SGER: Ultra Wideband Time-Variant Matching Networks with Very High Impedance Ratios for Nanoscale Electronics

目的：探索在超宽带（DC-9GHz）上实现非常高阻抗变换（200:1）的新型射频电路拓扑设计，而不是在频域。所提出的方法将导致电路将有助于通信和表征系统专注于高阻抗射频元件，包括纳米级场效应管和纳米机械谐振器。知识优势：半个多世纪以来，几乎所有无线商业通信系统的设计都遵循两个主要的设计惯例：1)由于技术限制，射频系统阻抗设置为50，可实现的阻抗转换比小于10:1；2)传输数据的带宽被限制在中心频率的一小部分，通常小于10%。虽然更高的带宽是可能的，但它们是以额外的损耗和芯片上的空间为代价的。直到最近，这些限制并没有阻碍高性能无线通信系统的实现，因为传统的射频设备和主要开发的频域设计技术非常适合50窄带系统。然而，纳米技术的出现使微波工程师能够制造出具有截然不同特性的射频器件，而这些特性往往与传统的设计规则相冲突。为了满足速度和频率的要求，有源（晶体管）和无源（纳米机械谐振器）射频器件的尺寸都在从微米缩小到纳米三个数量级，它们的阻抗越来越高，现在达到1-50k。此外，超宽带（UWB）架构最近才被FCC合法化，允许设计人员开发更简单的接收器架构。然而，实现低损耗和紧凑的超宽带匹配网络以及产生比5GHz宽脉冲的电子电路的实际困难，目前将该技术限制在较低的UWB频段（3.1 -4.8 GHz），留下了更有趣的频谱允许部分（5 -10.6 GHz）未被探索。在这些领域完全缺乏解决方案，使得纳米级器件集成到RF系统实际上是不可能的。探索性建议的工作重点是开发革命性的设计技术来缓解上述问题。特别是，我们建议探索在时间而不是频域设计的新型射频电路拓扑。这些拓扑是基于时变电路，可以重新配置和匹配所需的带宽。我们的初步结果清楚地表明，这些概念产生了极其简单和紧凑的电路，阻抗转换比超过200:1，带宽为9GHz。更广泛的影响：据研究人员所知，这是第一次尝试将时变电路用于宽带射频纳米电子学。这个领域特别有趣，因为它带来了显著更快的射频通信系统，并具有主要的成本和电池寿命优势。然而，由于它们的阻抗非常高，射频纳米电子学迄今尚未在任何系统架构中使用。它们与传统50系统（200:1到1000:1）之间的阻抗不匹配是如此之高，以至于这些设备无法使用。这项探索性研究首次为这一严重问题提出了可行的解决方案。如果成功，系统级研究人员将能够首次将射频纳米电子学的前景变为现实，因为他们将能够实现纳米放大器，混频器，滤波器以及最终的射频前端。

Objective: To explore novel RF circuit topologies designed in the time rather than in the frequency domain for achieving very high impedance transformations (200:1) over ultra wide bandwidths (DC-9GHz). The proposed approach will result in circuits that will be instrumental in communication and characterization systems focused on high-impedance RF components including nanoscale FETs and nanomechanical resonators.Intellectual Merit: For over half a century the design of nearly all wireless commercial communication systems has been following two major design conventions: 1) the RF system impedance is set to 50 with a realizable impedance transformation ratio of less than 10:1 due to technological limitations; 2) the bandwidth of the transmitted data is limited to a small fraction of the center frequency, typically less than 10%. Although higher bandwidths are possible, they come at the expense of extra loss and real estate on the chip. Until recently, these limitations have not hindered the implementation of high-performance wireless communication systems because conventional RF devices and the developed predominantly frequency-domain design techniques are well suited for 50 narrowband systems.The advent of nanotechnology, however, has enabled microwave engineers to produce RF devices with drastically different properties that often conflict with conventional design rules. As both active (transistors) and passive (nanomechanical resonators) RF devices are reducing in size by three orders of magnitude from micrometers to nanometers in order to satisfy speed and frequency requirements, their impedances are getting increasing higher and they now reach 1-50k. Moreover, ultra-wideband (UWB) architectures have been relatively recently legalized by the FCC allowing designers to develop significantly simpler receiver architectures. However, the practical difficulties of realizing low-loss and compact ultra-wideband matching networks as well as electronic circuits that produce pulses wider than 5GHz, is currently limiting this technology to the lower UWB band (3.1 -4.8 GHz), leaving the more interesting allowable part of the spectrum (5 -10.6 GHz) unexplored The complete lack of solutions in these areas has made the integration of nanoscale devices to RF systems practically impossible. The exploratory proposed effort is focused on developing revolutionary design techniques to alleviate the above described problems. In particular, we propose to explore novel RF circuit topologies designed in the time rather than in the frequency domain. These topologies are based on time-variant circuits that can be reconfigured and matched to the desired bandwidths. Our preliminary results clearly demonstrate that these concepts results in extremely simple and compact circuits with impedance transformation ratios in excess of 200:1 over a 9GHz bandwidth.Broader Impacts: To the best of the investigators' knowledge this is the first attempt to utilize time variant circuits for wideband RF nanoelectronics. This area is particularly interesting because it brings the promise of significantly faster RF communication systems with major cost and battery-life benefits. Due to their very high impedances, though, RF nanoelectronics have not been utilized in any system architectures so far. The impedance mismatch between them and traditional 50 systems (200:1 to 1000:1) is so high that renders these devices unusable. This exploratory research proposes for the first time a viable solution to this serious problem. If successful, system-level researchers will be capable for the first time to bring the promise of RF nanoelectronics to reality because they will be able to implement nano- amplifiers, mixers, filters and eventually RF front-ends.