Research On Subarray Beam Steering System Of Active Phased Array Radar

Phased array radar, also known as electronic scanning radar,refers to the radar can implement beam scanning by control antenna’s excitation current. Compared with mechanical scanning radar, beam scanning of phased array radar is agile, fast and can scan multiple areas simultaneously. Beam steering system is the key for phased array radar to carry out the functions. With the development of phased array radar technology, beam steering system needs to meet many conditions, such as high response speed, structure miniaturization and so on. Beam steering system based on LSI(Large Scale Integration) become the mainstream of development direction. The subarrary beam steering system of active phased array radar is studied in this paper, and the thesis is organized as follows.First of all, principles of beam steering for phased array radar are investigated. Composition, types and requirements of beam steering system are introduced. Theory of the linear and planar arrays is considered to derive the calculation method of beam steering codes, and the correctness of the calculation method is proved by the simulations. Virtual-bit method is applied to improving the accuracy of beam pointing. Influence on the antenna beam, which is caused by virtual-bit method, is analyzed through simulations. Several factors are discussed, which can cause errors to antenna beam direction, and some methods are proposed to correct the errors.Then, the implementation method of beam steering system based on FPGA(Field Programmable Gate Array) is analyzed. The design proposal of beam steering system is proposed, and the hardware platform is introduced respectively. The time control sequence of T/R(Transmitter and Receiver) modules is designed, and each sub-module of the time control sequence is verified to be effective by the simulations. Beam steering codes are calculated in FPGA, virtual-bit method and error compensation data are taken into account in the calculation process. Simulations show the beam steering system can control T/R modules according to the command data.Finally, testing of the beam control system is completed. Upper computer is designed to send beam steering codes and maintain surveillance on the system’s operating state. Testing scheme of the beam steering system is finalized, including building the test circuit, testing T/R modules’ status and so on. Effectiveness of the system is demonstrated by analyzing the test results.