Quantization Analysis for Reconfigurable Phased Array Beamforming

In reconfigurable phased array radars beamforming is performed in the digital domain. Digital implementation can be carried out using finite precision and infinite precision representation of the phased array signal. We consider finite precision representation, since it takes considerably less implementation resources compared with the infinite case. In this paper we analyze quantization effects when quantization is introduced in the phasing network. The quantization problem is extensively addressed in the literature for phased array radars. But it mainly focuses on steering weights and delay quantization in a long phased array. For reconfigurable digital beamforming (DBF), it is possible to store all the phasing samples and process them in real time. Therefore the quantization issue is different than digitizing a few phasing samples. Digital samples of phased signals are sensitive to finite precision. Finite precision reduces mainlobe level as well as sidelobe gain. For multiple beam generation, it degrades not only the transmitted beam but adjacent beams as well. The quantization effects depend on position of the quantizer. They are different when the quantizer is placed before and after beamforming network. Simulations have been performed to demonstrate the results.