EFRI NewLAW: Novel Approaches to RF Non-Reciprocity in Semiconductor Systems

全球无线数据使用的爆炸式增长是过去十年中最大的经济驱动力之一，全球对廉价、高数据速率无线接入的需求预计将在至少另一个十年中继续快速增长。非互易组件，如循环器和隔离器，实现了新的无线通信范式，如全双工无线，否则是不可行的，并有望显著提高无线数据容量。然而，今天的非互易元件几乎完全是通过磁光法拉第效应实现的，需要使用铁氧体材料，这些材料昂贵、笨重，而且与推动无线和计算革命的硅基集成电路技术不兼容。该提案将设计，分析和实验证明基于时空调制的新的多物理场方法，该方法能够打破射频（RF）的互易性，并实现集成在商用硅基技术中的紧凑和低成本RF非互易组件。总的来说，这项研究将通过扩大可访问射频频谱的范围，实现更有效地共享现有频谱的新方案，减少非互易组件的尺寸和成本，使更大一部分人口可以访问无线设备，从而对增强无线数据访问的社会需求产生直接和关键的影响。在推广方面，该项目还将为从幼儿园到研究生院（K-12，本科和研究生）的学生提供教育和参与的机会，利用哥伦比亚大学和康奈尔大学的现有项目，与纽约自由科学中心合作，以及一些协调的推广和多元化项目。最近的研究表明，在材料或系统中引入时间差可以打破互惠。虽然时变非互易系统和组件没有基本的性能限制，但现有的用于实现非互易组件（如环行器）的时空调制方法在插入损耗、尺寸或线性方面充满了挑战。虽然传统的时空调制方法依赖于介电介质中介电常数的变化，但该提案的关键见解是半导体系统提供了另一种可以更有效调制的材料特性。即电导率。基于这一见解，该项目将追求各种多物理场方法，以实现硅基集成电路技术中的非磁性射频非互易。该项目将电子学、声学和光学集成在一起，将展示射频、毫米波和太赫兹频率下的高性能非互易环行器和隔离器。该项目还将从理论（即数学）和实验的角度研究支持拓扑保护的非互反传播模式的合成RF介质，并将其应用于新兴无线通信范例（如大规模相控阵和大规模多输入多输出（MIMO）系统）的非互反天线接口。

The explosion in wireless data usage across the world has been one of the great economic drivers of the last decade, and the global need for cheap, high-data-rate wireless access is expected to continue to grow rapidly for at least another decade. Non-reciprocal components, such as circulators and isolators, enable new wireless communication paradigms such as full-duplex wireless that are otherwise not feasible and promise to significantly enhance wireless data capacity. However, non-reciprocal components today are almost exclusively realized through the magneto-optic Faraday effect, requiring the use of ferrite materials that are expensive, bulky and incompatible with the silicon-based integrated circuit technologies that power the wireless and computing revolutions. This proposal will devise, analyze and experimentally demonstrate new multi-physics approaches based on spatio-temporal modulation that enable the breaking of reciprocity at radio frequencies (RF), and the realization of compact and low-cost RF non-reciprocal components integrated in commercial silicon-based technologies. Broadly, this research will have a direct and critical impact on the societal need for enhanced access to wireless data by expanding the range of accessible RF spectrum, enabling new schemes for more efficiently sharing existing spectrum, and reducing the size and cost of nonreciprocal components, making wireless devices accessible to a larger portion of the population. In terms of outreach, this project will also provide opportunities for the education and engagement of students across the educational continuum from kindergarten through graduate school (K-12, undergraduate and graduate), leveraging existing programs at Columbia and Cornell, in collaboration with the Liberty Science Center in NYC and a number of coordinated outreach and diversity programs.Recent research has revealed that introducing time variance into a material or system enables the breaking of reciprocity. While there are no fundamental performance limits associated with time-varying non-reciprocal systems and components, existing spatio-temporal modulation approaches for the realization of non-reciprocal components such as circulators have been fraught with challenges in insertion loss, size or linearity. While traditional spatio-temporal modulation approaches have relied on the variation of permittivity in dielectric media, the key insight in this proposal is the fact that semiconductor systems offer another material property that can be more powerfully modulated ? namely conductivity. Based on this insight, this project will pursue various multi-physics approaches to achieve non-magnetic RF non- reciprocity in silicon-based integrated circuit technologies. Blending electronics with acoustics and optics in an integrated setting, this project will demonstrate high-performance non-reciprocal circulators and isolators at RF, millimeter-wave and terahertz frequencies. This project will also investigate synthetic RF media supporting topologically protected non-reciprocal modes of propagation from both a theoretical (i.e. mathematical) and experimental perspective, with applications in non-reciprocal antenna interfaces for emerging wireless communication paradigms such as large-scaled phased arrays and massive Multiple-Input-Multiple-Output (MIMO) systems.