Electromagnetic Vortex-Based Radar Imaging Using a Single Receiving Antenna: Theory and Experimental Results

Abstract

Radar imaging based on electromagnetic vortex can achieve azimuth resolution without relative motion. The present paper investigates this imaging technique with the use of a single receiving antenna through theoretical analysis and experimental results. Compared with the use of multiple receiving antennas, the echoes from a single receiver cannot be used directly for image reconstruction using Fourier method. The reason is revealed by using the point spread function. An additional phase is compensated for each mode before imaging process based on the array parameters and the elevation of the targets. A proof-of-concept imaging system based on a circular phased array is created, and imaging experiments of corner-reflector targets are performed in an anechoic chamber. The azimuthal image is reconstructed by the use of Fourier transform and spectral estimation methods. The azimuth resolution of the two methods is analyzed and compared through experimental data. The experimental results verify the principle of azimuth resolution and the proposed phase compensation method.

Reflection, Transmission, and Absorption of Vortex Beams Propagation in an Inhomogeneous Magnetized Plasma Slab

“…According to the definition of expansion of spiral spectrum [38] . Then the weight of each OAM state is defined by the following (17):…”

“…After substituting (7) and (8) into (16) and (17), the OAM weights of the reflected and transmitted field components are plotted as shown in Figs.5-8.…”

“…Since then, the methods of generation of vortex beams in microwave and radio bands have been reported extensively in the literature [8]- [11]. Besides, the characteristics and applications of vortex microwave and radio beams, particularly in wireless communication [12]- [15] and radar target imaging [16], [17], have been the focus of attention. This is due to the fact that vortex beams can potentially increase the system capacity and spectral efficiency of wireless communication [12], and also have the potential to acquire the cross-range profile of the target [16].…”

An Inner- and Outer-Fed Dual-Arm Archimedean Spiral Antenna for Generating Multiple Orbital Angular Momentum Modes

“…Theoretically, the OAM vortex beam has infinite different OAM states, which are mutually orthogonal. Therefore, OAM holds promise to provide significant advances in high-capacity optical communications [7,8] and in improving imaging resolution [9].…”

Performance Analyses of the Radio Orbital Angular Momentum Steering Technique Based on Ka-Band Antenna

“…The application of radio OAM in radar regime [18,19] also becomes a hot topic. Target detection model based on OAM was proposed in [20], which employed a UCA to produce twisted beams to illuminate objects in the far field, providing a new perspective to estimate azimuth information of targets without any relative moves or beams scanning required by traditional radars.…”