基于模式分集的光纤真延时二维多波束形成技术研究

为满足雷达系统和无线通信系统在全空域实现多目标搜索和跟踪的实际需求，针对目前二维波束形成系统难以兼具广覆盖、低成本、多波束扫描的问题，本项目提出了一种基于模式分集的光纤真延时二维多波束形成技术，利用少模光纤的模式维度，在单一波长条件下实现广覆盖、低成本、多波束的二维波束形成系统。本课题拟研究少模光纤不同模式的延时调控技术，研究基于模式分集的光纤真延时二维多波束的形成和调控技术，解决模式耦合带来的波束旁瓣抬高和主极大峰功率下降问题，完成基于模式分集的光纤真延时二维多波束系统的原理性实验，主要技术指标为：方位角扫描范围≥±60度，俯仰角扫描范围≥±60度，波束数量≥4。基于模式分集的光纤真延时二维多波束形成技术在单一波长下就可以实现二维多波束的形成和调控，具有成本低、覆盖范围大、易于实现多波束扫描等特点。课题研究将为高性能波束形成提供一种新的思路和有效方法。

Radar systems and wireless communication systems are widely applied to search and track multiple targets in space. However, it is difficult for the two-dimensional beam forming system in terms of trading off wide coverage, low cost and multi-beam scanning at present. To meet the practical requirements of the radar systems and wireless communication systems, a fiber-optic true delay two-dimensional multi-beam forming technology based on mode diversity is proposed in this proposal. The two-dimensional beam forming system with wide coverage, low cost and multi-beam forming capability is realized by bringing in the modes of few-mode fiber under a single wavelength. In this project, we will study the delay steering technology of different modes of the few-mode fiber. The formation and steering technology of the fiber-optic true delay two-dimensional multi-beam former based on mode diversity will be researched. The problem of the beam side lobe elevation and the main peak power reduction caused by the mode coupling will be solved. The principle experiment of fiber-optic true delay two-dimensional multi-beam former based on mode diversity will be accomplished. The two-dimensional multi-beam former with main technical indicators are that azimuth scanning range will be equal or greater than ±60 degrees, elevation scanning range will be equal or greater than±60 degrees , the number of beams will be equal or greater than 4. The fiber-optic true delay two-dimensional multi-beam former based on mode diversity can be realized and steered under a single wavelength，which has the advantages of wide coverage, low cost and easy multi-beam scanning. Our project will provide some new ideas and effective methods for high-performance beam forming.