Additively Manufactured Microfluidics-Based “Peel-and-Replace” RF Sensors for Wearable Applications
Additively Manufactured Microfluidics-Based “Peel-and-Replace” RF Sensors for Wearable Applications
复制标题
适用于可穿戴应用的基于微流体的增材制造“剥离和更换”射频传感器
DOI：
10.1109/tmtt.2016.2560177
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发表时间：
2016
影响因子：
4.3
通讯作者：
M. Tentzeris
中科院分区：
文献类型：
--
作者：
W. Su;B. Cook;M. Tentzeris
本文展示了第一种基于微流体的柔性RF传感器，结合了微流体，喷墨打印技术和软光刻技术，这可能会成为第一个“真实世界”的可穿戴“智能皮肤”应用。介绍了一种低成本、快速、低温和零浪费的制造工艺，该工艺可用于实现具有几乎任何类型的嵌入式传感元件的复杂微流体通道网络。出于概念验证的目的，使用该过程制作了可重复使用的柔性微流体传感器原型，该过程仅需要0.6 μ L的流体体积就可以在空通道（Δ r = 1）和充满水的通道（Δ r = 73）之间产生44%的频率偏移，这表明其灵敏度高于大多数先前报道的基于微流体的微波传感器。使用七种不同的流体来测量原型的灵敏度，并且观察到24%/log（μ r）的总体灵敏度。所提出的传感器的"剥离和更换"能力不仅有利于传感器可重复使用性的清洁过程，而且还实现了灵敏度可调性。对于弯曲/贴合配置，即使弯曲半径低至7 mm，该传感器的功能也很好，证明了其极大的灵活性。在多次弯曲后，传感器仍然表现出非常好的性能重复性，这验证了其可重用性。引入的增材制造的基于RF微流体的传感器将非常适合于许多可穿戴和适形流体感测应用（例如，体液分析和食物监测），同时它也可以用于各种微流体可重构微波部件。
This paper demonstrates the first-of-its-kind additively manufactured microfluidics-based flexible RF sensor, combining microfluidics, inkjet-printing technology, and soft lithography, which could potentially enable the first “real-world” wearable “smart skin” applications. A low-cost, rapid, low-temperature, and zero-waste fabrication process is introduced, which can be used to realize complex microfluidic channel networks with virtually any type of sensing element embedded. For proof-of-concept purposes, a reusable and flexible microfluidics sensor was prototyped using this process, which only requires 0.6-μL fluid volume to produce a 44% frequency shift between an empty (ϵr = 1) and a water-filled channel (ϵr = 73), demonstrating a sensitivity that is higher than most previously reported microfluidics-based microwave sensors. Seven different fluids were used to measure the sensitivity of the prototype and an overall sensitivity of 24% / log (ϵr) was observed. The “peel-and-replace” capability of the presented sensor not only facilitates the cleaning process for sensor reusability, but it also enables sensitivity tunability. For bent/conformed configurations, the sensor's functionality is good even for a bending radius down to 7 mm, demonstrating its great flexibility. After bending multiple times, the sensor still exhibits a very good performance repeatability, which verifies its reusability feature. The introduced additively manufactured RF microfluidics-based sensor would be well suited for numerous wearable and conformal fluid sensing applications (e.g., bodily fluids analyzing and food monitoring), while it could also be utilized in a variety of microfluidics-reconfigurable microwave components.