Wave Amplitude and Phase Manipulable Microwave Transmission Line

目前，高频电路中最流行的传输线类型包括微带线、共面波导和带状线。低成本和低调的外形因素使它们多年来很受欢迎。尽管它们的损耗相对较低，但其不可操控的色散特性不允许太多的设计自由度。由于这些原因，在许多情况下，传统的时延正成为利用可用频谱、增强系统功能以及缩小微波电路和系统尺寸的主要瓶颈。超材料传输线(MTL)概念在21世纪初首次引入，在控制电磁波(EM)波的相位以及使电路和系统尺寸小型化方面提供了改进的控制。特别是，MTL的色散工程特性使微波电路设计技术发生了革命性的变化，产生了许多新的元件和系统。然而，不可忽略的损失和无法控制波的幅度一直是MTL的主要弱点，阻碍了技术转移到实际应用中。这项研究将建立一套新的理论，使电磁波的幅度和相位的控制，以改变下一代TL技术。这种新的传输线类别，即有源MTL，最终可能成为最通用的传输线解决方案，以帮助缓解对增强的数据容量、更高的空间分辨率、多功能以及更小的电路和系统尺寸的日益增长的技术需求。这项工作有可能在微波工程领域开辟新的领域，并将许多未来的应用转化为现实，例如汽车防撞雷达的自适应波束形成天线。该项目的教育和推广计划侧重于鼓励来自行业的专业人员参与超材料研究活动，并领导向行业的技术转移。此外，还将与当地行业和博物馆合作举办一系列研讨会，以推广超材料技术和STEM领域。这项提议的目的是建立新的理论基础，揭示有源MTL的潜力和局限性，并增强高频电磁波的传输特性和可重构性。为了确定新的有源MTL结构的原理并评估其可行性，将采用基于晶体管的负阻元件来补偿作为MTL基本组件的有损并联电感的损耗，特别是对于复合右手/左手(CRLH)传输线。这种方法对通过MTL传播的波的干扰最小，因此可以保留所有所需的超材料特性。提出的晶体管负阻CRLH型输电线路的理论研究和论证将是第一次尝试。如果成功，建议的MTL将提供对辐射波和导波的前所未有的控制，并克服困扰MTL十多年的固有损耗和不可重构性问题。项目成果将带来超材料技术的重大科学飞跃，为未来基于MTL的设备和系统建立新技术的原则和可行性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Currently, the most popular types of transmission lines (TLs) in high-frequency circuits include microstrip lines, coplanar waveguides, and striplines. Low cost and low-profile form factors have made them popular over the years. Although they are relatively low-loss, their non-manipulable dispersion properties do not allow much design freedom. For these reasons, in many situations, the conventional TLs are becoming a major bottleneck of utilizing available spectrum, enhancing system functionalities, and size reduction of the microwave circuits and systems. The metamaterial transmission line (MTL) concept, first introduced in the early 21st century, delivers improved control in manipulating the phase of the electromagnetic (EM) wave and in miniaturizing the circuit and system dimensions. In particular, the dispersion engineering feature of MTL has revolutionized microwave circuit design techniques and produced numerous novel components and systems. However, the non-negligible loss and inability to control the amplitude of the wave have been the MTL's main weakness, preventing the technology transfer to practical real-world applications. This research will establish a new set of theories that enable the control of the EM wave amplitude and phase to transform the next-generation TL technology. This new category of transmission lines, the active MTLs, may eventually serve as the most versatile transmission line solution to help alleviate ever increasing technological demand for enhanced data capacity, higher spatial resolution, multi-functionalities, and smaller circuit and system dimensions. This work has the potential to open new horizons in the field of microwave engineering and to bridge many future applications into reality, e.g., adaptable beam forming antennas for automotive collision avoidance radars. The educational and outreach plan of this project focuses on encouraging professionals from industry to participate in metamaterial research activities and lead the technology transfer to the industry. In addition, seminar series will be organized in collaboration with local industries and museums to promote metamaterial technology and the STEM fields in general. The objective of this proposal is to establish new theoretical foundations that will reveal the potentials and limitations of active MTLs and enhance the transmission characteristics and reconfigurability of high-frequency EM waves. To establish the principles and evaluate the feasibility of the new active MTL structure, transistor-based negative resistance elements will be incorporated to compensate the loss of lossy shunt inductors which are elemental components of MTL, in particular for composite right/left-handed (CRLH) transmission lines. This approach minimally interferes with the wave propagating through the MTL, thus can retain all desired metamaterial characteristics. The fundamental research and demonstration of the proposed transistor-based negative-resistance CRLH transmission line will be the first to be attempted. If successful, the proposed MTL will provide unprecedented control of both radiated waves and guided waves and overcome the inherent loss and non-reconfigurability problems that have plagued MTLs for over a decade. The project outcome will provide a significant scientific leap in metamaterial technology, establishing the principles and the feasibility of new technologies for future MTL-based devices and systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.