This paper reports the development of a wireless pressure sensing coil system by embedding a capacitive micro sensor onto a wire. The coil system, consisting of an inductor (coil itself) and multiple capacitors (sensors), formed a passive LC telemetry configuration for wireless sensing. The capacitive sensor, utilizing the movements of a liquid in a sealed chamber for hydraulic amplification, enabled high capacitance changes and amplified signal outputs. The capacitive sensor also produced digitized signal outputs as the liquid movement crossed a finite number of the interdigitated electrodes. Such characteristics were modeled and confirmed by establishing an equivalent fluidic circuit. The capacitive sensor was fabricated by grafting and polishing a copper wire piece on a silicon wafer, then performing standard microfabrication on the polished wire surface and filling a liquid into a sensor chamber. The fabricated pressure sensing coil system demonstrated a pressure sensitivity of 11.8 kHz/mmHg under a clinical pressure range of 0~206.9 mmHg in an ex vivo test with a water flowing tube, meeting the requirements for wireless detection of vessel restenosis. The sensitivity corresponded to the capacitance changes of 0.052 fF/mmHg and liquid displacement of $0.39~\mu \text{m}$ /mmHg. The fabricated coil system held a dimension of 2.5 mm in diameter and 7.2 mm in length in the form of a wound wire (copper, $260~\mu \text{m}$ in diameter). The embedded capacitive sensor consisted of a hydraulic chamber of $400\times 100\times 1 2\,\,\mu \text{m}^{3}$ and a microchannel of $500\times 20\times 1 2\,\,\mu \text{m}^{3}$ . [2020-0364]

中文翻译：

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压力传感器嵌入式感应线圈向无线压力传感支架发展

本文通过将电容式微传感器嵌入电线来报告无线压力感应线圈系统的发展。线圈系统由一个电感器（线圈本身）和多个电容器（传感器）组成，形成了用于无线传感的无源LC遥测配置。电容式传感器利用密封室内液体的运动进行液压放大，从而实现高电容变化和放大的信号输出。当液体运动越过有限数量的叉指电极时，电容式传感器还会产生数字信号输出。通过建立等效流体回路对这些特性进行建模和确认。电容式传感器是通过在硅片上接枝并抛光铜线制成的，然后在抛光的导线表面上执行标准的微细加工，然后将液体填充到传感器室中。所制造的压力感测线圈系统在临床压力范围为0〜206.9 mmHg的情况下，显示出11.8 kHz / mmHg的压力灵敏度。离体用流水管进行测试，符合无线检测血管再狭窄的要求。灵敏度对应于0.052 fF / mmHg的电容变化和 $ 0.39〜\ mu \ text {m} $ / mmHg。制成的线圈系统的直径为2.5毫米，长度为7.2毫米，采用绕线形式（铜， $ 260〜\ mu \ text {m} $ 在直径上）。嵌入式电容传感器由一个 $ 400 \ times 100 \ times 1 2 \，\，\ mu \ text {m} ^ {3} $ 和一个微通道 $ 500 \ times 20 \ times 1 2 \，\，\ mu \ text {m} ^ {3} $ 。[2020-0364]