Research On Time Reversal Mirror(TRM) Based On Analog Signal Processing Technique

Time reversal technique is a reverse operation of the signal in the time domain.It has many applications or application potential because of the synchronous space-time focusing and super-resolution characteristics.Time reversal mirror is the key part of the time inversion system which is used to reverse the signal.In the current study,the time reversal mirror system can be divided into two categories,one based on digital signal processing(DSP)technique,the other based on analog signal processing(ASP)technique.The realization of the time reversal mirror system based on the DSP technique in the microwave band is limited by the device's sampling rate,the operating frequency,the response time,and so on.In order to solve these problems,this thesis takes the realization of time reversal mirror based on the ASP technique as the research topic,and the main research contents are introduced as follows.The first part focuses on the study of the time reversal mirror system based on the principle of time lens.Firstly,the theory of time lens is introduced in this thesis,and a simplified time reversal mirror system based on time lens is proposed.The inversion condition and the numerical simulation are carried out respectively.Then the theory and design method of chirp dispersion delay line are elaborated.The experimental system is constructed by using the chirp dispersion delay line,and the feasibility of the scheme is verified.The derivation and numerical simulation make the time inversion condition more explicit,which reduces the design difficulty of the experimental system.Compared to the original time lens system,this experimental system has lower losses and complexity.The second part mainly studies the time reversal mirror system based on instantaneous coupling.Based on the Huygens principle,a time reversal mirror system based on instantaneous coupling is proposed.The numerical simulation of instantaneous coupling system of parallel plate waveguide and advanced design system(ADS)software simulation of instantaneous coupling system of microstrip transmission line are carried out in this thesis,which verifies the correctness the principle and also provides guidance for the experimental program.Finally,the results of the experiment are introduced.Compared with general time inversion system,the scheme proposed in this thesis has the advantages of simple principle.It is not necessary to pretreat the waveform.And it is a real-time time reversal mirror,which has reference value for inverting more complex waveforms under better experimental conditions in the future.In the third part,the principal content is time reversal mirror system based on the temporal discontinuity of the time-varying dielectric.The working principle of this scheme is analyzed based on the Fresnel formula and the feasibility of the scheme is verified through theoretical analysis and numerical calculation.In addition many influence factors are discussed in this thesis,such as relative change rate of dielectric constant,medium response time and frequency.This system provides a reference for the realization of high effective and real-time time reversal mirror system.