CN114280381A - On-site calibration method for antenna coefficient of radiation emission test antenna - Google Patents
On-site calibration method for antenna coefficient of radiation emission test antenna Download PDFInfo
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- CN114280381A CN114280381A CN202111523600.2A CN202111523600A CN114280381A CN 114280381 A CN114280381 A CN 114280381A CN 202111523600 A CN202111523600 A CN 202111523600A CN 114280381 A CN114280381 A CN 114280381A
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- 238000012360 testing method Methods 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 22
- 230000005855 radiation Effects 0.000 title abstract description 19
- 239000000523 sample Substances 0.000 claims abstract description 11
- 238000003780 insertion Methods 0.000 claims description 5
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- 238000005259 measurement Methods 0.000 abstract description 4
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Abstract
The invention provides a field calibration method for antenna coefficients of a radiation emission test antenna, which is characterized in that in a calibration test chamber, the antenna coefficients of the antenna to be calibrated are measured and obtained by utilizing the existing test environments including a signal source, a field intensity probe, a field intensity meter and other radiation sensitivity equipment, a frequency spectrograph, a test bed, a test ground and the like. The invention can utilize the existing equipment of the electromagnetic compatibility laboratory to carry out the on-site calibration measurement on the antenna coefficient of the radiation transmitting antenna in the real environment of the laboratory, thereby not only avoiding the problems of antenna damage, long calibration period and the like caused by antenna transportation and the like, but also ensuring the reliability of the antenna coefficient obtained by calibration due to the on-site calibration, and being beneficial to the accuracy of the electromagnetic compatibility radiation transmitting test.
Description
Technical Field
The invention relates to the field of antenna calibration, in particular to a field calibration method for testing an antenna.
Background
The radiation emission test is an important test item in the electromagnetic compatibility test. The content of the radiation emission test is to measure the electromagnetic radiation generated by the device, subsystem or system under test to the external environment through a housing, cable, etc. The principle of radiation emission testing in electromagnetic compatibility testing can be summarized as: the tested device, subsystem or system generates electromagnetic radiation to the outside through a shell, a cable and the like, the electromagnetic radiation excites an induced current on the test antenna, the induced current is output as an induced voltage at the port of the test antenna, and the field intensity value of the electromagnetic radiation can be calculated by utilizing the amplitude of the induced voltage. The key to calculating the field strength of the electromagnetic radiation using the amplitude of the induced voltage at the port of the test antenna in the above-mentioned principles is the mathematical relationship between the two. The term of this mathematical relationship is the antenna coefficient, which is defined as the ratio of the measured electric field strength to the induced voltage at the antenna port under test.
At present, the methods for calibrating and testing the antenna coefficient of a radiation emission test antenna mainly comprise a two-antenna method, a standard antenna method and a three-antenna method.
When the antenna coefficient is measured by adopting the two-antenna method, a pair of antennas which are completely the same as the antenna to be calibrated are used for matching measurement. However, manufacturers and batches of radiation testing antennas of various electromagnetic compatibility laboratories are various, and in practice, it is difficult for a metering mechanism to find the same antenna as an antenna to be tested.
The standard antenna method is to use an antenna with known antenna coefficient as a standard antenna, place the antenna to be calibrated and the standard antenna at the same position respectively to measure the same electric field, compare the signals received by the antenna to be calibrated and the standard antenna, and calculate the antenna coefficient of the antenna to be calibrated according to the antenna coefficient of the standard antenna. This method requires the use of a standard antenna, which is generally only available to professional metering agencies.
The three-antenna method requires two antennas of the same type as the antenna to be calibrated for calibration. The calibration process is as follows: two of the three antennas are used as a combination, the three antennas respectively adopt three different combinations, three times of measurement are carried out, the signal attenuation between the two antennas is measured, and the antenna coefficient of each antenna is solved. This calibration method is the most common, but the operation of this calibration method is also the most complicated.
When the three calibration methods are implemented, whether the calibration is performed in a professional calibration field or a laboratory to be calibrated, additional antenna matching calibration is needed. This involves shipping, packaging, etc. of the antenna, which may damage the antenna during this process, affecting the accuracy of the radiated emissions test for subsequent emc testing. Furthermore, if the antenna to be calibrated is sent to a professional metering mechanism for calibration, the calibrated antenna coefficient may deviate from the actual antenna coefficient in the laboratory environment due to the difference between the metering mechanism site and the laboratory site environment, thereby causing the deviation of the radiation emission test.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a field calibration method for the antenna coefficient of a radiation emission test antenna. Aiming at the defects of the existing method for calibrating the antenna coefficient of the radiation emission test antenna in the electromagnetic compatibility test, the invention measures the antenna coefficient of the antenna to be calibrated in a calibration test chamber by utilizing the existing test environments including a signal source, a field intensity probe, a field intensity meter and other radiation sensitivity equipment, a frequency spectrograph, a test bed, a test ground and the like.
The technical scheme adopted by the invention for solving the technical problem comprises the following specific calibration steps:
step 1: connecting a signal source to a frequency spectrograph through a cable, and measuring by using the frequency spectrograph to obtain an amplitude A2 of an electromagnetic signal at an antenna port to be corrected;
step 2: calculating an output signal amplitude A1 displayed by the signal source and a signal amplitude A2 measured by the frequency spectrograph at the antenna port, and calculating the path attenuation L between the signal source and the antenna port to be corrected to be A1-A2;
and step 3: connecting a field intensity probe with a field intensity meter, placing the field intensity probe at a position 1 m in front of the antenna to be calibrated, and measuring field intensity values C of various frequencies of the antenna to be calibrated;
and 4, step 4: calculating the difference value between the output signal amplitude B and the insertion loss L displayed by the signal source to obtain a signal amplitude B-L at the antenna port during calibration;
and 5: and calculating the ratio alpha of the signal amplitude B-L and the field intensity value C, thereby obtaining the antenna coefficient alpha of the antenna to be calibrated as (B-L)/C.
The invention has the advantages that the existing equipment of the electromagnetic compatibility laboratory can be utilized to carry out on-site calibration measurement on the antenna coefficient of the radiation transmitting antenna in the real environment of the laboratory. The calibration method provided by the invention not only avoids the problems of antenna damage, long calibration period and the like caused by antenna transportation and the like, but also ensures the reliability of the antenna coefficient obtained by calibration due to field calibration, thereby being beneficial to the accuracy of the electromagnetic compatibility radiation emission test.
Drawings
FIG. 1 is a schematic diagram of an amplitude of an electromagnetic signal at an antenna port to be calibrated measured by a spectrometer;
fig. 2 is a schematic diagram of field strength values tested at a test site.
The system comprises a signal source 1, a path attenuator 2, an antenna to be calibrated 3, a field intensity probe 4, a field intensity meter 5, a test bench 6, a test ground 7 and a frequency spectrograph 8.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings.
As shown in fig. 1, the amplitude of the electromagnetic signal at the antenna port to be calibrated is measured by a spectrometer (8). The specific calibration method is as follows:
step 1: connecting a signal source to a frequency spectrograph through a cable, and measuring by using the frequency spectrograph to obtain an amplitude A2 of an electromagnetic signal at an antenna port to be corrected;
step 2: calculating an output signal amplitude A1 displayed by the signal source and a signal amplitude A2 measured by the frequency spectrograph at the antenna port, and calculating the path attenuation L between the signal source and the antenna port to be corrected to be A1-A2;
and step 3: connecting a field intensity probe with a field intensity meter, placing the field intensity probe at a position 1 m in front of the antenna to be calibrated, and measuring field intensity values C of various frequencies of the antenna to be calibrated;
and 5: and calculating the ratio alpha of the signal amplitude B-L and the field intensity value C, thereby obtaining the antenna coefficient alpha of the antenna to be calibrated as (B-L)/C.
In the embodiment, the insertion loss of a path from a signal source to an antenna port to be corrected is calculated according to the output signal amplitude displayed by the signal source (1) and the signal amplitude measured by a spectrometer (8) at the antenna port.
As shown in fig. 2, fig. 2 is a schematic diagram of measuring field strength values of various frequencies 1 meter in front of an antenna to be calibrated on a test site by using field strength measuring equipment such as a field strength probe, a field strength meter and the like for a radiation sensitivity test in a laboratory. Keeping the path configuration shown in fig. 1, the spectrometer in fig. 1 is replaced by an antenna (3) to be calibrated, so that the antenna (3) to be calibrated radiates electromagnetic waves to the outside. In the test environment configuration of a test bench (6) and a test ground (7) in a test room, field intensity values of various frequencies at 1 meter in front of an antenna to be calibrated are obtained by measuring field intensity measuring equipment of a field intensity probe (4) and a field intensity meter (5) for the existing radiation sensitivity test in the test room. According to the output signal amplitude displayed by the signal source (1) and the previously calculated insertion loss of the path from the signal source (1) to the port of the antenna to be calibrated (3) when the antenna to be calibrated (3) emits an electric field, obtaining the signal amplitude at the port of the antenna during calibration; and calculating the ratio of the signal amplitude at the port of the antenna (3) to be corrected, which is calculated during calibration, to the field intensity value measured by the field intensity measuring equipment, so as to obtain the antenna coefficient of the antenna to be corrected.
Claims (1)
1. A method for on-site calibration of antenna coefficients of a radiated emission test antenna is characterized by comprising the following steps:
step 1: connecting a signal source to a frequency spectrograph through a cable, and measuring by using the frequency spectrograph to obtain an amplitude A2 of an electromagnetic signal at an antenna port to be corrected;
step 2: calculating an output signal amplitude A1 displayed by the signal source and a signal amplitude A2 measured by the frequency spectrograph at the antenna port, and calculating the path attenuation L between the signal source and the antenna port to be corrected to be A1-A2;
and step 3: connecting a field intensity probe with a field intensity meter, placing the field intensity probe at a position 1 m in front of the antenna to be calibrated, and measuring field intensity values C of various frequencies of the antenna to be calibrated;
and 4, step 4: calculating the difference value between the output signal amplitude B and the insertion loss L displayed by the signal source to obtain a signal amplitude B-L at the antenna port during calibration;
and 5: and calculating the ratio alpha of the signal amplitude B-L and the field intensity value C, thereby obtaining the antenna coefficient alpha of the antenna to be calibrated as (B-L)/C.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111523600.2A CN114280381A (en) | 2021-12-13 | 2021-12-13 | On-site calibration method for antenna coefficient of radiation emission test antenna |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111523600.2A CN114280381A (en) | 2021-12-13 | 2021-12-13 | On-site calibration method for antenna coefficient of radiation emission test antenna |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4673870A (en) * | 1985-08-07 | 1987-06-16 | The United States Of America As Represented By The Secretary Of The Army | Automated calibration technique for non-field perturbing (electrically small) electromagnetic field sensors |
| CN101349730A (en) * | 2008-09-04 | 2009-01-21 | 北京航空航天大学 | Method for setting signal source amplitude initial value in electromagnetic radiation sensitiveness automatic test |
| CN103605102A (en) * | 2013-11-28 | 2014-02-26 | 北京无线电计量测试研究所 | Field calibration method for radiated emission measurement antenna of electromagnetic compatibility experiment |
| CN105738708A (en) * | 2016-04-06 | 2016-07-06 | 中国舰船研究设计中心 | Short wave antenna tuner insertion loss measuring device and method |
| JP2016142609A (en) * | 2015-02-02 | 2016-08-08 | Tdk株式会社 | Far electromagnetic field estimation device |
| CN112763811A (en) * | 2020-11-30 | 2021-05-07 | 北京无线电计量测试研究所 | Detection system and fitting method for response values of antenna port and cable port of equipment |
-
2021
- 2021-12-13 CN CN202111523600.2A patent/CN114280381A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4673870A (en) * | 1985-08-07 | 1987-06-16 | The United States Of America As Represented By The Secretary Of The Army | Automated calibration technique for non-field perturbing (electrically small) electromagnetic field sensors |
| CN101349730A (en) * | 2008-09-04 | 2009-01-21 | 北京航空航天大学 | Method for setting signal source amplitude initial value in electromagnetic radiation sensitiveness automatic test |
| CN103605102A (en) * | 2013-11-28 | 2014-02-26 | 北京无线电计量测试研究所 | Field calibration method for radiated emission measurement antenna of electromagnetic compatibility experiment |
| JP2016142609A (en) * | 2015-02-02 | 2016-08-08 | Tdk株式会社 | Far electromagnetic field estimation device |
| CN105738708A (en) * | 2016-04-06 | 2016-07-06 | 中国舰船研究设计中心 | Short wave antenna tuner insertion loss measuring device and method |
| CN112763811A (en) * | 2020-11-30 | 2021-05-07 | 北京无线电计量测试研究所 | Detection system and fitting method for response values of antenna port and cable port of equipment |
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Application publication date: 20220405 |