A Millimeter-Wave Vortex Phase Imaging Method Developed for Lateral Resolution Enhancement

• Published in: IEEE antennas and wireless propagation letters 2024-01, Vol.23 (1), p.34-38
• Main Authors: Hu, Nairui, Qi, Feng, Wang, Yelong, Liu, Zhaoyang, Wang, Ningbo, Liu, Pengxiang, Li, Weifan
• Format: Article
• Language: English
• Subjects: Angular momentum; Electron beams; Focal plane; Horn antennas; Imaging; Millimeter wave radar; Millimeter waves; orbital angular momentum (OAM); Orbits; Phase plates; Sensors; Synthetic aperture radar; Three dimensional printing; vortex phase imaging; vortex spectrum; Wireless communication; Wireless sensor networks
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2023.3316136

In the present letter, a vortex phase imaging method is proposed to improve the lateral resolution of a millimeter-wave (MMW) focal plane imaging system. For the efficient transmission of vortex beams carrying different orbital angular momentum (OAM), the spiral phase plates processed by 3-D printing technology are designed to be loaded onto the front of horn antenna. Then, the reflection spectra of the object are analyzed for discussion. A specific OAM mode carrying more azimuth information is found to be dominant under a vortex incidence, and a sharper image can theoretically be obtained using the vortex phase. In addition, a concise reflective vortex imaging system is developed to collect the information about OAM phase. According to the experimental results, the vortex phase imaging method proposed in this study is effective in significantly improving the outcome of imaging at 80 GHz, with a lateral -resolution of 0.42 λ 0 achieved. This method is applicable to other MMW imaging systems, which may contribute to an in-depth understanding and utilization of scattering vortex spectrum.