Collaborative Research: Arrays, Analog RF 2-D Filters, and Nanostructured Multiferroic Antennas for MM-wave OAM-Multiplexed Wireless Systems

无线射频 (RF) 通信依赖于波的幅度和相位中的信息编码，这些波的模式类似于将石头扔进池塘时产生的同心圆波纹。 据说携带非零轨道角动量（OAM）的无线电波更像是水从水槽排出时形成的漩涡。 这些涡旋波的 OAM 特性为传输信息提供了额外的维度。这项研究将研究天线阵列模拟滤波方法，该方法可以在存在电磁干扰和噪声的情况下从接收信号中提取 OAM 信息。基于拓扑和多维信号处理的数学滤波器设计技术将使用基于互补金属氧化物半导体（CMOS）的递归滤波器来实现，从而实现高频、连续时间数据提取。 将创建电路理论，用于设计具有多 GHz 带宽的射频涡旋波阵列处理器，以应对微波和毫米波范围内具有挑战性的实现。这项工作提供了一种利用未使用的设计尺寸的新技术。 除了为通信工程师提供物理上实现 OAM 复用的新方法之外，这项工作的结果还可能为改进成像和加密技术提供改变范式的解决方案。这些技术可能会影响医疗、电信、国防工业以及射电天文学和大气科学。 这些知识将通过大会和会议的外展活动来传播。该项目包括一名女性 PI，并将涉及代表性不足的群体的参与。阿克伦大学和德克萨斯大学达拉斯分校将为高中女生举办夏季 STEM 讲习班。 实验室开放日将向公众介绍该项目对于未来无线系统的可能优点。尽管涡旋模式占用相同的载波频率和带宽，但它们彼此正交，从而允许独立的信息编码。 OAM 复用允许使用重叠的无线电带宽进行编码。该项目探索了使用阵列处理和模拟射频集成电路 (IC) 以电子方式调谐到所需涡流模式的阵列处理方案。提出了基于曲线多维信号处理的滤波器设计技术，用于使用递归滤波器的涡旋波阵列处理，从而实现高频连续时间 RF CMOS。 将创建电路理论，用于设计具有多 GHz 带宽的射频涡旋波阵列处理器，以应对微波和毫米波范围内具有挑战性的实现。模拟实现的设计方法和技术将来自涡流信号处理器的理论分析、电路综合、仿真和建模。为了解决传入信号的散射问题，该项目探索了新型亚波长天线，该天线因其体积小而最大限度地减少了无线电波反射，并且对天线材料的特性阻抗进行了设计，以实现与自由空间的阻抗匹配。这项工作将利用磁电多铁材料（将使用聚合物纳米复合材料实现）的交叉耦合电、磁和声特性来大幅增强电小型天线的性能。 电磁能和声能之间的转换是有利的，因为特定频率的信号将具有比无线电波短得多的声波波长。

Wireless radio frequency (RF) communication has relied on encoding information in the amplitudes and phases of waves that have patterns analogous to the concentric circular ripples produced by dropping a stone into a pond. Radio waves that are said to carry non-zero Orbital Angular Momentum (OAM) are more like the swirling vortices that develop as water drains from a sink. The OAM property of these vortex waves provides an additional dimension for transmitting information. This research will investigate antenna array analog filtering methods that can extract the OAM information from a received signal despite the presence of electromagnetic interference and noise. Mathematical filter design techniques, founded on topology and multi-dimensional signal processing, will be realized using complementary metal oxide semiconductor (CMOS) based recursive filters, which will enable high-frequency, continuous-time data extraction. Circuit theory will be created for use in designing RF vortex wave array processors that have multi-GHz bandwidth for challenging realizations in the microwave and millimeter-wave range. This work provides a new technique for exploiting an unused design dimension. Apart from providing communications engineers with a new means of physically realizing OAM-multiplexing, the results of this effort might offer paradigm-changing solutions for improving imaging and encryption technologies. Such technologies could impact medical, telecommunications, and defense industries as well as radio astronomy and atmospheric science. This knowledge will be distributed through outreach activitie at conferences and meetings. The project includes a female PI and will involve participation from underrepresented groups. There will be summer STEM workshops for high-school girls at both the University of Akron and the University of Texas at Dallas. Lab open houses will educate the public of the possible merits of this project for future wireless systems.Vortex modes are orthogonal to each other despite occupying the same carrier frequency and bandwidth, allowing independent encoding of information. OAM-multiplexing allows encoding with overlapped radio bandwidth. The project explores array-processing schemes for electronically tuning onto desired vortex modes using array processing and analog RF integrated circuits (ICs). Filter design techniques founded on curvilinear multi-dimensional signal processing are proposed for vortex-wave array processing using recursive filters, leading to high frequency continuous-time RF CMOS realizations. Circuit theory will be created for use in designing RF vortex wave array processors that have multi-GHz bandwidth for challenging realizations in the microwave and millimeter-wave range. Design methodologies and techniques for analog realizations will result from theoretical analysis, circuit synthesis, simulation and modeling of the vortex signal processors. To circumvent the problem of scattering of incoming signals, the project explores novel subwavelength antennas that minimize radio wave reflections by virtue of their smallness and the fact that the characteristic impedance of the antenna material will be engineered so as to achieve impedance matching with free space. This work will take advantage of the cross-coupled electric, magnetic and acoustic properties of magnetoelectric multiferroic materials (to be realized using polymer nanocomposites) to drastically enhance the performance of electrically small antennas. Conversion between electromagnetic and acoustic energy is advantageous because a signal of a particular frequency will have a much shorter acoustic wavelength than that of a radio wave.