Research On The Simultaneous Transmission And Transmission Leakage Suppression Technology Of Digital Array Antenna With Common Aperture

Compared with the traditional half-duplex radar system,the common-aperture simultaneous transmitting and receiving radar is expected to double the spectrum efficiency.In the continuous wave working mode,the common-aperture simultaneous transmitting and receiving radar needs to receive the echo signal while transmitting the signal.In order to realize this demand,there are still many problems to be solved.The key to the simultaneous transmission and reception of common-aperture antennas is the suppression processing of transmitted leakage signals(strong self-interference signals).Based on the digital array antenna of a scientific research project,this thesis studied the transmission leakage suppression technology in the digital common-aperture simultaneous transmission and reception mode of the array antenna.Two different beamforming algorithms are proposed to improve the transmission and reception isolation,aiming at transmission leakage of conventional scanning beams and synthesis beams.The main work and innovations of this thesis are as follows:1.A two-stage self-interference suppression transmit beam forming method for conventional scanning beams is proposed.This method the isolation of the transceiver while maintaining the high gain of the antenna,meanwhile the transceiver isolation of the array can be increased to 95 d B,when the maximum gain of the array is reduced by about 1.5 d B.2.An optimization criterion for residual self-interference suppression for conventional scanning beams is proposed,and a receiving beamforming algorithm is designed.The algorithm can further suppress the transmission leakage from the receiving end according to the magnitude of the residual self-interference,and increase the transmission and reception isolation to 80 d B.3.A beamforming method for transmitting leakage suppression for synthesised beams is proposed.This method combines the alternating projection pattern forming method with the residual self-interference suppression criterion to realize the antenna beam direction in the scenario of simultaneous transmission and reception of the common aperture.Requirements for graph shaping.Under the condition of pattern shaping,the transceiver isolation can be increased by 20 d B.4.Using Matlab and HFSS full-wave electromagnetic field calculation software to model and simulate the antenna system,the self-interference suppression effect under different transceiver array arrangements and different beam requirements is verified.Simulation shows that under conventional beamforming conditions,the two-stage self-interference suppression transmit beamforming algorithm and the residual interference suppression beamforming algorithm can improve the transceiver isolation by about 70 d B.Under the pattern synthesis conditions,the transmission and reception isolation can be increased by 20 d B.