CAREER: Scalable Traveling and Standing Wave Structures for High Power and High Efficiency Terahertz and mm-Wave Radiator and Phased Array Systems

用于高功率和高效率太赫兹和毫米波辐射器和相控阵系统的可扩展行波和驻波结构正如摩尔定律预测的那样，半导体的规模已经持续了近半个世纪。它已经成为低成本、高效和高速电子产品的来源，可用于各种应用。然而，由于几个限制，这一趋势将在未来几年放缓甚至停止。这对于高速和高功率电子产品来说尤其重要，因为它们由于技术限制而变得极具挑战性。例如，众所周知，毫米波(毫米波)和太赫兹(THz)系统在健康、安全和工业中具有独特和重要的应用。隐蔽武器的检测、癌症诊断、高分辨率雷达、医学成像、3D成像和半导体晶片/设备检测，以及用于药物检测、食品质量控制和用于疾病诊断的呼气分析的生物/分子光谱，都是这些应用的许多例子。特别是，遥感、主动/被动成像和短程通信正在不断快速地向毫米波和太赫兹频率发展，以实现更高的分辨率和更高的数据速率。然而，今天，太赫兹系统是使用昂贵而笨重的设备实现的，例如气体激光器和离散的笨重组件。如果紧凑型和片上太赫兹系统实现，众多相关应用将迅速蓬勃发展，从而为高科技市场和研究和教学机构带来新的机遇。今天的固态技术，包括硅和化合物半导体，大麦可以覆盖太赫兹波段的较低部分，具有有用的辐射功率。此外，相控阵在其中一些应用中是必不可少的，以提高和定位辐射功率。移相器在传统的相控阵系统中是至关重要的，但在高频下，移相器的损耗非常大。在相控阵系统中集成这些移相器和稳定的信号的复杂性阻碍了设计者在芯片上实现THz大功率发射机。为了克服这些问题，PI从根本上引入了新的方法来设计太赫兹和毫米波频率下的谐波压控振荡器(VCO)、辐射器阵列和相控阵系统。PI的研究计划是利用这些方法使固态电子成为高性能片上THz系统的默认平台，这在今天是很难想象的。首先，PI引入了基于行波和驻波的独特特性的新型阵列结构，能够高效和高功率地产生和辐射信号。这些结构的重要特性如下：1-它们极大地简化了阵列的结构并导致高辐射功率和高DC-RF效率；2-除了属于振荡器结构的那些外，不需要额外的全局或局部布线，从而使得该结构固有地可扩展到用于辐射器和相控阵两者的更大的阵列尺寸；3-当用于相控阵时，它们完全消除了对结构中任何地方的移相器的需要；以及4-仅需要一个高频分频器来感测基频并将整个阵列锁定在频率合成器中，从而导致低功率操作。接下来，PI使用了“最佳信号条件”方法，并引入了一种新的技术来整形晶体管信号并提高振荡器中的谐波功率。PI将可扩展的阵列结构与信号整形技术相结合，提出了具有比现有技术水平高得多的性能的VCO、辐射器阵列和相控阵。PI相信，拟议的辐射体和相控阵将成为未来用于太赫兹和毫米波频率的雷达、传感器和通信应用的相控阵系统的基石。

Scalable Traveling and Standing Wave Structures for High Power and High Efficiency Terahertz and mm-Wave Radiator and Phased Array SystemsSemiconductor scaling has continued for almost half a century, as Moore's law predicted. It has been the source of low-cost, efficient, and high-speed electronics for numerous applications. This trend, however, is about to slow down or even stop in the next few years due to several limitations. This is particularly consequential for high-speed and high-power electronics as they become extremely challenging to implement due to the technology limitations. For example, millimeter wave (mm-wave) and terahertz (THz) systems are known to have unique and significant applications in health, security and industry. Detection of concealed weapons, cancer diagnosis, high-resolution radar, medical imaging, 3D imaging, and semiconductor wafer/device inspection, along with bio/molecular spectroscopy for drug detection, food quality control, and breath analyses for disease diagnosis are among many examples of these applications. In particular remote sensing, active/passive imaging and short-range communication are continually evolving at a rapid pace toward mm-wave and THz frequencies in order to achieve superior resolution and higher data rate. Today, however, THz systems are realized using expensive and bulky devices such as gas lasers and discrete bulky components. If compact and on-chip THz systems are realized the numerous related applications will rapidly flourish, resulting in new opportunities in high-tech marketplace and research and teaching institutions. Today's solid-state technologies including silicon and compound semiconductors can barley cover the lower part of the THz band with useful amount of radiated power. Moreover, phased arrays are essential in some of these applications to boost and localize the radiated power. Phase shifters are critical in a conventional phased array system but they are extremely lossy at high frequencies. The complications of integrating these phase shifters and a stable signal in phased array systems have prevented designers to implement THz high power transmitters on chip. To overcome these problems the PI introduces fundamentally new approaches to design harmonic voltage-controlled oscillators (VCO), radiator array and phased array systems at THz and mm-wave frequencies. The PI's research plan is to use these approaches to make solid-state electronics the default platform for high-performance on-chip THz systems, which are hard to envision today.First the PI introduces novel array structures based on the unique properties of traveling and standing waves that enable efficient and high power signal generation and radiation. The important properties of these structures are as follows: 1- they greatly simplify the structure of the array and result in high radiated power and high DC to RF efficiency, 2- no additional global or local routing is needed other than the ones that belong to the oscillator structure, thereby making this architecture inherently scalable to larger array sizes for both the radiator and the phased array, 3- when used in the phased array they completely eliminate the need of phase shifters anywhere in the structure, and 4- only one high frequency divider is needed to sense the fundamental frequency and lock the whole array in a frequency synthesizer, resulting in a low power operation. Next, the PI uses the "Optimum Signal Condition" methodology and introduces a new technique to shape the transistor signals and boost the harmonic power in oscillators. Combining the scalable array structures with the signal shaping technique the PI proposes VCOs, radiator arrays and phased arrays that have significantly higher performances than the state of the art. The PI believes the proposed radiator and phased array would be the cornerstone of future phased array systems for radar, sensor and communication applications at THz and mm-wave frequencies.