Analysis Of Influence Of EUT Electrical Size On Uncertainty Of Reverberation Chamber Immunity Test

The Reverberation chamber has significant advantages such as larger test space,lower cost and shorter test time compared with the anechoic chamber test system.However,the lager test uncertainty in the reverberation chamber limits its further application.The topic of this paper is focus on the influence of the EUT(equipment under test)electrical size to the uncertainty of reverberation chamber immunity test.The work done by the thesis are listed as follows:1.Basic principle of the angular spectrum is introduced,then the probability distribution function of the field intensity and the received power of EUT in the reverberation chamber is derived.After that,the relationship between EUT received power and field strength is obtained.2.Through statistic theory,the inherent uncertainty of the field strength and the received power of EUT based on the maximum value and the average value is obtained.Then the uncertainty caused by the equipment and facilities during testing is analyzed and the extended uncertainty is derived.Next immunity test is carried out in the reverberation chamber using the horn antenna whose basic parameter is known as EUT.The received power of the antenna is within the uncertainty range,which verifies the correctness of the theory above.3.Basic principle of plane wave superposition theory is presented and the test environment which is the same as that in the reverberation chamber is built using plane wave superposition theory in MATLAB.Besides,whether the field distribution function created in MATLAB is the same with the distribution in reverberation chamber and whether the field uniformity meets the requirements are verified using the K-S test method.After that,the dipole antennas with different electrical size are used as EUT,and its terminal received power is simulated in MATLAB several times which is equal to the number of samples in reverberation chamber.Then solve the normalized standard deviation of received power.4.Simulate reverberation chamber in the software of FEKO,build a reverberation chamber whose size is the same as the experimental test and simulate its field uniformity.Calculate the theoretical field strength value by input power and reverberation room Q value and compare it with simulation value to verify the rationality of the simulation.Using dipole antenna with different electric length as EUT and solve the normalized standard deviation of the received power in different stirring positon.5.Improve the LabVIEW program of field uniformity calibration and immunity test in reverberation chamber by adding field strength monitoring module and power meter output stabling module.The LabVIEW program of immunity test in anechoic is written which can control the rotation of the turntable and achieve the continuous test.6.Calibrate the field uniformity of the reverberation chamber and make different type of EUT,carry out the immunity test and repeatability test with the EUT,analyze test uncertainty and compared with each other.7.In the process of anechoic immunity test,the antenna have the status of vertical and horizontal polarization,the test site have two status of whether add the absorbing material.Carry out the immunity test in anechoic respectively in four different status and compared with each other.Use the software of CST to simulate the directivity of EUT and compare the test results of reverberation chamber and anechoic for consistence.