Research On The Failure Mechanism Of Radio Frequency Connector And Its Effects On Signal Transmission

Radio-Frequency connector plays a critical role in communication systems.In recent years,with the rapid growth of consumer electronics,automobile electronics,communication terminal market and the development of 4G and 5G technology,the demand of global connector market has been increasing.Connector reliability has become an important concern in high frequency and high-speed communications.Affected by the working conditions,connectors are mostly exposed to the atmosphere.The harsh environment will cause the accumulation of contaminants on the surface of the connector,resulting in failure of the electrical contact,which will affect the signal transmission and cause the communication performance to deteriorate.The problem of electrical contact failure has become a key factor that restricts the reliability of the connector and even the entire system.Therefore,in order to analyze the problem caused by electrical contact failure and put forward solutions,this paper aims to study the mechanism of electrical contact failure of RF connector and its influence on the transmission signal from the point of view of physical mechanism.In this paper,based on theoretical analysis,model establishment,electromagnetic simulation,circuit simulation and experimental tests,the electrical contact failure mechanism of RF connector and its influence on transmission signal were studied.On account of the microcosmic surface features of the electrical contact,the relationship between the surface features and impedance parameters was established,and the failure mechanism of electrical contact was revealed based on the equivalent circuit.Considering the influence of the signal frequency,the relationship between the electrical contact characteristics of the connector and the indexes of the high-frequency electrical parameters was established,then the influence of the electrical contact failure on the transmission signal and the fault diagnosis method were studied,and the electrical contact problems of the RF connector were fully expounded.The research results can provide guidance and reference for promoting the structural optimization of RF connector.At the same time,the results in this paper not only applies to connectors,but also applies to high-frequency switches,relays,solder joints and other types of movable connections and fixed connections of high-frequency electrical contact problems.The studies have a certain theoretical and practical significance.The main research contents are as follows:1.The failure mechanism of high-frequency electrical contact was studied from the equivalent circuit point of view,and the relationship between the physical and chemical characteristics of the contact surface and the macroscopic impedance parameters was established.For the problems of electrical contact of RF connectors,starting from the microscopic characteristics of the electrical contact surface,the generation mechanism of the resistance,capacitance and inductance is explained fundamentally according to the physical mechanism.The relationships between the microscopic physical characteristics of the contact structure of the connector,the physical topology of the contact surface,the material properties,and the macroscopic electrical parameters were established.The equivalent impedance model of the failed connector was obtained,the formulae of the model parameters were derived,and the frequency characteristics were studied.The failure mechanism of the electrical contact was studied from the perspective of the equivalent circuit.Finally,the acceleration test and impedance test were designed,the impedance effect and frequency characteristics of electrical contact degradation from the actual test point of view were studied,and the theoretical results were verified.2.The high-frequency characteristics of RF connectors were studied with the method of the "circuit" and "field".The relationship between the characteristics of electrical contact failure and the high-frequency performance degradation of the RF connector was established.According to the transmission mechanism of the signal in the connector,the RF connector equivalent circuit model,equivalent transmission line model,and 3D electromagnetic field distribution characteristics were developed,respectively.Considering the characteristics of contact surface degradation,the relationship between the contact surface characteristics and the degradation of the high-frequency performance for the RF connector was set up.Experiments showed that all of the three methods can well explain the connector's high-frequency characteristics and its degradation mechanism.The results provide a theoretical basis for the design and optimization of the connector.3.The influence mechanism of connector electrical contact failure on analog signal and digital baseband signal is revealed from the point of view of signal.Based on the electrical contact failure characteristics of the connector,the calculation method of the equivalent transfer function of the faulty connector is given.Through analyzing the effects of connector failure on the attenuation,distortion,and delay of the waveforms of AM,FM,and other modulation signals commonly used in communication systems,the impact mechanism of connector electrical contact failure on analog signals was studied.The influence mechanism of connector electrical contact failure on digital signal transmission was studied,and the influence mechanism of connector electrical contact failure on digital signal transmission is studied.The experiment was designed and conducted.Besides,the theoretical analysis verified the experimental results.4.Combined with the degradation mechanism of the connector and its impact on the transmitted signal,a fault diagnosis method for the connector in communication systems was proposed.The fault signal of the connector was studied,and the sampled signal is preprocessed by the wavelet transform method,use it as the input of neural network,a fault diagnosis method for connectors in a communication system based on artificial intelligence is proposed,which can judge whether the connector fails and the location of the fault.Taking RF receiver front-end circuits as examples,it is assumed that connectors in different positions of the circuit may fail,and the impedance modulus of the connector subjected to different degrees of contamination will constantly change.Taking the range of connector impedance parameters into account,determine the failure mode,and use BP neural network classification,and finally get the diagnosis results.The results show that the proposed diagnosis method of the connector has good detection and location performance.