Research on chipless and passive architectures for environmental sensing is generating high interest because they do not require any semiconductor components or batteries to operate, thus resulting in an eco‐friendlier footprint. This study demonstrates a printed microstrip line with multiple resonators using biodegradable materials to continuously monitor temperature and relative humidity (RH). Constructed with a paper substrate and printed zinc conductive lines, and encapsulated with beeswax to protect against the interference of humidity, the microstrip line integrates spiral‐shaped resonators. One resonator operates at 1.2 GHz for temperature sensing, while another, coated with konjac glucomannan serves for relative humidity sensing at 2 GHz. The multi‐resonating features allow for a simultaneous assessment of temperature and humidity. The microstrip line displays a linear sensitivity to temperature of −1.35 MHz °C−1 and a non‐linear relative humidity sensitivity ranging between −0.8 and −8 MHz/%RH from 30% to 70% RH. Its degradation in a lab‐made compost for 70 days shows the removal of the transducing layer in 7 days and degradation of the cellulosic substrate starting after 5 weeks. The developed environmental sensing devices are notably promising for future applications in smart packaging and the tracking of goods aiming at the minimization of electronic waste.

中文翻译：

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用于无芯片温度和湿度传感的可降解印刷微带线


用于环境传感的无芯片和无源架构的研究引起了人们的高度兴趣，因为它们不需要任何半导体元件或电池来运行，从而产生更环保的足迹。这项研究展示了带有多个谐振器的印刷微带线，使用可生物降解材料来连续监测温度和相对湿度 (RH)。微带线由纸基板和印刷锌导电线构成，并用蜂蜡封装以防止湿度干扰，集成了螺旋形谐振器。一个谐振器工作频率为 1.2 GHz，用于温度传感，而另一个涂有魔芋葡甘露聚糖的谐振器工作频率为 2 GHz，用于相对湿度传感。多重共振功能可以同时评估温度和湿度。微带线对温度的线性灵敏度为−1.35 MHz °C−1，非线性相对湿度灵敏度范围为−0.8 至−8 MHz/%RH（从 30% 到 70% RH）。它在实验室制造的堆肥中降解 70 天，表明转导层在 7 天内被去除，纤维素基质在 5 周后开始降解。所开发的环境传感设备在智能包装和旨在最大限度地减少电子废物的货物跟踪方面的未来应用前景非常广阔。