Suppression of grating lobes in stepped-frequency train

Abstract

For uniform frequency stepped pulse trains, there can be undesirable peaks of the autocorrelation function, known as "grating lobes". In this paper we address this issue, using an approach, which allows us to suppress grating lobes below a desired threshold level in the case of appropriately chosen, stepped frequency waveforms, i.e., sequences of narrowband pulses that span the desired bandwidth. We discuss in detail how to choose relevant parameters in order to produce such waveforms with small grating lobes, and give examples of waveforms with small overlap ratio. We also discuss the issue of high sidelobes in the vicinity of the main lobe, which are inevitable in a train of LFM waveforms, and show that it is possible to suppress these, as well as the grating lobes, by means of phase modulation.