Collaborative Research: Electronically-Scanned Wideband Digital Aperture Antenna Arrays using Multi-Dimensional Space-Time Circuit-Network Resonance: Theory and Hardware

孔径阵列是一组天线，可以部署在特定的几何图案中，以检测给定频率范围的无线电信号。使用阵列对电气工程是有益的，因为它可以在信号方向上放大无线电信号，同时通过一种称为波束成形的过程来抑制噪声和干扰。此外，天线阵还可以用来检测信号源的方向和距离。口径阵列是测量射电源空间分布的科学仪器的重要组成部分。例如，射电望远镜，如平方公里阵列(SKA)仪器，依靠口径阵列为实验宇宙学和空间科学产生精确的电磁源射电图像。这些仪器使用被称为射电像素的密集射电波束对天空进行成像。这种光束的紧密排列可以通过使用六边形像素栅格来实现，这被认为是科学研究的理想选择。为了构建用于特定目的的孔径波束形成器，必须开发用于处理天线阵列信号的有效方案，以减少系统中所需的硬件的计算时间、能量消耗和成本。这项拟议的研究创造了新的算法和数字计算架构，将为最苛刻的微波成像应用产生高度聚焦的六角形射电像素。同样的孔径阵列被用于雷达和无线通信系统，用于特征检测和信号情报。事实上，从威胁检测的角度来看，孔径阵列对于国家安全和公共安全是绝对必要的。除了科学上的优点和对国家安全的好处外，这个项目还将培养高素质的人才，他们将为商业、科学研究、公共安全机构和国防部门做出贡献。具体工作将侧重于促进高等教育中的女性工程项目，招收和指导研究生和本科生中的女性工程学学生。提出的研究利用多维递归数字滤波器的数学特性来解决高方向性稀疏孔径阵列的问题。这项由美国国家科学基金会赞助的工作将基于拟议的网络谐振相控阵(NRPA)概念，开发用于孔径阵列的硬件系统。多维(MD)电路理论和数字硬件构成了成像算法的使能技术，可以极大地提高传统技术的性能。本研究提出了基于阵列信号处理、电路和系统的突破性技术。与相同灵敏度的传统相控阵接收机相比，它将在使用更少的阵元的同时显著提高方向灵敏度。所提出的NRPA将网络谐振的概念与相控阵技术相结合，在方向性和灵敏度方面都有了显着的改善。网络谐振的MD电路理论概念允许数字波束形成器具有复杂的极点流形。这些特性在超宽带频率响应、特殊的方向性、具有形状控制的多波束、快速可操纵性和低计算复杂性方面具有优势。该项目研究具有六角形天空图的射电波束，以便在大视场和带宽上进行最佳传感和微波成像。提出的NRPA将通过理论公式扩展到稀疏和随机阵列，以降低硬件成本、减少计算机能耗和增加设计灵活性。

An aperture array is a group of antennas that can be deployed in particular geometric patterns to detect radio signals at a given range of frequencies. Using an array is beneficial for electrical engineering because it can magnify a radio signal in the direction of that signal while suppressing noise and interference through a process known as beamforming. In addition, an antenna array can be used to detect the direction and distance of the signal's source. Aperture arrays are a crucial component of scientific instruments that measure the spatial distribution of radio sources. For example, radio telescopes, such as the Square Kilometer Array (SKA) instrument, rely on aperture arrays to generate precise radio images of electromagnetic sources for experimental cosmology and space science. These instruments image the sky using closely spaced radio beams known as radio pixels. Closely packed sets of such beams can be achieved by using hexagonal pixel grids, which are considered ideal for scientific studies. In order to build aperture beamformers to be used for a specific purpose, efficient schemes for processing the antenna array signals must be developed to reduce the computing time, energy consumption, and costs for the hardware required in the system. The proposed research creates new algorithms and digital computing architectures that will produce highly-focused hexagonal radio pixels for the most demanding of microwave imaging applications. The same aperture arrays are used in radar and wireless communication systems for signature detection and signal intelligence. In fact, aperture arrays are absolutely essential for national security and public safety from a threat detection perspective. In addition to its scientific merits and benefits for national security, this project will train highly qualified personnel (HQP), who will contribute to commercial industry, scientific research, public safety agencies, and the defense sector. Specific efforts will focus on promoting Women in Engineering programs in higher education to recruit and guide female engineering students at both the graduate and undergraduate levels. The proposed research tackles the problem of highly directional sparse aperture arrays using the mathematical properties of multi-dimensional recursive digital filters. The NSF-sponsored effort will develop hardware systems for aperture arrays based on the proposed concept of network-resonant phased-arrays (NRPAs). Multi-dimensional (MD) circuit theory and digital hardware form an enabling technology for imaging algorithms that can greatly improve performance over traditional technologies. This research proposes groundbreaking techniques based on array signal processing, circuits and systems. It will result in a significant improvement in the directional sensitivity while using a lower number of array elements compared to traditional phased array receivers of the same sensitivity. The proposed NRPAs combine the concept of network resonance with phased array technology to gain significant improvement in both directionality and sensitivity. The MD circuit theoretical concept of network resonance allows digital beamformers to have complex pole manifolds. These properties are shown to have advantages in terms of ultra-wideband frequency response, exceptional directionality, multi-beams with shape control, rapid steerability, and low computational complexity. This project investigates radio beams with a hexagonal sky-print for optimal sensing and microwave imaging over wide fields-of-view and bandwidths. The proposed NRPAs will be extended to both sparse and random arrays via theoretical formulations for decreasing hardware cost, reducing energy expended in computers and increasing design flexibility.