Research On Key Technologies Of Microwave Signal Processing Based On Photon Phase Shift

Microwave photonics combines photonic technology and microwave technology,and uses the advantages of photonic technology to realize higher-performance microwave devices and systems.The application of microwave photon signal processing technology to phased array radar system can overcome the problems of small bandwidth,poor phase shift,electromagnetic interference and beam deflection of traditional phased array radar.Among them,photonic radio frequency phase-shifting technology is one of the foundations for the development of microwave photonic signal processing.Based on this technology,various signal processing functions such as filtering,frequency mixing and phase shifting can be realized.At present,the research on microwave photonic signal processing system mainly focuses on the realization of a single processing function.However,signal processing in practical applications is often very complex and requires a combination of a series of processing methods.In this thesis,based on the photonic radio frequency phase-shifting technology,some schemes that can realize multiple signal processing functions at the same time are proposed.Using the single-sideband modulation technology based on double-parallel MachZehnder modulator,a microwave photonic frequency doubling phase shifter is proposed,which can realize the free conversion of fundamental frequency phase shift and double frequency phase shift by adjusting the bias voltage.And the influence of the amplitude unbalance and phase unbalance of the 90-degree hybrid splitter and the 180-degree hybrid splitter on the quality of the output radio frequency signal is explored.The simulation results show that the amplitude and phase imbalance of the 180-degree hybrid splitter has little effect on the quality of the output signal,while the amplitude and phase imbalance of the 90-degree hybrid splitter have a greater impact on the quality of the output signal.Taking into account the influence of the 90-degree hybrid splitter amplitude and phase imbalance on the signal,the frequency multiplied signal has a relatively flat amplitude response and phase response in the bandwidth range of 4-52 GHz,and can achieve 360 degrees phase tuning.When the radio frequency signal and the local oscillator signal are input to the upper and lower channels respectively,the frequency doubling phase shifting system can be used to realize the microwave photonic mixing phase shifter.By adjusting the bias voltage,the flexible switching between up-conversion phase-shifting and downconversion phase-shifting can be achieved.Combining single-sideband modulation and optical filter filtering techniques,microwave photonic phase shifters with frequency triple,quadruple,quintuple and sextuple are proposed.The simulation results show that,considering the influence of the90-degree hybrid splitter amplitude and phase imbalance on the signal,the output frequency multiplied signals all have flat amplitude response and phase response,and the phase shift range all reach 360 degrees.Among them,the amplitude fluctuation range of the obtained frequency multiplied phase-shifted signal is ±0.1 d B,the phase fluctuation range is ±5 degrees,and the frequency of the input radio frequency signal is between 2-26.5 GHz.In addition,based on optical band-pass filter filtering,a microwave photonic sub-harmonic mixing phase shifter is proposed.The high-order sideband of the local oscillator signal and the first-order sideband of the radio frequency signal are used for up and down conversion,which reduces the requirements for the microwave source that generates the local oscillator signal.