| Digital beamforming(DBF)and beamforming array antennas are always research hotspots in antenna technology.The two antennas have a common problem,that is,the feed network is complicated.In response to this key problem,this paper proposes a novel single-channel DBF antenna using a low-cost scanning array and a beamforming array antenna based on new amplitude-phase unit.The main research contents are as follows:1.A single-channel aperture distribution reconstruction method using a scanning array is proposed.By finding and solving the relationship between the amplitude and phase distribution on antenna aperture and the received signal sequence in single-channel,the amplitude and phase distribution on antenna aperture can be reconstructed according to the received signal sequence and antenna scanning pattern.Meanwhile,the ill-conditioned equation problem can be solved.The restored amplitude and phase distribution can be weighted in the digital domain to achieve digital beamforming,and it can be substituted into a super-resolution algorithm to achieve angular super-resolution.Experiments are carried out using a low-cost one-dimensional electronically scanned transmitarray antenna as the hardware structure,which proves the correctness and feasibility of the above-mentioned theory.2.A single-channel DBF antenna utilizing a low-cost bifocal scanning transmitarray antenna as the hardware is developed.The Gaussian weighted bifocal design method is introduced,and a bifocal scanning transmitarray antenna is designed.The antenna adopts high-speed radio frequency switches.By sequentially switching the activity of feeding elements,16 scanning beams within the range of ±27° is realized,and the gain vairation in the scanning range is small,only 1.9dB.Using the single-channel aperture distribution reconstruction method proposed in this paper,the antenna is used as a low-cost single-channel DBF antenna to realize the beamforming of the flat-top beam,and the angular super-resolution.The angular resolution is improved by more than 2.16 times compared with that without this technology.3.A beam-forming array antenna based on novel amplitude and phase unit is proposed.A new type of antenna unit that can mudulate amplitude and phase independently is proposed.Using this unit as the array element of the beamforming array antenna,a design scheme of the beamforming array antenna with simple feeder network and good beamforming performance is proposed.A 16-element beamforming array antenna using only the equal power divider is designed and simulated,which shapes a ±25° flat-top beam.The ripple in the beam is lower than 1.3dB,and the sidelobe level is lower than -13 dB. |
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