The Reserch Of Phased Array Radar Multibeam Forming Technology

Since the advent of phased array radar, it has enjoyed rapid development because of its highlighting advantages. With forming a multi-beam, phased array radar is capable of scanning airspace quickly, controlling beam shape flexibly. These features make it not only in the radar field, but also in communications, navigation been applied, also it continue to develop. Today, phased array beam forming technology, especially digital multi-beamforming( DBF) has been played more and more emphasis by domestic and foreign research institutions and academics. In order to understand the status of phased array mutibeam technology and its formation method, the practical problems encountered in engineering, the following work has been done in this thesis:1. This thesis detailed the background of phased array radar, development history and current situation, and also explains the significance of formation of phased array radar transmit / receive multiple beams.2. Traditional as well as digital multi-beamforming approach of phased array radar has been introduced in this thesis. As we all know, there are mainly two traditional multi-beam forming: RF and IF multi-beamforming. Then, this thesis studise radar linear model and multi-beam pattern function based on the basic principles of digital multi-beam. Finally, the practical application has been introduced.3. On the basis of digital multi-beam forming algorithm, taking the transmitting /receiving multi-beam forming technology into account, this thesis analyzes some DBF algorithms as follows: FFT multi-beam forming algorithm, sub-level beamforming algorithm, adaptive multi-beam algorithm. Finally, with the help of theoretical analysis and Matlab simulation, the thesis makes a comparative analysis of the pros and cons of the three algorithms detailly.4. As one significant factor of nonlinear distortion in radar system, this paper focuses on the impacts of the RF amplifier on multi-beamforming in the final chapter. Basing on a typical power amplifier mathematical model, this thesis analyzes the mathematical expressions of the amplifier’s input and output signals, and then discusses the desired signal and the interference component after inputing constant envelope and non-constant envelope carriers in amplifier. By Matlab simulation, the impects on multi-beam forming are discussed in the case of inputing constant envelope and non-constant envelope signals in radar. Thus, this result can be a reference for designing and selecting the amplifier in paractical applications.