Frequency Diverse Array Radar: New Results and Discrete Fourier Transform Based Beampattern

Abstract

In the phased-array radar signals from each antenna are transmitted at the same carrier frequency, which yields narrowly focused only angle dependent beampattern. In contrast, in the frequency-diverse-array (FDA) radar signals from antenna array are generally transmitted at linearly increasing frequencies that yields range, time, and angle dependent beampattern. Reported literature on FDA radar missed the contribution of path-differences in the signal model due to the antenna array elements, which may lead to misleading results. In this work, incorporating missed path-differences, the signal model of FDA radar is reanalyzed for reliable results. Moreover, a novel low complexity algorithm based on discrete-Fourier-transform (DFT) is proposed for the desired beampattern. In contrast to the standard FDA radar's \enquote{S} shaped beampattern, the beampattern of the proposed algorithm changes linearly with range and time. Furthermore, spatial exploration of FDA radar is derived and it is found that it depends on the frequency-offset and pulse-duration. Finally, the bound on the product of frequency offset and pulse duration is derived. Simulation results compare the performance of our proposed algorithm with the existing ones and show the superiority of our proposed algorithm.