Journal Article

Near-Field Target Detection Method for Vortex Electromagnetic Wave Radar based on Modal Baseline

Sun, Jiayue, Fu, Chaowei, Zheng, Chengxin, Liu, Junhao, Chen, Qian

2024

Overview

Vortex electromagnetic (EM) waves can provide more target information, which is orbital angular momentum (OAM), than traditional plane waves in the field of radar detection. By emitting multiple different OAM modes of vortex EM waves to the same target, the azimuth information of the target can be obtained. The Linear Frequency Modulated (LFM) radar is often used in current OAM radar design. At present, researches on vortex EM wave imaging usually requires the emission of a large number of OAM modes to irradiate the target. Although many achievements have been made to significantly reduce this number, it is often accompanied by problems such as loss of azimuth imaging accuracy or poor real-time performance in practical applications. In response to this issue, this paper proposes a near-field target detection method based on modal baseline using vortex EM waves. By alternately emitting vortex EM waves with least OAM mode difference of 1, the method achieves range-velocity imaging while the OAM mode phase information is not blurred. The target detection task is carried out in the range-Doppler dimension, avoiding the problem of azimuth imaging. Through signal processing, our method achieves 3d point cloud detection of target velocity, range, and azimuth. Simulation results compared with traditional phase comparison azimuth measurement method proved the superiority of our method. The work and results provide suggestions to the development of vortex EM wave target detection.

• Publisher: IOP Publishing
• Subject: Angular momentum / Azimuth / Electromagnetic radiation / Frequency modulation / Measurement methods / Near fields / Phase comparison / Plane waves / Radar detection / Radar imaging / Real time / Target detection / Vortices