Electromagnetic Compatibility Prediction Method Under the Multifrequency in-Band Interference Environment

An electromagnetic compatibility (EMC) prediction method is proposed to overcome the insufficiency of the single frequency threshold and prediction methods of statistical analysis. Two prediction models are established based on different sensitive parameters by analysis of the interference mechanism. Effect index is defined to predict EMC. If the effect index reaches or exceeds 1, the communication equipment will be disturbed. The radiation test platform of multifrequency in-band interference is designed, with two different types of communication radios as the equipment under test (EUT). The sine and amplitude modulation (AM) wave, dual-frequency, and tri-frequency radiation tests were performed. Test results show that the sensitive parameter of equipment can be distinguished by sine and AM wave susceptibility threshold; all of the effect indexes of EUT I which is sensitive to peak-field strength exceed 1 and all of the effect indexes of EUT II which is sensitive to average power are around 1. For reducing the model error, the modified Model I is proposed and the effect indexes of EUT I are about 1.1. The method in this paper can effectively solve the problem of multifrequency in-band EMC prediction for the communication equipment and improve EMC standards.