FPGA implementation of a phased array DBF using a latch method

Abstract

Timing resolution plays a significant role in generating digital phased array beams. We present a latch method for FPGA implementation of digital beamforming (DBF) for an ionospheric radar. The radar requires a constant phasing vector to steer the beam over a specified region of the ionosphere. Sixteen digital beams are derived from the vector with beam resolution of approximately three degrees. The phasing weights can be employed either in the time domain or in the frequency domain. Comparison of phase delay and time delay methods is presented for broadband frequencies of the radar. Performance of the proposed DBF system is presented, including speed limitations.