EAGER: A Technology Demonstrator for a mmWave Rapid Scan Image Phased Array Radar for Cloud Research

云在地球大气中发挥着至关重要的作用，它调节辐射平衡，影响降水模式和强度，并产生垂直的空气运动，重新分配热量、水分和动量。云过程的某些方面仍然知之甚少，部分原因是科学界缺乏云的高空间和时间分辨率测量。相控阵雷达可以在这方面提供帮助，因为这些雷达能够使用电子束转向快速扫描。相控阵雷达已经在国防领域使用了几十年，并且正在扩大在气象部门降水观测中的使用。然而，该技术尚未被用于毫米波地面云雷达。该合同将允许研究团队建造一个毫米波相控阵演示装置，该装置将检验未来陆基移动相控阵云雷达的可行性。该项目的下游影响将是为研究积云演变、云和降水过程以及龙卷风形成和风结构提供数据。学生和早期职业科学家将参与该装置的设计和测试，从而为下一代科学家和工程师提供实践培训。还将举行一个社区研讨会，以促进正在或可能正在使用云雷达进行研究的科学家之间的合作。该合同是为了开发一种毫米波长快速扫描雷达的技术演示单元。毫米波长雷达通常用于测量较小的颗粒，如云滴，而传统的气象雷达则测量降水大小的颗粒。虽然降水雷达采用了双偏振相控阵技术来快速扫描和检索粒子形状，但这些增强功能尚未在更短的波长上得到证实。根据EAGER合同，将产生一种具有新颖天线结构的8x8单元阵列，这将证明毫米波快速扫描成像相控阵雷达的可行性。所提出的阵列单元将具有优异的共极匹配波束方向图（0.1 dB）、高极化隔离（40 dB）和大扫描性能。无线测试技术将用于在接收模式下对相控阵天线中的每个有源元件进行表征和校准。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Clouds play a crucial role in the Earth’s atmosphere by regulating the radiative balance, influencing precipitation patterns and intensity, and generating vertical air movements that redistribute heat, moisture, and momentum. Some aspects of cloud processes remain poorly understood, partly because the scientific community has lacked high spatial and temporal resolution measurements of clouds. Phased-array radar can help in this area, as these radars are able to rapidly scan using electronic beam steering. Phased-array radar has been used for decades in the defense sector and is expanding in use in the weather sector for precipitation observations. However, the technology has not yet been adopted for use as a ground-based cloud radar at millimeter wavelengths. This award will allow the research team to build a millimeter wavelength phased array demonstrator unit, which will examine the feasibility of a future ground-based, mobile phased array cloud radar. The downstream impact of this project will be to provide data for studies of cumulus evolution, cloud and precipitation processes, and tornado formation and wind structure. Students and early-career scientists will be involved in the design and testing of the unit, thereby providing hands-on training for the next generation of scientists and engineers. A community workshop will also be held to foster collaboration between scientists that are, or could be, using cloud radars for their research.This award is for the development of a technology demonstrator unit cell for a millimeter-wavelength rapid scan radar. Millimeter-wavelength radars are generally designed for the measurement of smaller particles, such as cloud droplets, versus traditional weather radars which measure precipitation-sized particles. While precipitation radars have employed phased-array technology with dual-polarization to rapidly scan and retrieve particle shapes, these enhancements have not been demonstrated for shorter wavelengths. This EAGER award will result in an 8x8 element array unit with a novel antenna architecture that would demonstrate the feasibility of a millimeter wavelength rapid scan imaging phased array radar. The proposed array unit-cell will be designed to have excellent co-polar match beam pattern ( 0.1 dB), high polarization isolation ( 40 dB), and large scanning performance. An over-the-air testing technique will be used to characterize and calibrate each active element in the phased array antenna in reception mode.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.