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

目的：探索在超宽带(DC-9 GHz)上实现超高阻抗(200：1)变换的新型射频电路拓扑结构。智能优点：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，但这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施，因为传统的射频设备和开发的以频域为主的设计技术非常适合50个窄带系统。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的特性的射频设备，这往往与传统的设计规则相冲突。随着有源(晶体管)和无源(纳米机械谐振器)射频器件的尺寸从微米减小到纳米三个数量级，以满足速度和频率要求，它们的阻抗越来越高，现在达到1-50K。此外，超宽带(UWB)架构最近已被FCC合法化，允许设计者开发明显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5 GHz以上脉冲的电子电路的实际困难，目前正将这项技术限制在较低的UWB频段(3.1-4.8 GHz)，留下频谱中更有趣的允许部分(5-10.6 GHz)未被探索由于这些领域完全缺乏解决方案，使得纳米级设备几乎不可能集成到射频系统中。探索性的拟议工作集中于开发革命性的设计技术，以缓解上述问题。特别是，我们建议探索在时间域而不是在频域中设计的新型射频电路拓扑。这些拓扑基于可重新配置和匹配所需带宽的时变电路。我们的初步结果清楚地表明，这些概念导致了极其简单和紧凑的电路，在9 GHz的带宽上，阻抗变换比超过200：1。广泛的影响：据研究人员所知，这是首次尝试将时变电路用于宽带射频纳米电子设备。这一领域尤其令人感兴趣，因为它带来了极快的射频通信系统的前景，并带来了巨大的成本和电池寿命方面的好处。然而，由于其非常高的阻抗，到目前为止，射频纳米电子学还没有被用于任何系统架构中。它们与传统50系统(200：1到1000：1)之间的阻抗失配非常高，导致这些设备无法使用。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，系统级的研究人员将首次有能力将射频纳米电子学的前景变成现实，因为他们将能够实现纳米放大器、混频器、过滤器，并最终实现射频前端。

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.