Van Atta Array Reflector

AbstractRetrodirective arrays have attracted a lot of research interest due to their unique characteristic of automatically responding to an interrogator without any prior information on the source location. As a unique member in the family of retrodirective arrays, the Van Atta array reflectors have features of simple structure and low cost and hold great potential for use in military and commercial applications, such as mobile communication, vehicle radar, radio‐frequency identification (RFID), and wireless power transfer (WPT). The Van Atta arrays are composed of an even number of radiation elements connected by transmission lines with equal electrical lengths. This article provides a detailed overview of the most recent research on the Van Atta array reflectors. Firstly, the development of the Van Atta arrays is briefly reviewed, and the basic design ideas are introduced. Then, the detailed operation principle of the Van Atta arrays is described, together with the theoretical analysis and experimental measurement to obtain the scattering field patterns in both monostatic and bistatic cases. After that, the latest research progress including the designs of one‐ and two‐dimensional Van Atta arrays is discussed. Besides the passive reflectors, the active Van Atta arrays can be implemented by introducing amplifiers or modulation circuits. In addition, this article also presents a short review of some typical applications of the Van Atta arrays, including the fields of vehicle‐mounting reflectors associated with the intelligent transportation systems (ITSs), the wireless charging of electronic devices, and ultralong‐range chipless sensing. Some examples of transponders using the Van Atta structures for these applications are introduced. Finally, some challenges and future research directions for Van Atta reflectors are presented.