Research On Nonuniform Array Configuration Design And Digital Beamforming Technique

Array antennas,as the core components of wireless systems,significantly enhance the overall performance by carefully designing and arranging multiple antenna units.They offer advantages such as enhanced reception,high directionality,and interference suppression.Array signal processing,as a significant branch of signal processing,finds wide applications in fields such as communication,radar,and geophysical exploration.Looking ahead,traditional single,centralized uniform arrays face numerous challenges and limitations in handling diversified and complex signal processing tasks.These challenges include high engineering costs,performance degradation in complex environments,and insufficient scalability and adaptability of systems.Therefore,researching more flexible and efficient array structures and array signal processing solutions to meet the increasingly growing communication and sensing demands poses an important and challenging task.Against this backdrop,this dissertation conducts in-depth theoretical and methodological research addressing issues such as non-uniform array configuration design,static digital beamforming,and distributed multi-subarray joint array signal processing.The main innovations achieved are as follows:1.In order to optimize the configuration of non-uniform array,an array design method considering the antenna positions and transmission power is proposed.An modified membrane optimization algorithm using parallel execution strategy is used to optimize the performance of the array antenna.In addition,a general comprehensive optimization model for non-uniform arrays with multiple practical constraints is constructed,and a modified iterative coordinate descent optimization framework is proposed.This framework not only has a concise and universal algorithm structure but can also be applied to beamforming synthesis of both sparse and thinned arrays.Compared with traditional heuristic algorithms,the proposed method offers a more explicit and streamlined process without the need for tedious parameter adjustments.2.The study focuses on synthesizing beampattern with controlled sidelobes to address the issue of digital beamforming under constant mode weighting control at the transmitting end of non-uniform array.By introducing auxiliary variables and transforming constant mode constraints,the alternating direction multiplier method is used to efficiently solve the beampattern design problem.To meet diverse application requirements of digital beamforming at the receiving end of non-uniform array,a general beampattern design method based on template matching is proposed.Effective synthesis of different characteristic receiving beampatterns is achieved by minimizing the matching error between expected templates and designed beams under array gain constraint.3.A phased-MIMO radar system with non-uniform subarrays was studied to address scalability and adaptability challenges in distributed array signal processing.A hybrid optimization scheme combining subarray layout and receive beamforming was proposed to solve the problem of high sidelobe caused by large aperture sparse subarrays.Besides,a thorough investigation was conducted for targeting rapid and precise target detection within sparse phased-MIMO radar systems.A wide transmit beam is used to quickly cover the target area,and a high-resolution beam is formed at the receive end to accurately detect the target.By designing the phase and amplitude of digital domain weighting coefficients,the low sidelobe multi-beam receiving of sparse phased array-MIMO radar system under single transmission is realized.4.To meet the stringent angular resolution demands of radar systems,a virtual largeaperture non-uniform array comprised of multiple sparse subarrays was synthesized via a distributed cascaded configuration.The general Bartlett spatial spectrum expression of virtual arrays was derived,and the relationship between radar spacing,transmitter/receiver quantity,and sidelobe position in the spatial spectrum was thoroughly explored,which provides an important reference for the design and optimization of high angular resolution of radar systems.5.Various spatio-temporal-frequency amplitude synchronization errors inherent in non-uniform arrays were scrutinized,leading to the proposal of a novel statistical evaluation metric based on the mainlobe synthesis efficiency.The influence of key parameters such as carrier frequency,beam direction and number of subarrays on the error boundary is discussed.Robust beamforming methods,tailored to address different types of position errors,were introduced to optimize performance in real-world scenarios.