Tunable Gradient Index Fishnet Structures based on Liquid Crystals for Beam Steering Applications

用于光束转向应用的基于液晶的可调梯度折射率鱼网结构

• 批准号: 230900032
• 负责人: Professor Dr.-Ing. Christian Damm
• 金额: --
• 依托单位: Institut für Mikrowellentechnik (MWT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/230900032?language=en
• 关键词: Tunable; Gradient; Index; Fishnet; Structures

The objective of this project proposal is the design and investigation of a tunable gradient index fishnet structure based on liquid crystal (LC) for the application as transmit array for beam steering applications. It aims for the first time application of a fishnet structure with a non-uniform tuning voltage distribution transversal to the propagation direction of the incident beam. The tuning of the gradient will be realized by applying liquid crystals as voltage tunable dielectric. That way, the dispersion characteristics of the fishnet structure can be tuned in order to realize a steering of a transmitted beam. As the fishnet structure is excited in broadside direction the technological challenges for the fabrication are relatively small and well established LC technology as used for the fabrication of tunable planar microwave components can be applied. It has been shown that the fishnet structure can be applied up to the optical region. Together with the continuously tunable LC applications up to the THz region are possible.The project consists of two parts: the design and investigation of a tunable fishnet unit cell element and the design of an array consisting of these tunable unit cell elements. As the application and characterization of the fishnet structure as effective gradient material is a new field of study, basic investigation redarding the applicability of effective material and Bloch parameters, the unit cell anisotropy, and nearfield coupling will be carried out. To introduce a voltage tunability of the LC layer a biasing strategy will be designed and the phaseshift properties will be investigated. Based on these results the array will be fabricated to demonstrate the beam steering capability of the gradient index fishnet structure. The fishnet array itself has an overall size in the range of several freespace wavelengths but also contains geometrical details which are much smaller than the freespace wavelength. This results in large simulation complexity. Thus, a time- and memory efficient simulation technique needs to be conceived within this project.

该项目建议的目的是设计和研究基于液晶（LC）的可调梯度指数渔网结构，用于应用作为光束转向应用的传输阵列。它的目的是首次使用渔网结构，其横向到入射光束的传播方向的渔网结构不均匀。将梯度的调整通过将液晶作为电压调谐电介质来实现。这样，可以调节渔网结构的分散特性，以实现透射梁的转向。由于渔网结构朝着广阔的方向激发，因此可以应用用于制造可调平面微波组件的技术挑战相对较小且已建立的LC技术。已经表明，可以将渔网结构应用于光学区域。连续可调节的LC应用到THZ区域都有可能。该项目由两个部分组成：可调式渔网单位细胞元件的设计和研究以及由这些可调单元元件组成的阵列的设计。由于将渔网结构作为有效梯度材料的应用和表征是一个新的研究领域，因此将进行有效材料和Bloch参数的适用性，晶胞各向异性和近场耦合。为了引入LC层的电压可调节性，将设计一个偏置策略，并将研究PhaseShift属性。基于这些结果，将制造阵列以证明梯度指数渔网结构的梁转向能力。渔网阵列本身的总体大小在几个自由空间波长的范围内，但还包含比自由空间波长小得多的几何细节。这导致了较大的模拟复杂性。因此，需要在该项目中考虑时间和内存有效的仿真技术。