混响室校准测试

混响室用于辐射干扰测试,以其造价便宜、测试重复性好等优点越来越受到广泛的重视,深入开展混响室的优化设计、测试方法、统计理论等方面的研究,可为更规范应用混响室测试方法提供科学的依据。为研究混响室在使用之前需要进行的校准测试,以评估其性能,并获得几个重要的校准参数,利用清华大学建造的混响室,从场均匀性,天线校准系数,品质因数等方面评价空腔混响室的性能。进行4次测试的结果表明设计的混响室品质因数高,电场均匀性良好。测试的重复性非常好,建造的混响室能够很好的用于电磁兼容测试。

Calibration Test of Reverberation Chamber

The Reverberation Chamber (RC) testing exhibits several competitive advantages over existing methods, such as the fascinating low cost of construction and the enhanced test repeatability. The application of the reverberation chamber requires a calibration before the EMI/EMS tests. A statistical analysis of the calibration data proves the field homogeneity in the working volume and provides the necessary parameters for EMI/EMS tests. The calibration consists of two parts, field strength and power measurements of the empty chamber and the same measurements of the chamber with the maximum loading. Prior to each test, the chamber has to be calibrated in order to prove that it is not adversely loaded by EUT. A prototype RC with a measurement system is built according to the simulation analysis and calibrated in terms of IEC standard. The key parameters such as field uniformity, quality factor, the average normalized electric field and the receive antenna calibration factor are analyzed in detail. Four different work volumes and methods of sweeping frequency are applied. It is indicated that the key parameters of the reverberation chamber have good testing repeatability and this will ensure good test repeatability for electromagnetic susceptibility test and electromagnetic emission test. The test results also show that the quality factor of the reverberation chamber is up to several thousands above the lowest useful frequency. All test results reveal that this reverberation chamber conforms to the specification of the IEC standard and can be used in the common EMC test.