Research On The Failure Mechanism And Performance Degradation Law Of Double Coaxial High Frequency Electrical Connectors In A Storage Environment

Double Coaxial High Frequency Electrical Connector is widely used in signal transmission of military systems such as aviation,aerospace,weapons,and other electronic equipment systems due to its high anti-interference and high transmission rate.The evaluation of the reliability of high-frequency electrical connectors stored with the bomb for a long time has become the focus of research,and the premise of accurately evaluating the reliability of high-frequency electrical connectors is to clarify the failure mechanism and the degradation law of its main performance under storage conditions.Thus,this paper takes GJB599 I series double coaxial high frequency electrical connectors as the research object,investigates the main failure mechanism during storage,establishes the accelerated degradation model of key performance indicators,and concludes the research on the performance degradation law of high frequency electrical connectors under storage environmental stress.To begin,this paper summarizes the development history and research status of reliability technology and accelerated testing,introduces the research status of failure mechanism and performance of high-frequency electrical connectors,identifies the current shortcomings in the research of performance degradation of high-frequency electrical connectors,then expounds on the research objectives of this paper and summarizes the main research contents.To investigate the primary failure mechanism of the Double Coal High Frequency Electrical Connector,the storage profile was thoroughly examined,and temperature was identified as the primary environmental stress during storage.Beginning with the assembly,the failure modes are investigated from three perspectives: shell,insulator,and contact,with the contact ultimately determined as the primary failure component through experiment and simulation.When combined with storage stress,it is discovered that the main mechanism of contact performance degradation is that the base copper material diffuses to the contact surface and reacts with oxygen for an extended period of time,resulting in the formation of an oxidation corrosion film.Contact resistance and insertion loss are chosen as the primary performance indices to characterize the conduction and signal integrity performance of high-frequency electrical connectors,respectively,and the degradation law of their performance is investigated.The relationship between oxide film thickness and time is deduced from the failure mechanism analysis results using the tunnel effect theory and electrical contact theory.The contact resistance degradation trajectory model of high-frequency electrical connectors in storage is derived from the relationship between film resistance and film thickness,and the accelerated performance degradation model of contact resistance is established by combining with the acceleration equation.(Arrhenius equation).The influence of oxidation corrosion film thickness on contact area impedance in storage environment establishes the degradation law of contact area impedance.The degradation trajectory model of insertion loss performance of the entire high-frequency electrical connector at a fixed frequency is established using transmission line theory and the transmission matrix cascade algorithm,and the accelerated performance degradation model of insertion loss is obtained by combining with the acceleration equation under temperature stress.To validate the model,the contact resistance and insertion loss performance degradation law of a double coal high frequency electrical connector at storage temperature are studied,and four groups of constant stress accelerated degradation tests at different temperature levels are designed.Statistical methods such as probability graph test and numerical test are used to validate the model’s effectiveness by testing the distribution of the performance degradation model,acceleration equation,and degradation parameters.Simultaneously,the unknown parameters of two temperaturestressed performance degradation models are determined using the least square estimation method and the maximum likelihood estimation method,and the degradation curves of DC contact resistance at 25°C and insertion loss at 250 MHz are extrapolated using the acceleration equation.It is concluded from analysis and comparison that insertion loss and contact resistance have a similar degradation trend,but the degradation rate of insertion loss is faster than that of contact resistance,so measuring the contact performance of high-frequency electrical connectors with insertion loss in the frequency band of 250 Mz is more reasonable.The surface morphology of the contact after the high temperature test was observed by scanning electron microscope at the end of this paper,and the energy spectrum analysis of the area with corrosion deposits and the area without corrosion deposits was performed separately.The results show that there are pores and metal oxides on the contact surface,and the copper and oxygen contents in the corrosion deposits are higher than in other areas,confirming the failure mechanism.Finally,the research contents and innovations of this paper are summarized,and the research’s shortcomings are anticipated.