A readout circuit for wireless passive LC sensors and its application for gastrointestinal monitoring
A readout circuit for wireless passive LC sensors and its application for gastrointestinal monitoring
复制标题
无线无源LC传感器读出电路及其在胃肠监测中的应用
DOI：
10.1088/0957-0233/25/8/085104
复制
发表时间：
2014-08-01
影响因子：
2.4
通讯作者：
Wang, Junbo
中科院分区：
文献类型：
--
作者：
Bao, Kaikai;Chen, Deyong;Wang, Junbo
提出了一种用于无线无源LC传感器的读出电路，其中电感-电容（LC）谐振电路与读出线圈相结合，用于谐振频率检测。由于互感，读出线圈的阻抗相位在传感器谐振频率附近显示一个“倾角”。以前，相位倾角在低耦合系数条件下（特别是在植入情况下）振幅有限，给便携式检测带来麻烦。为了解决这个问题，本研究提出了一种新的差分转导电路，并进行了理论分析和数值模拟。与传统的转导电路（如I-V电路和自动平衡桥电路）相比，差分电路对相位变化更敏感，可以更可靠、更精确地检测谐振频率。此外，所提出的读出电路被用于检测兔的胃肠压力空组10 mm × 14 mm的LC压力传感器，在LC传感器和读出电路之间的工作距离高达60 mm。实验结果显示，测量分辨率低于0.4 kPa，测量速度为8次/ s。
A readout circuit is presented for wireless passive LC sensors, where an inductor-capacitor (LC) resonant circuit was combined with a readout coil for resonant frequency detection. The impedance phase of the readout coil shows a 'dip' near the sensor's resonant frequency due to the mutual inductance. Previously, the phase-dip has suffered from limited amplitude in the low-coupling-coefficient condition (especially in the case of implantation), rendering portable detection troublesome. To address this issue, in this study a new differential transduction circuit was proposed where both theoretical analysis and numerical simulations were performed. Compared to conventional transduction circuits (e.g., the I-V circuit and the auto-balancing bridge circuit), the differential circuit was more sensitive to the phase change, enabling more reliable and precise resonant frequency detection. Moreover, the proposed readout circuit was used to detect the gastrointestinal pressure of rabbits with a empty set10 mm x 14 mm LC pressure sensor at an operational distance of up to 60 mm between the LC sensor and the readout circuit. Experimental results recorded a measurement resolution lower than 0.4 kPa and a measurement speed of eight times per second.