Design And Implementation Of Phased Array Radio Frequency Self-Interference Cancellation Circuits

Nowadays,the spectrum resource is in exhaustion.The Co-time Co-frequency fullduplex(CCFD)technology can double the spectrum efficiency because the technology can simultaneously transmit and receive signals in the same frequency band.Therefore the technology becomes a hot spot in communication fields.But in the CCFD systems,the strong self-interference signals need to be canceled to a reasonable range.As a set of antenna arrays that can flexibly implement beam pointing,the phased array technology can be combined with the Co-time Co-frequency full-duplex technology to further improve the spectral efficiency.However,due to the array antenna characteristics of the phased array,the self-interference cancellation technology in the phased array scenarios still faces many challenges.In the phased array radio frequency self-interference cancellation,the radio frequency front-end of the receiving channel of the system is more likely to be saturated,and the nonlinear distortion and noise will be more serious,which has higher requirements for the design of the radio frequency circuits.Therefore it is of great significance to study the self-interference cancellation problem of the phased array.This thesis mainly studies the phased array radio frequency selfinterference cancellation,designs and validates the phased array radio frequency selfinterference cancellation circuits.The work of the thesis is as follows:Firstly,the theoretical basis of phased array radio frequency self-interference cancellation is analyzed.The key technologies and foreign research methods of phased array radio frequency self-interference cancellation problem are analyzed in detail,and their pros and cons are compared.Then the self-interference cancellation model is established,the self-interference cancellation performance in multiple input and single output scenario is theoretically deduced,and the impact of engineering errors is simulated.Secondly,the phased array radio frequency self-interference cancellation circuits is designed and implemented.According to the application scenarios,the overall requirements of radio frequency self-interference cancellation circuits are put forward with reference to the theoretical analysis.Also,the self-interference cancellation circuits is designed in detail according to the overall requirements,including important work such as device selection,link budget,and index analysis.Then,referring to the detailed design,the hardware development of the entire phased array radio frequency self-interference cancellation circuits is completed.Thirdly,build the phased array radio frequency self-interference cancellation experimental platform and complete the system test verification.The phased array radio frequency self-interference cancellation circuits achieves up to 43 d B,36 d B,and 18 d B of self-interference performance in the radio frequency for single-tone signals,2MHz linear frequency modulation(LFM)signals and 40 MHz LFM signals with a center frequency of 3GHz in the phased array multiple input single ouput scenario.In summary,this thesis designs and implements phased array radio frequency selfinterference cancellation circuits,which provides reference for the subsequent theoretical research and hardware implementation of phased array radio frequency self-interference cancellation technology.