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，可以以特定的几何图案部署，以检测给定频率范围内的无线电信号。使用阵列对电气工程是有益的，因为它可以放大无线电信号的方向，同时通过称为波束形成的过程抑制噪声和干扰。此外，天线阵列可以用来检测信号源的方向和距离。孔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，依靠孔径阵列为实验宇宙学和空间科学生成精确的电磁源射电图像。这些仪器使用被称为射电像素的紧密间隔的射电波束来成像天空。这种光束的紧密排列可以通过使用六边形像素网格来实现，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，必须开发有效的处理天线阵列信号的方案，以减少系统所需的计算时间、能耗和硬件成本。提出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无线电像素。同样的孔径阵列用于雷达和无线通信系统的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。除了其科学优点和国家安全效益外，该项目还将培养高素质人才（HQP），他们将为商业工业、科学研究、公共安全机构和国防部门做出贡献。具体的努力将集中在促进高等教育中的女性工程项目上，以招收和指导研究生和本科阶段的女性工程学生。本研究利用多维递归数字滤波器的数学特性，解决了高定向稀疏孔径阵列的问题。这项由美国国家科学基金会资助的研究将基于提出的网络谐振相控阵（nrpa）概念开发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，可以大大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。与具有相同灵敏度的传统相控阵接收机相比，使用较少的阵列元件，可以显著提高方向灵敏度。所提出的nrpa结合了网络共振的概念和相控阵技术，在方向性和灵敏度上都有了显著的提高。网络共振的MD电路理论概念允许数字波束形成器具有复杂的极流形。这些特性在超宽带频率响应、卓越的方向性、具有形状控制的多波束、快速转向性和低计算复杂度方面具有优势。该项目研究具有六角形天纹的无线电波束，以在宽视场和带宽上实现最佳传感和微波成像。提议的nrpa将通过降低硬件成本、减少计算机能耗和增加设计灵活性的理论公式扩展到稀疏和随机阵列。

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.