Channel Calibration Technique In The Dbf System Research

Digital beamforming (DBF) system is a perfect combination of the digital technology and antenna technology. Compared with traditional antenna, DBF antenna system has better performances in anti-interference, multi-beam, flexibility, wide dynamic range, and low side lobe. However, due to the imperfect of the DBF system, the amplitude and phase error between channels or in different carry frequencies will cause a serious degradation in performance. In this thesis, focused on DBF system, channel calibration technique is studied. The main research work can be divided into three parts:theoretical research, hardware development and software debugging, as follows:1. According to system requirements, a scheme for the channel calibration is proposed, including the hardware implementation scheme and main components selection;2. The circuit design of the channel calibration board is accomplished, including FPGA circuit, power supply circuit. AD/DA circuit and external interface circuit. The schematic circuit design and printed circuit board design are finished;3. The software flowchart on FPGA for digital T/R channel calibration is designed, and the software include self-inspection module, pulse synchronization module, and calibration module for transmitting channel and receiving channel, is programmed and debugged;4. The affection caused by the channel error in narrow band or wide band DBF system are analyzed. A channel equalization method for channel calibration in wide band DBF system is investigated, programmed and simulated. The performance is evaluated;5. By using Microblaze IP core, a software MCU is constructed to meet the requirements of channel calibration, several parts of the channel calibration is accomplished in real system.