Research On The Theory And Application Of New Type Array Antenna

Since the 21 st century,with the rapid development of electronic technology and communication technology,array antennas with low cost,multi-function and high adaptability have become a new development trend.The traditional array antenna technology has been difficult to meet a variety of mutually restricted performance requirements,the industry urgently needs to explore new antenna technology.In this context,the new type array antenna technology arises at the historic moment.On the basis of the traditional array antenna,the new type array antenna introduces new degrees of freedom to replace the traditional array antenna in some complex applications,such as polarization control,time control and frequency control.Under this background,the theory and application of time-modulated array(TMA),frequency diverse array(FDA)and time-modulated frequency diverse array(TM-FDA)are studied in the thesis.The main contents of the thesis are as follows:(1)The technical method of secure communication based on TMA is studied.In order to solve the problem of signal leakage in the traditional array's sidelobe,the thesis uses a TMA to realize secure communication.So that the signal in the desired direction is not affected by time modulation and can be transmitted without distortion.On the other hand,the spectrum of the signal in the non-target direction is aliased and the signal is distorted.Based on the above method,the waveform,spectrum and bit error rate performance of digital signals transmitted by TMA are verified under the modulation of two different time series.(2)The technical method of realizing low probability of intercept secondary radar with FDA is studied.In view of the possibility that the traditional secondary radar signal is intercepted by non-cooperative aircraft,the thesis proposes to use the FDA as the transmitting antenna of the secondary radar to transmit the query pulse and control pulse of the secondary radar with different frequency offset parameters.The cooperative receiver receives the interrogation pulse by multi-channel and mixing-matched filtering,which can determine the interrogation mode on the ground.And the direction of the incoming wave can be determined by the relative intensity of the control pulse.The numerical simulation results show that the FDA can disperse the pulse signal energy into the frequency domain and achieve low interception performance.(3)The synthesis method of low sidelobe point focusing beam based on TM-FDA is studied.In order to solve the problems that there is radiation grating lobe in the transmitting beam of linear frequency offset FDA,and the decoupling effect of nonlinear frequency offset is not obvious.A method of low sidelobe spot focusing beamforming based on TM-FDA is proposed in the thesis.Genetic algorithm(GA)is used to optimize the control time sequence and frequency offset parameters of TM-FDA antenna simultaneously.And the low sidelobe spot focusing beam is realized in distance-angle dimension.The numerical simulation results show that the low sidelobe point focusing performance of the TM-FDA is obviously better than that of the general FDA.