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

无线射频（RF）通信依赖于波的振幅和相位中的编码信息，这些波的模式类似于将石头扔进池塘所产生的同心圆形涟漪。据说携带非零轨道角动量（OAM）的无线电波更像是水从水槽中流出时形成的漩涡。涡旋波的OAM特性为传递信息提供了额外的维度。本研究将探讨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。数学滤波器设计技术，建立在拓扑和多维信号处理，将实现使用互补金属氧化物半导体（CMOS）为基础的递归滤波器，这将使高频，连续时间的数据提取。电路理论将用于设计具有多ghz带宽的射频涡流波阵列处理器，以在微波和毫米波范围内实现具有挑战性的实现。这项工作为开发未使用的设计维度提供了一种新技术。除了为通信工程师提供一种物理实现oam多路复用的新方法外，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。这些技术可以影响医疗、电信、国防工业以及射电天文学和大气科学。这些知识将通过各种会议的外联活动加以传播。该项目包括一名女性PI，并将涉及代表性不足群体的参与。阿克伦大学（University of Akron）和德克萨斯大学达拉斯分校（University of Texas at Dallas）将为高中女生举办夏季STEM研讨会。实验室开放日将教育公众这个项目对未来无线系统的可能优点。涡旋模式彼此正交，尽管占用相同的载波频率和带宽，允许独立编码的信息。oam复用允许用重叠的无线电带宽进行编码。该项目探索阵列处理方案，利用阵列处理和模拟射频集成电路（ic）将电子调谐到所需的涡流模式。提出了基于曲线多维信号处理的滤波器设计技术，利用递归滤波器对涡流波阵列进行处理，从而实现高频连续时间射频CMOS。电路理论将用于设计具有多ghz带宽的射频涡流波阵列处理器，以在微波和毫米波范围内实现具有挑战性的实现。模拟实现的设计方法和技术将来自旋涡信号处理器的理论分析、电路合成、仿真和建模。为了避免传入信号的散射问题，该项目探索新型亚波长天线，通过其体积小和天线材料的特性阻抗设计，使无线电波反射最小化，从而实现与自由空间的阻抗匹配。这项工作将利用磁电多铁性材料的交叉耦合电、磁和声学特性（将使用聚合物纳米复合材料实现）来大幅提高电小型天线的性能。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.