Antenna calibration and digital beam forming technique of the digital array radar

The digital array radar (DAR) is a fully digitized phased array radar in which digital beam forming technique is used both in receive and transmit. A lot of simulations are made about the influence of amplitude-phase error on the antenna pattern, since amplitude-phase error of the antenna will severely affect the performances of the digital array radar. Based on the far-field external monitoring principle, the amplitude-phase error calibration method of the digital processing is studied, and the “in-the-field calibration” method, combining the reference data and the mid-field monitoring, is finally presented. Besides, the key techniques of the real-time DBF based on the FPGA processing platform are analyzed. The test results show that by using the method proposed, the high-precise calibration data can be obtained and the antenna beam after calibration can meet the digital array radar's requirements, and moreover the FPGA processing platform can realize the real-time multi-beam processing. It is a probe that the method combines the reference data and the mid-field monitoring, which is a simple, feasible and effective method for the digital array radar in the field calibration.