Investigation Of Uniform Field Strength Region In Reverberation Chamber For Electromagnetic Environment Evaluation

The extensive use of high-frequency wireless electronic equipment generates new electromagnetic interference sources,and there is an urgent need for better electromagnetic environment simulation technology to simulate the electromagnetic environment in the real world.The reverberation chamber is one of the technologies that can better simulate the real world,and can more accurately realize the electromagnetic compatibility test.The reverberation chamber can form a test environment with a statistically uniform electric field,and has many advantages such as low cost and strong field strength.Before building a reverberation room,it is often necessary to design simulation modeling,design its external dimensions,stirrer parameters,antenna parameters and other content to achieve the best performance.The previous research on reverberation rooms mainly used simulation and experimental optimization methods to improve the performance of the reverberation chamber such as uniformity of field strength.However,the method research on how to determine the uniform field of the test region of the reverberation chamber has not been reported.Because the IEC 61000-4-21,the international standard of electromagnetic compatibility testing and measurement techniques of reverberation chamber test methods,only specifies the upper limit of the test region,the actual test region is not mentioned.In the actual test,the available region after calibration of the field strength uniformity of the reverberation chamber is often not fully occupied,so the determination of the actual test region is very important.Therefore,when using a device under test that is smaller than the available region,where to perform the test becomes an urgent problem to be solved.In response to the key issues and challenges,this thesis conducted a research on classification and location method of uniform field strength region in reverberation chamber,and achieved the following results:(1)This thesis proposes a simulation analysis method for the uniform field strength region in reverberation chamber.Based on this simulation method,the qualitative optimization of the mechanical stirrer's folding number and segmented appearance was carried out,and the final designed reverberation chamber of 4.87 m*3.87 m*2.78 m,at 150?450 MHz,satisfies the field strength uniformity required by the IEC 61000-4-21 standard,and the field strength uniformity index is only 2.1852 dB,which provides a reference to the design and the construction of reverberation chamber.(2)This thesis proposes a generalized field strength uniformity index based on the test requirements of actual engineering applications.And,this thesis proposes a classification and positioning method of uniform field strength region in reverberation chamber of a one-dimensional sensitive uniform field strength region,a two-dimensional sensitive uniform field strength region,a three-dimensional sensitive uniform field strength region and a three-dimensional non-sensitive uniform field strength region which based on radiation immunity test,radiation emission test,antenna efficiency test and shielding effectiveness test.Using the data obtained from a single simulation,this model was established with an accuracy of 0.01 m.And,the coordinates of the best uniform field strength in typical four application scenarios was determined.This method has the advantages of fast solution speed and convenient calculation.At the same time,in combination with practical applications,a method for solving and positioning the spherical uniform field strength region is proposed.In the example,the field strength uniformity performance of the same volume of the region to be measured is improved by 0.34 dB.It provides a reference for the determination of the specific test region location of different equipment under test in the actual test plan of the reverberation chamber,and provides a way of thinking for the determination of the uniform field strength region of irregular shape,so that the actual test results of the reverberation chamber are more accurate and reasonable.(3)This thesis designs a complete set of integrated test system for reverberation chamber,and elaborates the framework and basic principles of the system.At the same time,an integrated test software for the test system has been developed,through which the uniformity of field strength,radiation immunity and radiation emission can be automatically calibrated or tested.This software also has clear instruction and logic.This software provides a convenient and quick method for the practical application of the reverberation chamber.