Wideband Constant Beamwidth Beamforming Algorithm And Its Implementation

Wideband digital array radar is a kind of fully digitized phased array radar in which wideband digital beamforming technique is used both in transmitting and receiving. The wideband digital array radar is highly flexible due to full digital processing, and it offers a number of attractive features than conventional phased array radar. In this paper, the algorithm of wideband constant beamwidth digital beamforming is studied, and the implementation of digital beamforming system in wideband digital array radar is discussed.First, the mathematical models of the signal arriving at the array are introduced, and the performances of LCMV-SMI narrowband adaptive beamformer are analyzed through simulation. Then, the structure and characteristics of wideband beamformer which implementation in frequency and time domain are analyzed, and the constant beamwidth beamforming design method which based on frequency subband division is studied in detail. In this method, constant beamwidth weighted on center frequency point of each subband via second-order cone programming is first designed. Then a FIR filter is designed to fit the constant beamwidth weighted on these frequency points to achieve wideband beamformer based on the FIR filter. In the end, the implementation methods, which include the methods of the high-speed serial transmission system based on RocketIO GTP, narrowband adaptive digital beamformer and wideband constant beamwidth digital beamformer based on a FIR filter, are discussed.