Research On EMC Antenna Measurement System Based On High-Performance OATS

The EMC antenna factor measurement uncertainty will directly affect the accuracy of the radiation emission test of the electronic product. And the measurement uncertainty of the antenna factor is related to the test methods, measurement software, instrument, the performance of the test site and other factors. Therefore, this thesis focuses on the research to the measurement uncertainty of antenna factor and the measurement software.Firstly, for the moment, there is no corresponding commercial measurement software to the antenna factor test on the market. So, this thesis researched a highly efficient antenna factor measurement software based on the test method and test site of the National Institute of Metrology, China. The software can simplify testing operations and improve test efficiency.The function of the software are:tower speed control intelligently; data acquisition, antenna height scanning, max hold, data storage and fill naming will accomplished automatically; analysis and process the test data timely; generate a certification rapidly, act.Secondly, according to the current international antenna calibration method Standard Site Method(SSM) and the Reference Antenna Method(RAM), this thesis researched the measurement uncertainty of the antenna factor by the following factors based on a high performance Open Area Test Site of the National Institute of Metrology, China.1、Error from R2、Cable Loss3、 Impedance Mismatch4、Site&System Standard Deviation5、Background Noise6、S21of VNA7、Coupling Between the Transmit Antenna and the Receive Antenna8、Coupling Between the Antenna and the GroundAccording to the research results we know that using the Standard Site Method to calibrate a biconical antenna, whose uncertainty is about0.7dB, and for a LPDA is within0.9dB. To calibrate a biconical antenna with the Reference Antenna Method, whose uncertainty is within1.2dB, and for a hybrid antenna is within1.6dB in the high frequency. In addition, through the analysis and research to the impact of various factors on EMC antenna factor, we put forward the corresponding improvement measures to optimize the test methods.Finally, the MOM was used to simulate and investigate the effect of the reflection of the trees, the reflection of the antenna tower, the plane-edge metal mesh and the polarization error to the EMC antenna test. According to the simulation results, the effect of the plane-edge metal mesh is about0.05dB from30MHz to100MHz, and it is much better with a narrowest mesh. In addition, as the polarization error is less than5°, its impact is also within0.05dB from30MHz to100MHz. The effect of the trees reflection around the site is within0.2dB. These analyzes provides a theoretical basis for the optimization of the site performance and the antenna measurement.