Novel continuously tunable and miniaturized passive "slow-wave" phase shifters with fast response time for millimeter wave applications based on a combined Liquid Crystal (LC) and Nanowire-filled Membrane (NaM) technology

基于液晶 (LC) 和纳米线填充薄膜 (NaM) 技术的新型连续可调小型无源“慢波”移相器，具有快速响应时间，适用于毫米波应用

• 批准号: 314460176
• 负责人: Professor Dr.-Ing. Rolf Jakoby
• 金额: --
• 依托单位: Universidade de São Paulo (USP)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/314460176?language=en
• 关键词: Novel; continuously; tunable; miniaturized; passive

Novel Liquid Crystal (LC) technology, which has been innovatively adapted beyond optics during last decade by TU Darmstadt, appears to be the most promising approach for tunable components at millimeter waves, since LC losses decrease with frequency. At 30 GHz, it features very low dielectric losses of tand < 0.006 and continuous tunability up to 27 %, resulting in a Figure-of-Merit (FoM) defined by the ratio of the maximum differential phase shift over the highest insertion loss in all tuning states of about 200°/dB or 110° /dB for hollow waveguide or microstrip line phase shifters, respectively. Although planar technologies own system-inherently higher losses than hollow-waveguide topologies, they are low-profile and can easily be realized, utilizing automated manufacturing techniques similar to well-established LCD technology. This enables a low-cost fabrication of larger arrays even for a low-volume production. Since LC is a dielectric, its power consumption for tuning is extremely low. However, LC phase shifters face two critical parameters: too large length for 360°-phase shift, much more than for the restricted space beneath the antenna elements, and too slow response time (typically > 1 min), where at least less than 30 ms is required for high beam-steering rate in mobile applications. To overcome these problems, the proposed project aims for a new technology, enabling to satisfy all the addressed requirements, i.e. high FoM, low insertion loss, fast response time, low-power consumption, high linearity, low-cost, reliability, light-weight, compact (miniaturized) and flat (low-profile), simultaneously, by merging for the first time worldwide two independently developed innovative technologies: Liquid Crystal (LC) and Nanowire-filled Membrane (NaM) Technologies. The combined LC-NaM technology enables in general tunable microwave devices such as phase shifters miniaturized by factor of at least three, utilizing the slow-wave effect. As a proof-of-concept of this new technology, tunable passive slow-wave microstrip line phase shifters will be designed, realized and investigated for the first time, exemplary for WPAN application at 60 GHz. The objective is to achieve effective LClayer thickness of few µm only between the top of the nanowires and signal electrode, thus, keeping high performances for the planar microstrip topology with FoM of at least 70°/dB at 60 GHz. At the same time, the device's response time will be reduced dramatically from more than 1 min down to 30 ms compared to conventional tunable LC-based microstrip lines with 50 to 150 µm distances between the biasing electrodes. Thus, with this technology, it is feasible to realize a new generation of miniaturized phase shifters, having a fast response time and high FoM at millimeter waves with very low power consumption, and which could easily be integrated into each antenna element of a large beam-steering antenna array.

新型液晶（LC）技术，在过去十年中由达姆施塔特工业大学创新地应用于光学之外，似乎是毫米波可调谐元件最有前途的方法，因为LC损耗随频率而降低。在30 GHz时，它具有非常低的介电损耗（小于0.006）和高达27%的连续可调谐性，从而产生由所有调谐状态下最大差分相移与最高插入损耗之比定义的性能图（FoM），中空波导或微带线移相器分别约为200°/dB或110°/dB。虽然平面技术本身具有比空心波导拓扑更高的系统损耗，但它们是低调的，可以很容易地实现，利用类似于成熟的LCD技术的自动化制造技术。这使得低成本制造更大的阵列，即使是小批量生产。由于LC是电介质，因此其调谐功耗极低。然而，LC移相器面临两个关键参数：对于360°相移来说，长度太大，远远超过天线元件下方的有限空间，并且响应时间太慢（通常为bbb10分钟），其中在移动应用中需要至少少于30毫秒的高波束转向率。为了克服这些问题，该项目旨在开发一种新技术，通过在全球范围内首次合并两种独立开发的创新技术：液晶（LC）和纳米线填充膜（NaM）技术，同时满足所有解决的要求，即高FoM、低插入损耗、快速响应时间、低功耗、高线性、低成本、可靠、轻量化、紧凑（小型化）和扁平（低轮廓）。结合LC-NaM技术，一般可调谐微波器件，如移相器小型化至少三倍，利用慢波效应。作为这项新技术的概念验证，将首次设计、实现和研究可调谐无源慢波微带线移相器，作为60ghz WPAN应用的范例。目标是实现仅在纳米线顶部和信号电极之间的有效l层厚度为几µm，从而保持60 GHz时FoM至少为70°/dB的平面微带拓扑的高性能。与此同时，与传统的可调谐lc微带线相比，该器件的响应时间将从超过1分钟减少到30毫秒，偏置电极之间的距离为50至150 μ m。因此，利用该技术，可以实现新一代小型化移相器，该移相器在毫米波下具有快速响应时间和高FoM，功耗极低，并且可以很容易地集成到大型波束转向天线阵列的每个天线元件中。

项目成果

Miniaturized Liquid Crystal Slow Wave Phase Shifter Based on Nanowire Filled Membranes

• DOI: 10.1109/lmwc.2018.2845938
• 发表时间: 2018-06
• 期刊: IEEE Microwave and Wireless Components Letters
• 影响因子: 3
• 作者: M. Jost;J. S. K. Gautam;L. Gomes;R. Reese;E. Polat;M. Nickel;J. M. Pinheiro;A. Serrano;H. Maune;G. Rehder;P. Ferrari;R. Jakoby