Time‐variant focusing range‐angle dependent beampattern synthesis by uniform circular frequency diverse array radar

• Main Authors: Zeeshan Ahmad, Zhiguo Shi, Chengwei Zhou
• Format: Article
• Language: English
• Published: Wiley 2021-01-01
• Series: IET Radar, Sonar & Navigation
• Online Access: https://doi.org/10.1049/rsn2.12014
• ISSN: 1751-8784; 1751-8792

Abstract The beam steering of phased array (PA) radar is fixed in one direction for all the ranges, thus the resulting beampattern is angle‐dependent but range‐independent. Compared with the PA radar, the frequency diverse array (FDA) radar can achieve range‐angle dependent beampattern by employing a small frequency increment across the array elements. Numerous studies have been conducted using linear FDAs, while other array configurations are seldom studied. On the other hand, the range‐angle dependent beampattern generated by the FDA is also time‐variant. However, previous studies on time‐invariant spatial‐focusing FDA beampatterns neglected the propagation process of the transmitted signals, leading the focused beampattern difficult to achieve when the transmit delay caused by wave propagation is considered. Taking the time‐variant property of the FDA beampatterns into consideration, in this study, we propose a novel uniform circular FDA (UC‐FDA) radar for short‐range beampattern synthesis. The UC‐FDA radar has the ability to scan azimuthally through 360°, which is a potential solution for applications requiring three‐dimensional beam steering. Furthermore, the proposed UC‐FDA radar adopts a pulse‐dependent non‐linear frequency offsets based on logistic map, together with multi‐carrier technique to achieve a dot‐shaped time‐variant focusing beampattern with minimum sidelobe levels and high‐resolution. The effectiveness of the proposed UC‐FDA radar is validated with simulated experiments.