Electromagnetic Compatibility Analysis And Test Of U-band Mmwave Receiver Module

With the rapid development of communication technology,people have higher and higher requirements for communication equipment.The complexity of communication systems and the complex environment in which they are located have also brought great challenges to designers,and EMC has become a key factor for designers to consider.As the RF receiving module at the front-end of communication,it is necessary to avoid interference from itself and external factors in order to receive weak electromagnetic signals from the complex electromagnetic environment and convert them into IF signals.The RF receiving module should be strictly designed to avoid the occurrence of EMI as much as possible in the early frequency planning,link simulation,and layout design.However,there are always unexpected problems in the actual test.It is also very important to analyze and solve EMC problems encountered during debugging stage.In this paper,the U-band millimeter-wave receiving module designed for a project in the previous period is taken as an example,and the EMC problems encountered by the module during the test phase are discussed and studied.Through theoretical analysis,practical testing,modeling and simulation,the EMC problems involved in this module have been successfully solved.This paper has a certain reference value for the design,implementation and debugging of the RF front-end of the receiving module.The main work contents are as follows:(1)The research background and significance of EMC,as well as the research status of EMC at home and abroad are expounded.This paper studies the principles and basic concepts of EMC,analyzes and summarizes the EMC design of printed circuit boards,and provides a theoretical basis for the analysis and solution of electromagnetic compatibility problems.(2)Three types of EMC problems encountered by the U-band millimeter-wave receiving module involved in the subject are pointed out.Under the guidance of theoretical knowledge,the interference source is successfully located through the analysis of interference characteristics and sub-module investigation.Analyze the causes of interference,divide the types of interference,and take corresponding measures to solve them.(3)Aiming at the conducted interference(switching power supply frequency and frequency source fractional frequency spur)encountered by the U-band millimeter wave receiving module,by analyzing the spurious characteristics,locating the interference source,analyzing the source of the interference source,and adopting the method of suppressing the interference source,fundamentally weaken the interference intensity;for the radiation interference(frequency leakage of the frequency source feedback loop),the receiving module is modeled with the help of HFSS electromagnetic simulation software.Taking the interference source as the excitation,check the electric field distribution of the board and the surrounding space.By analyzing the simulation results,the area with high electric field intensity in the model is found,and the radiation interference problem is solved by cutting off the interference path.(4)On the basis of theoretical analysis,actual testing,modeling and simulation,corresponding processing methods are adopted for different interference types,and a test platform is built to check the interference situation.The final results show that the electromagnetic compatibility problem of the U-band millimeter-wave receiving module meets the index requirements after processing,which can ensure the correct demodulation of the IF signal at the digital end.