provided; the receiving antenna 6 is sleeved in the shielding pipe 4, so that the insertion attenuation value of the receiving antenna 6 sleeved in the shielding pipe 4 is measured, and the difference between the insertion loss between two antennas when the shielding pipe 4 is not arranged and the insertion loss between two antennas when the shielding pipe 4 is arranged is calculated, so that the shielding effectiveness of the shielding pipe 4 can be simply and effectively obtained; finally, the transmitting frequency of the transmitting antenna 5 is changed, and the measuring operation is repeated, so that the average shielding effectiveness of each frequency band of the shielding tubular object is accurately and effectively measured or evaluated.
Referring to fig. 1 and 6, in the embodiment of the present invention, the transmitting antenna 5 is parallel to the receiving antenna 6, and the axis of the shielding pipe 4 and the axis of the receiving antenna 6 are on the same straight line, so that each position of the receiving antenna 6 can receive the electromagnetic wave signal of the transmitting antenna 5, and the shielding effectiveness of the shielding pipe 4 is effectively measured; and meanwhile, the axis of the shielding pipe 4 and the axis of the receiving antenna 6 are on the same straight line, so that the accuracy of a measurement result is improved.
Referring to fig. 2 to 5, in the embodiment of the present invention, the first support plate 11 and the second support plate 12 are provided with a clamping member for the shielding pipe 4; the shielding pipe 4 clamping member comprises a first clamping member 71 and a second clamping member 72 for clamping one end part of the shielding pipe 4, wherein a first open slot 711 is formed in the first clamping member 71, a second open slot 721 is formed in the second clamping member 72, and an opening of the first open slot 711 is opposite to an opening of the second open slot 721; the first clamping piece 71 and the second clamping piece 72 move in opposite directions while clamping the shielding pipe 4; when the shielding pipe 4 is loosened, the first clamping piece 71 and the second clamping piece 72 move along opposite directions, so that two ends of the shielding pipe 4 are effectively clamped, and the shielding pipe 4 with different sizes needs to be replaced for measurement when the sizes of the shielding pipes 4 are different, so that the first clamping piece 71 and the second clamping piece 72 can better clamp according to the sizes of the shielding pipes 4, and further measurement efficiency is improved.
Referring to fig. 4 and 5, in the embodiment of the present invention, it should be noted that the pipe diameter of the shielding pipe 4 ranges from 20 to 300mm, so that the diameter of the first open groove 711 ranges from 20 to 300mm and the diameter of the second open groove 721 ranges from 20 to 300mm in order to accommodate the shielding pipes 4 of different sizes. The first open groove 711 has a V shape, and the second open groove 721 has a V shape; or, the first opening slot 711 is arc-shaped, and the second opening slot 721 is arc-shaped, so as to clamp the shielding pipes 4 with different sizes, so as to measure the shielding effectiveness of the shielding pipes 4 with different sizes.
Referring to fig. 2 and 4, in the embodiment of the present invention, the first clamping member 71 and the second clamping member 72 are provided with a strip-shaped through hole 73; the first clamping member 71 of the first support plate 11 is connected to the first support plate 11 through the bar-shaped through hole 73 in a vertically movable manner, and the second clamping member 72 of the first support plate 11 is connected to the first support plate 11 through the bar-shaped through hole 73 in a vertically movable manner; the first clamping member 71 of the second support plate 12 is connected to the second support plate 12 through the bar-shaped through hole 73 in a vertically movable manner, the second clamping member 72 of the second support plate 12 is connected to the second support plate 12 through the bar-shaped through hole 73 in a vertically movable manner, so that the transmitting antenna 5 and the receiving antenna 6 can be erected between the first support plate 11 and the second support plate 12, and the positions of the first support plate 11 and the second support plate 12 are adjusted, so that the positions of the shielding tube 4 are adjusted through the first clamping member 71 and the second clamping member 72, and the axis of the shielding tube 4 and the axis of the receiving antenna 6 are on the same straight line, so that the accuracy of measurement results is improved.
In the embodiment of the present invention, in order to rationalize the structure, the first support plate 11 is perpendicular to the ground plane 13, and the second support plate 12 is perpendicular to the ground plane 13, so that the first support plate 11 is parallel to the second support plate 12, and the transmitting antenna 5 is parallel to the receiving antenna 6, so that it is ensured that each position of the receiving antenna 6 can receive the electromagnetic wave signal of the transmitting antenna 5 during measurement, and accuracy of measurement results is further improved.
Referring to fig. 1 and 6, in order to rationalize the structure in the embodiment of the present invention, the first support plate 11 is electrically connected to the ground plate 13 and the shielding pipe 4, respectively, and the second support plate 12 is electrically connected to the ground plate 13 and the shielding pipe 4, respectively. The first support plate 11 and the second support plate 12 may be fixed to the ground plate 13 by welding or screw fastening, and the first support plate 11 and the second support plate 12 are both metal plates, and when two ends of the shielding tube 4 are clamped on the first support plate 11 and the second support plate 12 respectively, the shielding tube 4 is electrically connected with the first support plate 11 and the second support plate 12 respectively, so that the shielding tube 4 is well grounded, and reliability of a measurement result is further ensured.
In the embodiment of the present invention, it should be noted that the first support plate 11 and the second support plate 12 are both metal plates, one end of the shielding pipe 4 is electrically connected to the first support plate 11, and the other end of the shielding pipe 4 is electrically connected to the second support plate 12, so as to ensure that the shielding pipe 4 is well grounded, thereby ensuring reliability of the measurement result.
Referring to fig. 2 and 3, in the embodiment of the present invention, a first through hole 111 and a second through hole 112 that penetrate through the first support plate 11 in front and back directions are provided, and a third through hole and a fourth through hole that penetrate through the second support plate 12 in front and back directions are provided; one end of the transmitting antenna 5 passes through the first through hole 111 to be connected with the first coaxial connector 51, and the other end of the transmitting antenna 5 passes through the third through hole to be connected with the third coaxial connector 52; one end of the receiving antenna 6 passes through the second through hole 112 and is connected with the second coaxial connector 61, the other end of the receiving antenna 6 passes through the fourth through hole and is connected with the fourth coaxial connector 62, so that the transmitting antenna 5 and the receiving antenna 6 can be erected between the first supporting plate 11 and the second supporting plate 12, the positions of the first supporting plate 11 and the second supporting plate 12 are adjusted, the first supporting plate 11 is parallel to the second supporting plate 12, and therefore the parallelism of the transmitting antenna 5 and the receiving antenna 6 is achieved, and each position of the receiving antenna 6 can be subjected to electromagnetic wave signals of the transmitting antenna 5 during measurement, and the accuracy of measurement results is improved. Meanwhile, at the time of measurement, the first through hole 111, the second through hole 112, the third through hole and the fourth through hole facilitate the installation of the transmitting antenna 5 and the receiving antenna 6, and facilitate the insertion of the first coaxial connector 5, the second coaxial connector 61, the third coaxial connector 52 and the fourth coaxial connector 62 on the first support plate 11 and the second support plate 12.
Referring to fig. 6, in order to solve the same technical problem, the invention further provides a shielding effectiveness test system, which comprises a vector network analyzer 2, a first radio frequency cable 31, a second radio frequency cable 32 and the test rack 1, wherein the vector network analyzer 2 is provided with a signal output port 21 and a measurement port 22; one end of the first radio frequency cable 31 is electrically connected with the signal output port 21 of the vector network analyzer 2, and the other end of the first radio frequency cable 31 is electrically connected with one end of the transmitting antenna 5 through the first coaxial connector 51; one end of the second radio frequency cable 32 is electrically connected to the measurement port 22 of the vector network analyzer 2, and the other end of the second radio frequency cable 32 is electrically connected to one end of the receiving antenna 6 through the second coaxial connector 61.
In the embodiment of the present invention, by placing the transmitting antenna 5 and the receiving antenna 6 on the test stand 1, the transmitting antenna 5 receives the signal of the vector signal source to transmit electromagnetic waves, and the receiving antenna 6 receives the electromagnetic waves emitted by the transmitting antenna 5, when the shielding effectiveness of the shielding pipe 4 is measured, the insertion attenuation value of the receiving antenna 6 not sleeved in the shielding pipe 4 is measured first, so as to obtain the insertion loss between the two antennas when the shielding pipe 4 is not provided; further, the difference between the insertion loss between the two antennas without the shield pipe 4 and the insertion loss between the two antennas with the shield pipe 4 is calculated, so that the shielding performance of the shield pipe 4 can be simply and effectively obtained; finally, the transmitting frequency of the transmitting antenna 5 is changed, and the measuring operation is repeated, so that the average shielding effectiveness of each frequency band of the shielding tubular object is accurately and effectively measured or evaluated.
Referring to fig. 1, in the embodiment of the present invention, a first isolation attenuator 53 is provided on the first coaxial connector 51, and a second isolation attenuator 63 is provided on the second coaxial connector 61; one end of the first isolation attenuator 53 is electrically connected to one end of the transmitting antenna 5, and one end of the second isolation attenuator 63 is electrically connected to one end of the receiving antenna 6; the other end of the first rf cable 31 is electrically connected to the other end of the first isolation attenuator 53, and the other end of the second rf cable 32 is electrically connected to the other end of the second isolation attenuator 63, so as to reduce emission loss, and further improve the accuracy of measuring insertion attenuation by the vector network analyzer 2.
In the embodiment of the present invention, it should be noted that the first isolation attenuator 53 and the second isolation attenuator 63 are 10dB isolation attenuators, and may be isolation attenuators with other specifications, which are not described herein.
Referring to fig. 1 and 6, in an embodiment of the present invention, a first termination 54 is provided on the third coaxial connector 52 and a second termination 64 is provided on the fourth coaxial connector 62; the first terminating load 54 is electrically connected to the other end of the transmitting antenna 5, and the second terminating load 64 is electrically connected to the other end of the receiving antenna 6, so as to reduce the transmission loss and further improve the accuracy of measuring the shielding effectiveness of the shielding tube.
In the embodiment of the present invention, it should be noted that the vector network analyzer 2 is a vector network analyzer 2. The first end load 54 and the second end load 64 are both 50Ω end loads to match the vector network analyzer 2.
In order to solve the same technical problems, the invention also provides a shielding effectiveness test method, which is suitable for the shielding effectiveness test system and comprises the following steps:
S1, when the shielding pipe 4 is not installed, adjusting the vector network analyzer 2 to measure an insertion attenuation mode;
S2, measuring a first insertion attenuation value S 21o through the vector network analyzer 2;
S3, sleeving the shielding tube 4 on the receiving antenna 6, and measuring a second insertion attenuation value S 21s through the vector network analyzer 2;
S4, calculating shielding effectiveness S of the shielding pipe 4, wherein S=S 21o-S21s;
S5, adjusting the transmitting frequency of the transmitting antenna 5, and repeating the steps S1-S4 under at least 10 different transmitting frequencies to obtain the shielding effectiveness Si of the shielding tube corresponding to the transmitting frequency;
s6, dividing the transmitting frequency of the transmitting antenna 5 into a plurality of frequency bands to calculate the average value of the shielding effectiveness of the shielding pipe 4 in different frequency bands
S, the shielding effectiveness of the shielding pipe 4 is expressed in dB;
S 21o, when the shielding pipe 4 is not used, the first insertion attenuation value S 21o measured by the vector network analyzer 2 is expressed in dB;
S 21s, when the shielding pipe 4 is arranged, a second insertion attenuation value S 21s measured by the vector network analyzer 2 is expressed in dB;
The diameter of the shielding pipe 4 is 20-300 mm;
the transmitting frequency range of the transmitting antenna 5 is: 1 MHz-8 GHz.
In the embodiment of the present invention, it should be noted that, since the shielding effectiveness of the shielding pipe 4 has different shielding effectiveness at different frequencies, it is necessary to select a plurality of frequency points within the entire working frequency range for measurement, and the number of frequency points should not be less than 10 points;
the shielding effectiveness of the shielding pipe 4 should be evaluated as an average value in a frequency band.
According to the embodiment of the invention, the full frequency band can be divided into a plurality of small sections according to specific working requirements, so that the average shielding effectiveness of the small frequency band can be obtained. If the operating frequency band is narrow, a part of the small frequency band can be separated. For example, the operating frequency range is (10 to 3000) MHz, and can be divided into (10 to 100) MHz, (100 to 1000) MHz, and (1000 to 3000) MHz.
Calculating the shielding effectiveness average by
In the method, in the process of the invention,The shielding effectiveness of the shielding pipe 4 in a specified frequency band is average in dB;
s i, the shielding effectiveness of the shielding pipe 4 at the ith frequency point is expressed in dB;
n, the total number of frequency points of the frequency band is measured.
Therefore, the shielding effectiveness test system can accurately and effectively measure or evaluate the shielding effectiveness of the shielding pipe, and can measure the shielding effectiveness of the shielding pipes 4 of different sizes to perform the measurement or evaluation of the shielding effectiveness of the shielding pipes 4.
In summary, the embodiment of the invention provides a test rack 1, which comprises a grounding plate 13, a first supporting plate 11, a second supporting plate 12, a shielding tube 4, a receiving antenna 5 and a transmitting antenna 6 for transmitting electromagnetic waves; the first support plate 11 is fixedly connected to the ground plane 13, the second support plate 12 is fixedly connected to the ground plane 13, the first support plate 11 is provided with a first coaxial connector 51 and a second coaxial connector 61, and the second support plate 12 is provided with a third coaxial connector 52 and a fourth coaxial connector 62; one end of the transmitting antenna 5 is connected to the first coaxial connector 51, the other end of the transmitting antenna 5 is connected to the third coaxial connector 52, one end of the receiving antenna 6 is connected to the second coaxial connector 61, and the other end of the receiving antenna 6 is connected to the fourth coaxial connector 62; one end of the shielding pipe 4 is connected to the first supporting plate 11, the other end of the shielding pipe 4 is connected to the second supporting plate 12, and the receiving antenna 6 is sleeved in the shielding pipe 4. By placing the transmitting antenna 5 and the receiving antenna 6 on the test rack 1, the transmitting antenna 5 receives the signal transmitted electromagnetic wave of the vector signal source, and the receiving antenna 6 receives the electromagnetic wave emitted by the transmitting antenna 5, when the shielding effectiveness of the shielding pipe 4 is measured, the insertion attenuation value of the receiving antenna 6 which is not sleeved in the shielding pipe 4 is measured, so that the insertion loss between the two antennas when the shielding pipe 4 is not arranged is obtained; the receiving antenna 6 is sleeved in the shielding pipe 4, so that the insertion attenuation value of the receiving antenna 6 sleeved in the shielding pipe 4 is measured, and the difference between the insertion loss between two antennas when the shielding pipe 4 is not arranged and the insertion loss between two antennas when the shielding pipe 4 is arranged is calculated, so that the shielding effectiveness of the shielding pipe 4 can be simply and effectively obtained; finally, the transmitting frequency of the transmitting antenna 5 is changed, and the measuring operation is repeated, so that the average shielding effectiveness of each frequency band of the shielding tubular object is accurately and effectively measured or evaluated.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (6)
1. The test rack is characterized by comprising a grounding flat plate, a first supporting plate, a second supporting plate, a shielding pipe, a receiving antenna and a transmitting antenna for transmitting electromagnetic waves;
The first support plate is fixedly connected to the grounding plate, the second support plate is fixedly connected to the grounding plate, a first coaxial connector and a second coaxial connector are arranged on the first support plate, and a third coaxial connector and a fourth coaxial connector are arranged on the second support plate;
One end of the transmitting antenna is connected to the first coaxial connector, the other end of the transmitting antenna is connected to the third coaxial connector, one end of the receiving antenna is connected to the second coaxial connector, and the other end of the receiving antenna is connected to the fourth coaxial connector;
One end of the shielding pipe is connected to the first supporting plate, the other end of the shielding pipe is connected to the second supporting plate, and the receiving antenna is sleeved in the shielding pipe;
the transmitting antenna is parallel to the receiving antenna, and the axis of the shielding pipe and the axis of the receiving antenna are on the same straight line;
wherein shielding pipe clamping pieces are arranged on the first supporting plate and the second supporting plate; the shielding pipe clamping piece comprises a first clamping piece and a second clamping piece, wherein the first clamping piece and the second clamping piece are used for clamping one end part of the shielding pipe, a first open slot is formed in the first clamping piece, a second open slot is formed in the second clamping piece, and the opening of the first open slot is opposite to the opening of the second open slot; the first clamping member and the second clamping member move in opposite directions while clamping the shielding pipe; the first clamp and the second clamp move in opposite directions when the shielding tube is released;
The first clamping piece and the second clamping piece are respectively provided with a strip-shaped through hole; the first clamping piece of the first supporting plate is connected to the first supporting plate in a vertically movable mode through the strip-shaped through hole, and the second clamping piece of the first supporting plate is connected to the first supporting plate in a vertically movable mode through the strip-shaped through hole; the first clamping piece of the second supporting plate is connected to the second supporting plate in a vertically movable mode through the strip-shaped through hole, and the second clamping piece of the second supporting plate is connected to the second supporting plate in a vertically movable mode through the strip-shaped through hole;
The first support plate is provided with a first through hole and a second through hole which penetrate through the first support plate in a front-back manner, and the second support plate is provided with a third through hole and a fourth through hole which penetrate through the first support plate in a front-back manner; one end of the transmitting antenna passes through the first through hole and is connected with the first coaxial connector, and the other end of the transmitting antenna passes through the third through hole and is connected with the third coaxial connector; one end of the receiving antenna penetrates through the second through hole to be connected with the second coaxial connector, and the other end of the receiving antenna penetrates through the fourth through hole to be connected with the fourth coaxial connector.
2. The test rack of claim 1, wherein the first open slot is V-shaped and the second open slot is V-shaped; or, the first open slot is arc-shaped, and the second open slot is arc-shaped.
3. A shielding effectiveness test system, which is characterized by comprising a vector network analyzer, a first radio frequency cable, a second radio frequency cable and the test rack according to any one of claims 1-2, wherein the vector network analyzer is provided with a signal output port and a measurement port;
One end of the first radio frequency cable is electrically connected with a signal output port of the vector network analyzer, and the other end of the first radio frequency cable is electrically connected with one end of the transmitting antenna through the first coaxial connector;
One end of the second radio frequency cable is electrically connected with the measuring port of the vector network analyzer, and the other end of the second radio frequency cable is electrically connected with one end of the receiving antenna through the second coaxial connector.
4. The shielding effectiveness test system of claim 3, wherein a first isolation attenuator is provided on the first coaxial connector and a second isolation attenuator is provided on the second coaxial connector;
One end of the first isolation attenuator is electrically connected with one end of the transmitting antenna, and one end of the second isolation attenuator is electrically connected with one end of the receiving antenna;
the other end of the first radio frequency cable is electrically connected with the other end of the first isolation attenuator, and the other end of the second radio frequency cable is electrically connected with the other end of the second isolation attenuator.
5. The shielding effectiveness test system of claim 3 or 4, wherein a first termination is provided on the third coaxial connector and a second termination is provided on the fourth coaxial connector;
The first terminal load is electrically connected with the other end of the transmitting antenna, and the second terminal load is electrically connected with the other end of the receiving antenna.
6. A shielding effectiveness test method, which is suitable for the shielding effectiveness test system according to any one of claims 3 to 5, comprising the steps of:
S1, when the shielding pipe is not installed, adjusting the vector network analyzer to measure an insertion attenuation mode;
S2, measuring a first insertion attenuation value S 21o through the vector network analyzer;
S3, sleeving the shielding pipe on the receiving antenna, and measuring a second insertion attenuation value S 21s through the vector network analyzer;
s4, calculating shielding effectiveness S of the shielding pipe, wherein S=S 21o-S21s;
s5, adjusting the transmitting frequency of the transmitting antenna, and repeating the steps S1-S4 under at least 10 different transmitting frequencies to obtain shielding effectiveness Si of the shielding tube corresponding to the transmitting frequency;
S6, dividing the transmitting frequency of the transmitting antenna into a plurality of frequency bands to calculate the average value of the shielding effectiveness of the shielding tube in different frequency bands 。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711202538.0A CN107843793B (en) | 2017-11-24 | Test frame, shielding effectiveness test system and test method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711202538.0A CN107843793B (en) | 2017-11-24 | Test frame, shielding effectiveness test system and test method thereof |
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| CN107843793B true CN107843793B (en) | 2024-07-05 |
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| CN105116249A (en) * | 2015-08-06 | 2015-12-02 | 西安电子科技大学 | Broadband shielding effectiveness test device of small shielding chassis and method |
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| CN105116249A (en) * | 2015-08-06 | 2015-12-02 | 西安电子科技大学 | Broadband shielding effectiveness test device of small shielding chassis and method |
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