Study Of The Strong Electromagnetic Pulse Protection Key Technology For RF Front-End

Strong electromagnetic pulse can be coupled into the wireless communication devices and systems through a variety of ways,and the coupling through the RF front-end is the most serious approach.Aiming at the inadequacies in the protection capabilities of existing protection measures such as power capacity and thresholds,this paper explores the key technologies of strong electromagnetic pulse protection design for RF front-end,adopts a design method integrating transient limiting and steady-state filtering.The RF front-end protection module and limiter are preliminarily designed,and the protective properties of them are analyzed and optimized.The verification of related protection design techniques and methods is completed.And the research is of great significance for improving the reliability of wireless communication devices and systems.The first part analyzes the time domain and frequency domain characteristics of several kinds of strong electromagnetic pulses.A typical RF front-end of the S band is taken as the research object.The electromagnetic correlation characteristics of them are discussed.Then the coupling magnitude of the front door is estimated,the transmission link and the sensitive circuit are studied.Effects and mechanisms of EMP action of semiconductor devices are analyzed.The damage threshold of the sensitive device LNA is given.Finally,the existing protective measures of RF front-end are discussed.And the protection technology approach to be studied in this paper is given.The second part discusses the basic characteristics of PIN diode under different excitations,The approximate calculation formula of several main parameters of the diode is given.Based on the above research,the method to establish the transient equivalent circuit model of the diode is studied.Then the complete equivalent circuit model and the methods for obtaining and estimating each parameter are given in detail.Taking Skyworks' PIN diode as an example,the transient equivalent circuit model is established in ADS.Finally,the simulation data of the established model and the official model are compared,and the results are basically consistent.Hence,the feasibility of the modeling method is verified.In the third part,several key specifications of the PIN limiter are given first.Based on the simulation,the effects of the basic parameters of the diode on the limiter index are analyzed.The relationship between the amplitude limiting characteristics and the frequency and amplitude of the incident wave is discussed.Then the design method of PIN limiter is studied.Using the modeling approach given above,corresponding simulation models of PIN diode are established in ADS and a two-stage PIN limiter is designed.In order to realize the optimization of the protection performance,a microstrip bandpass filter is designed based on the design idea of integration of transient limiting and steady state filtering.The limiter and the filter are designed together.The comparison shows that the integrated design results are relatively good.Finally,a further optimization circuit of the integrated protection module is given and its performance is verified.In the fourth part,the basic principle and design method of waveguide PIN limiter are analyzed in detail.The effects of adding limiter unit and other reactive components on the transmission characteristics of waveguide are given,and the measures for solving the problem are also given.Then combined with the theoretical analysis and simulation design of CST,the design methods of the resonant unit composed of resonant window,limiter unit,diaphragm and metal rod are studied.The influence of the structural parameter change on the performance of the parallel resonant unit is explored through parameter scanning,and the qualitative analysis result is given.Finally,based on these basic units,the simulation and performance evaluation of the waveguide PIN limiter with both filtering characteristics are completed.