基于模态复用的涡旋电磁波前视成像方法

A Mode-Multiplexed Orbital Angular Momentum-Based Forward-Looking Imaging Method

摘要: 前视成像技术在航空航天、雷达侦察和自动驾驶等领域具有重要应用价值。然而，传统前视成像由于缺乏方位多普勒频率信息，难以实现高分辨率成像。涡旋电磁波因其独特的轨道角动量(OAM)特性，在侧视合成孔径雷达(SAR)中得到了广泛应用。然而，其在前视成像中的应用研究仍较为匮乏。本文提出了一种基于模态复用的涡旋电磁波前视成像方法，通过复用正负OAM模态并结合希尔伯特变换，解决了传统前视成像中因频率混叠引起的伪点问题，显著提升了成像质量和效率。仿真结果表明，该方法在保持高分辨率的同时，将发射次数和照射时间均减少了一半，为涡旋电磁波在前视成像领域的实际应用提供了理论和技术支持。

Abstract: Forward-looking imaging technology plays a significant role in aerospace, radar reconnaissance, and autonomous driving. However, traditional forward-looking imaging methods struggle to achieve high-resolution imaging due to the lack of azimuthal Doppler frequency information, particularly under static observation conditions. Vortex electromagnetic waves, characterized by their unique orbital angular momentum (OAM) properties, have found extensive applications in side-looking synthetic aperture radar (SAR). Nevertheless, their application in forward-looking imaging remains underexplored. This paper proposes a forward-looking imaging method based on mode-multiplexed vortex electromagnetic waves. By leveraging both positive and negative OAM modes and combining them with Hilbert transforms, this method effectively addresses the issue of ghost points caused by frequency overlap in traditional forward-looking imaging. The proposed approach significantly enhances imaging quality and efficiency. Simulation results demonstrate that the method maintains high resolution while halving the number of transmissions and illumination time. This advancement provides theoretical and technical support for the practical application of vortex electromagnetic waves in forward-looking imaging.