Radar is an acronym for "radio detection and ranging." However, the functions of today's radar systems, both in civilian and military applications, go beyond simple target detection and localization; they extend to tracking, imaging, classification, and more and involve different types of radar systems, such as through-the-wall , ground-penetration , automotive , and weather . ... [Show full abstract] Although radar technology has been well established for decades, a new line of compressed radars has recently emerged. These aim at reducing the complexity of classic radar systems by exploiting inherent prior information on the structure of the received signal from the targets. The goal of this article is to review these novel sub-Nyquist radars and their potential applications.