CAREER: Spectrally-Encoded Ultrafast Microwave Panoramic Camera

目前采用传统波束扫描技术的微波雷达系统不能同时获得全景视场和高扫描速度。这是由于机械转子或电子移相器的固有硬件延迟，或数字信号处理的计算时间过长造成的。这些限制可以通过将成像概念从光学转换到微波来从根本上克服，从而实现微波全景相机(MPC)。对这种集成的了解和理解将导致一种可用于广泛传感应用的新型雷达和成像传感器。拟议的MPC将特别应用于汽车雷达，以提供驾驶员辅助，使驾驶更加安全和方便。基于MPC的雷达实现的快速传感速度和全景视野将为司机提供潜在碰撞的早期预警。此外，MPC的超快帧速率将允许通过检测它们的多普勒特征来区分对象。有了全景视野，MPC还可以用于需要持续监控道路情况的自动驾驶系统。拟议工作的教育部分将通过让底特律大都会地区的社区大学生参与进来，将先进的汽车技术整合到本科教育中。它将通过密歇根州国王-查韦斯-公园(KCP)倡议的大学绑定计划进行。将鼓励社区大学生，特别是那些来自代表人数不足的群体的学生，参与天线和微波工程方面的研究活动，这些研究活动对当今的汽车雷达成像传感器和远程信息处理至关重要。这项研究的目的是将光谱编码共焦显微镜，一种基于光纤的高速扫描光学成像方法，转变为微波和毫米波状态。这种集成将使所提出的微波全景相机具有超快的扫描速度和全景视野。这种技术方法依赖于基于传输线的微波超材料的创造，也称为复合右手/左手传输线。通过定制微波异质材料形成频率扫描阵列，可以实现二维频率到空间的映射机制。利用二维角度映射方案以及从反射信号获得的距离信息将产生场景的三维图像。这项研究将展示以1 MHz的帧速率捕获180度方位角和仰角的三维微波图像的能力。快速的帧刷新率将允许捕获和利用移动对象的任何多普勒和微多普勒效应，以用于目标识别和识别。此外，通过工程微波超材料的色散特性，所提出的MPC可以设计成工作在多个频段，从而可以执行雷达系统的双频段操作，例如24 GHz和77 GHz的汽车雷达传感器。

Current microwave radar systems using conventional beam scanning techniques cannot simultaneously achieve a panoramic field of view (FOV) and high scanning speed. This is due to intrinsic hardware latencies from mechanical rotors or electronic phase shifters, or excessive computation time from digital signal processing. These limitations can fundamentally be overcome by transforming imaging concepts from optics into microwaves, enabling a microwave panoramic camera (MPC). The knowledge and understanding of such integration will lead to a novel category of radars and imaging sensors that can be used for a wide range of sensing applications. The proposed MPC will be applied, in particular, to automotive radar to provide driver assistance, making driving safer and more convenient. The fast sensing speed and panoramic FOV enabled by MPC-based radars will provide early warning of potential collisions to drivers. Furthermore, the ultrafast frame rate of MPCs will allow differentiation of objects by detecting their Doppler signatures. With a panoramic FOV, MPCs can also be used in autonomous driving systems requiring constant monitoring of road situations. The educational component of the proposed work will integrate advanced automotive technologies into undergraduate education by engaging community college students in the Metro Detroit area. It will be conducted through the University Bound Program, a State of Michigan King-Chavez-Parks (KCP) Initiative. Community college students, especially those from underrepresented groups, will be encouraged to participate in research activities in antenna and microwave engineering essential for today's automotive radar imaging sensors and telematics. The objective of this research is to transform spectrally encoded confocal microscopy, a fiber-based optical imaging method for high-speed scanning, into the microwave and millimeter-wave regime. This integration will enable the proposed microwave panoramic camera with ultrafast scanning speed and a panoramic field of view. The technical approach relies on the creation of transmission-line based microwave metamaterials, also known as composite right/left-handed transmission lines. By tailoring microwave metamaterials to form a frequency scanned array, a two-dimensional frequency-to-space mapping mechanism can be realized. Utilizing the two-dimensional angular mapping scheme along with the range information obtained from the reflected signal will result in an image of the scene in three dimensions. This research will demonstrate the capability to capture a three-dimensional microwave image with 180-degree FOV in both azimuth and elevation, with a frame-rate speed of 1 MHz. The fast frame refresh rate will allow any Doppler and micro-Doppler effects of moving objects to be captured and exploited for target recognition and identification. Furthermore, by engineering the dispersion characteristics of microwave metamaterials, the proposed MPC can be designed to work in multiple bands, making it feasible to perform dual-band operations for radar systems, such as 24 GHz and 77 GHz automotive radar sensors.