TEM室法环天线校准系统建立及测量结果不确定度评定

横电磁波室法是9kHz~30MHz频段环天线校准中广泛采用的一种方法。环天线分为有源环天线和无源环天线两类,这两种天线的磁场天线系数在量值范围上差别大,对系统动态范围要求不同。根据这一特点,对两类环天线分别建立横电磁波室作为标准场的环天线校准系统,基于网络分析仪开展扫频测量。针对电磁兼容领域中常用的直径60cm以下有源和无源环天线分别开展校准方法研究,给出磁场天线系数测量结果和测量结果的不确定度评定。该环天线校准系统可以扫频完成常用环天线在9kHz~30MHz频段内的校准,解决大动态范围问题,环天线校准效率也得到提高。

The Loop Antenna Calibration System Using the TEM Method and the Uncertainty Estimation for the Measurement Results

The transverse electromagnetic (TEM) cell method is widely used in the loop antenna calibrations. The system dynamic range requirement for the active loop and the passive loop are different due to the magnetic antenna factor difference. Two new loop antenna calibration systems based on the TEM cell as the standard field generator have been proposed considering the magnetic field antenna factor difference for active and passive loop respectively, which enable the sweep-frequency measurement. The calibration methods are discussed,the measured magnetic field antenna factors are presented, and the uncertainties are evaluated for the active loop and the passive loop of no more than 60cm diameter which is normally used in the electromagnetic compatibility (EMC) field, respectively. The sweep-frequency measurements covering from 9kHz to 30MHz for the commonly used loop antennas can solve the problem due to the big dynamic range, and also enhance the calibration efficiency.