How to monitor the freshness of packaged food, the safety of sealed medicine, or the other substances in sealed space wirelessly and environment-friendly has become an urgent problem in recent years. After summarizing the theory of the LC sensor, a design of a paper-based resonator (30 mm × 30 mm × 0.15 mm) consisting of a finger capacitor is proposed in this paper. The sensor is embedded inside the package by adhering it to the package's inner wall. Its response is remotely detected through a readout coil. This paper establishes a circuit simulation model and an electromagnetic simulation model to verify the feasibility of the design. Compared with the real object and the theoretical simulation model, the difference between the results only within 1 MHz, which verifies the correctness of the theory. Additionally, the measured results indicate that the resonant frequency of the resonator shifted from 102.441 MHz to 88.195 MHz, after dropping water on the sensor. Besides, the simple fabrication technology and inexpensive sensor material ensure a low cost, thus making this technology economically viable.

中文翻译：

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弯曲不敏感纸基LC无线无源传感器的优化与设计

如何无线、环保地监测包装食品的新鲜度、密封药品的安全性或密封空间内的其他物质，已成为近年来亟待解决的问题。在总结了 LC 传感器的理论之后，本文提出了一种由手指电容器组成的纸基谐振器（30 mm × 30 mm × 0.15 mm）的设计。传感器通过将其粘附在包装内壁上而嵌入包装内。通过读出线圈远程检测其响应。本文建立了电路仿真模型和电磁仿真模型来验证设计的可行性。与实物和理论仿真模型相比，结果的差异仅在1 MHz以内，验证了理论的正确性。此外，测量结果表明，在传感器上滴水后，谐振器的谐振频率从 102.441 MHz 偏移到 88.195 MHz。此外，简单的制造技术和廉价的传感器材料确保了低成本，从而使该技术具有经济可行性。