Study On Modeling And Simulation Methods For Characterizing Electromagnetic Interference Process Of Communication Systems Operating In Complex Electromagnetic Environment

In the 21st century,with the wide applications VHF/UHF,microwave and millimeter-wave communication systems on various large platforms,such as warship,aircraft and satellite,etc.,the requirements for modeling and simulating different electromagnetic interference processes in the systems are indeed necessary,and these studies directly support electromagnetic compatibility(EMC)as well as electromagnetic protection design from system to platform levels.This thesis is focused on studying on modeling and simulation methods for characterizing electromagnetic interference(EMI)process of communication systems operating in complex electromagnetic environment,where Matlab's Simulink framework is adopted for building different behavioral models of the system.Its main researches and innovations are summarized as follows.(1)The techniques of digital signal modulation and RF front-end channel model construction used in communication systems are introduced at first,and different EMI signals are described during the operating process of the system for further developing their link-level models.(2)An input-output model is built for a typical spread spectrum communication system,and the effects of white noise and other intentional electromagnetic interference(IEMI)are investigated numerically,with the system's anti-IEMI capability clarified.(3)For the real scene within multi-antenna and multi-station working simultaneously,the effects of same-and near-frequency EMI on the VHF/UHF communication systems are studied.Their requirements for different carrier frequency spacings corresponding to different modulation modes are identified and discussed.(4)Under the attack of high-power microwave(HPM)or strong electromagnetic pulse(EMP),the radiation coupling process between EMP and communication system antenna is measured and studied.The behavioral model of the communication system,including limiter and low noise amplifier,etc.,is successfully built.The effect of performance degradation of sensitive devices in the receiving channel on the link performance of the whole communication system is further studied,in particular the degradation of Bit Error Rate(BER)with signal delay in the system.The behavioral models of the communication systems under different EMIs have been used in the VHF/UHF systems on certain platform provided by industry institute to support their design of EMC,spectrum management and electromagnetic protection.