被试品辐射发射试验点位对测试结果影响

为提高试验精度,减小电磁兼容(EMC)半电波暗室中被试品(EUT)的电磁辐射发射试验点位对测试结果的影响,研究了不同试验点位对半电波暗室典型谐振频率电磁信号辐射发射的影响规律。采用几何光学、一致性绕射理论和多路径效应算法对不同试验点位,暗室典型谐振频率电磁信号的传输过程进行数学建模,剔除直射场强影响,综合考虑信号传输过程中产生的反射、折射、绕射和多径等电磁传播效应,给出了数学模型和计算公式。将数学传播模型与剔除直射场影响的试验实测模型计算结果进行比对,验证了数学模型的有效性。该研究为修正被试品在暗室内不同点位进行辐射发射试验的测试结果提供了理论依据,有助于提高被试品电磁辐射发射试验的测试精度。

Influence of EUT radiated emission testing location on test results

In order to improve the measurement precision and reduce the influence of equipment under test (EUT) electromagnetic radiated emission testing location on test results in electromagnetic capatibility (EMC) semi-anechoic chamber, this paper studies the influence law on electromagnetic signal radiation emission testing of semi-anechoic chamber typical resonance frequency for different testing locations of semi-anechoic chamber. The research is modeled, simulated and calculated by geometrical optics, consistency of diffraction theory and multipath effect algorithm. The math model and computational formulas are proposed, besides, the influence of direct field is eliminated in the math model. The electromagnetic propagation effects of reflection, refraction and multipath effect in the testing are comprehensively considered. The calculation results of math propagation model and actual testing model that eliminate the influence of direct field are compared. The results verify the effectiveness of math model. This research supplies theory basis for correcting the results of electromagnetic radiation emission testing in different positions of semi-anechoic chamber, which is also helpful to improving the measurement precision of electromagnetic radiation emission testing in semi-anechoic chamber.