Complex Permittivity of NaOH Solutions Used in Liquid-Metal Circuits
Complex Permittivity of NaOH Solutions Used in Liquid-Metal Circuits
复制标题
DOI：
10.1109/access.2019.2945773
复制
发表时间：
2019-01-01
期刊：
影响因子：
3.9
通讯作者：
Ohta, Aaron T.
中科院分区：
文献类型：
--
作者：
Elassy, Kareem S.;Rahman, M. Arifur;Ohta, Aaron T.
镓合金在室温下是液体，适合作电子电路的导体。此外，浸在水基电解质（如氢氧化钠（NaOH））中的镓基液态金属可以被电驱动，从而实现射频开关、可调谐滤波器和可调谐天线等可重构电子设备。然而，液态金属可重构电子器件中的NaOH也会导致射频损耗，应通过仔细设计和模拟将其最小化。为了准确地模拟微波频率下NaOH的影响，在工作频率范围内需要NaOH的复介电常数。本文用介电光谱法测定了NaOH水溶液在0.2 ～ 20 GHz范围内的复介电常数。研究了浓度为0.01 mol /l (M)、0.1 M、0.25 M、0.5 M、0.75 M、1.0 M、1.25 M和1.5 M的NaOH溶液在20℃下的复介电常数谱，并采用Cole-Cole弛豫时间分布拟合。此外，报告了拟合参数，包括静介电常数$\varepsilon _{s} $和弛豫时间$\tau $，以及分布参数$\alpha $。利用测量的NaOH介电常数模拟了两种使用NaOH的液态金属射频元件。测量的射频性能与模拟结果吻合良好，其中包括NaOH的影响。
Gallium alloys are liquids at room temperature, and are suitable as conductors in electronic circuits. Furthermore, gallium-based liquid metals immersed in a water-based electrolyte such as sodium hydroxide (NaOH) can be electrically actuated, enabling reconfigurable electronics such as RF switches, tunable filters, and tunable antennas. However, NaOH in liquid-metal reconfigurable electronics also causes RF losses that should be minimized by careful design and simulation. To accurately simulate the effects of NaOH at microwave frequencies, the complex permittivity of NaOH is required over the operating frequency range. Here, the complex dielectric permittivity of aqueous NaOH solutions is determined from 0.2 to 20 GHz by dielectric spectroscopy. NaOH solutions with concentrations of 0.01 moles/liter (M), 0.1 M, 0.25 M, 0.5 M, 0.75 M, 1.0 M, 1.25 M, and 1.5 M are investigated at 20 C. The complex permittivity spectra are fitted by a Cole-Cole relaxation time distribution. In addition, the fitting parameters, including static permittivity $\varepsilon _{s} $ and relaxation time $\tau $ are reported, along with the distribution parameter $\alpha $ . The measured permittivity of NaOH is used to simulate two liquid-metal RF components using NaOH. The measured RF performance are in good agreement with the simulated results that include the effects of NaOH.