High Resolution 2-D Electromagnetic Vortex Imaging Using Uniform Circular Arrays

Abstract

The vortex electromagnetic (EM) wave carrying orbital angular momentum (OAM) has been introduced in radar imaging to take full advantage of its special phase front. It has been demonstrated that the azimuthal and range resolution are decided by the number of OAM mode and frequency bandwidth respectively. In this paper, theelevation resolution of the vortex wave transmitted by a uniform circular array is derived for the first time through the calculation of correlation function of two closely adjacent points. Since large number of OAM modes should be applied to achieve high-resolution image, which is difficult to realize in practice, the sparse Bayesian learning (SBL) is introduced to reconstruct the targets for 2-D EM vortex imaging. Simulation results show that the targets located at different elevation angle can be reconstructed correctly and higher resolution can be achieved based on the SBL reconstruction algorithm. INDEX TERMS Uniform circular array, orbital angular momentum, radar imaging, sparse Bayesian learning. ZI HE was born in Hebei, China. She received the B.Sc. and Ph.D. degrees in electronic information engineering from the School of Electrical Engineering and Optical Technique, Nanjing

Orbital Angular Momentum Beam Antenna Systems for Wireless Communications – A Brief Review

“…OAM beams in the literature, are shown to be capable of improving spectral efficiency for wireless communications by generating multiple sub-channels at different twisting degrees, and hence, has a strong potential for applications in future telecommunications [3]- [5]. With the introduction of OAM, an extra degree of freedom can be introduced within several sensing and imaging applications [6]- [9].…”

SAR Imaging Based on OAM‐ωK Algorithm

“…Afterward, many scholars have begun algorithms research on vortex EM waves imaging. To achieve vortex EM waves imaging, they designed various imaging scenarios (S. Guo et al., 2019; H. Liu et al., 2020; K. Liu et al., 2020; D. Liu et al., 2023; Y. Wang et al., 2022; Yuan et al., 2016; Zhou et al., 2022) and OAM modes (S. Guo et al., 2020; Li et al., 2022; H. Liu et al., 2021; J. Wang et al., 2019; Yang et al., 2022) based on radar imaging algorithms such as the Range Doppler algorithm (J. Wang et al., 2019), the ωK algorithm (Bu, Zhang, Chen, et al., 2018), the Chirp Scaling algorithm (Zhang et al., 2019, 2022), the back propagation algorithm (K. Liu, Cheng et al., 2018), and so on. Recently, some scholars have been able to verify the effectiveness of their improved algorithms through experiments, and they have also proven the feasibility of vortex EM waves in the field of radar imaging (Bu, Zhang, Chen, et al., 2018; Bu, Zhang, Liang, et al., 2018; K. Liu et al., 2017; H. Liu et al., 2020; J. E. Stopa et al., 2022; C. Zhang et al., 2019).…”

High‐resolution passive imaging by electromagnetic vortex beams

“…Multimode measurements are conducted during the scanning process to construct equations to solve the unknown bright temperature. Considering that the generation of high‐OAM modes is limited by the aperture size of the antenna, 12 compress sensing (CS) method is introduced to reduce the number of OAM mode. The rest of this article is organized as follows.…”