Microwave resonators combined with polymer absorption layers are widely used in volatile organic compound (VOC) detection based on their variable resonant frequencies. However, the response time is limited due to the polymer’s slow volumetric absorption of VOC molecules. By constructing a porous structure in Polydimethylsiloxane (PDMS), resulting in reduced the response time to as short as 71.1%. To mitigate the sensitivity decline caused by the porous PDMS, a trenched-substrate complementary split-ring resonator (CSRR) is proposed for enhancing the interaction between the electromagnetic fields (EMFs) and the porous PDMS with VOCs. The removal of the substrate beneath CSRR’s sensing region enhances the effective EMF, increasing frequency and amplitude sensitivities up to 175.5% and 137.8%, respectively. Responses to four common VOCs by the sensor show a maximum sensitivity of 217 Hz/ppm and a minimum limit of detection of 295 ppm. Additionally, resonant parameters and extracted lumped parameters are utilized to establish two decision-tree-based VOC classification models, achieving high accuracies of 98.71% and 99.59%, respectively. And the latter one fully utilizing responses throughout the swept band, proves superior in identifying similar substances. This sensor technology helps promote the sensitive detection and accurate classification of diverse VOCs.

中文翻译：

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与多孔 PDMS 集成的沟槽式微波谐振器，用于检测和分类 VOC，并具有增强的性能


微波谐振器与聚合物吸收层相结合，因其谐振频率可变而广泛应用于挥发性有机化合物（VOC）检测。然而，由于聚合物对 VOC 分子的体积吸收缓慢，响应时间受到限制。通过在聚二甲基硅氧烷 (PDMS) 中构建多孔结构，将响应时间缩短至 71.1%。为了减轻多孔PDMS引起的灵敏度下降，提出了一种沟槽基底互补开环谐振器（CSRR）来增强电磁场（EMF）和多孔PDMS与VOC之间的相互作用。去除 CSRR 感应区域下方的基板可增强有效 EMF，将频率和振幅灵敏度分别提高至 175.5% 和 137.8%。传感器对四种常见 VOC 的响应显示最大灵敏度为 217 Hz/ppm，最小检测限为 295 ppm。此外，利用谐振参数和提取的集总参数建立了两个基于决策树的VOC分类模型，分别实现了98.71%和99.59%的高精度。后一种方法充分利用整个扫频带的响应，在识别类似物质方面证明具有优越性。该传感器技术有助于促进多种VOC的灵敏检测和准确分类。