Measurement and analysis of site attenuation of anechoic chamber
碩士 === 明新科技大學 === 電機工程研究所 === 93 === Anechoic chamber represents a quite important factor for the accuracy and reliability of EMI radiated and RF radiated，the general researching organizations tend to build the small anechoic chamber(7m*4m*3m) for EMI testing research，on the other hand，the authorize...
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| Format: | Others |
| Language: | zh-TW |
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2005
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| Online Access: | http://ndltd.ncl.edu.tw/handle/84083892962766677524 |
| Summary: | 碩士 === 明新科技大學 === 電機工程研究所 === 93 === Anechoic chamber represents a quite important factor for the accuracy and reliability of EMI radiated and RF radiated，the general researching organizations tend to build the small anechoic chamber(7m*4m*3m) for EMI testing research，on the other hand，the authorized testing organizations prefer to build full anechoic chamber (9m*6m*6m) for RF radiated certification。
This thesis is focus on the general small semi anechoic chamber (7m*4m*3m)，measures its site attenuation (SA) ，analyzes the difference between the measured site attenuation value 、the standard loss value of the free space of the small anechoic chamber and the site attenuation value of BS EN50147-2 standard 10M anechoic chamber。We also put the proper Pyramidal absorbers on the half anechoic chamber to form a small full anechoic chamber and discuss the SA difference between the small full anechoic chamber and semi anechoic chamber。The result of radiated spurious emission measurement is a relative value，the accuracy is depended on the testing environment and the SA of the testing equipment，This research also establishes a radiated spurious emission testing structure，discusses the attenuation value of the connected line, the attenuation value of the testing environment，and evaluates the accuracy of the test。
For EMI，the difference of SA between the small full anechoic chamber and small semi anechoic chamber is within ±4dB in some frequency range when the height，vertical, and horizontal of transmitter and receive antenna are changed。Therefore，the calibration factor can be used to describe the SA of the standardized test field. For the measurement of spurious emission for radiated, the established testing structure can measure accurately and reduce uncertainty factor。Compensate the attenuation of measurement to spectrum analyzer can gain a more confident measured result，and raise the speed and accuracy of testing。
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