This article compares the humidity sensing performance of microwave sensors coated with a poly(methyl methacrylate), poly(2‐hydroxyethyl methacrylate), or poly(vinyl alcohol) (PVA) polymer. A microwave sensor based on a modified interdigital‐capacitor‐shaped defected ground structure (IDCS‐DGS) in a microstrip transmission line with enhanced permittivity sensitivity was designed on an RF‐301 substrate with a thickness of 0.76 mm, which operate at a 1.5 GHz microwave frequency under unloaded conditions. One of the three different polymers was coated onto the IDCS‐DGS of the microwave sensors at a thickness of 0.02 mm. The humidity sensing performance of the microwave sensors coated with each of the three polymers was measured by the shift in the resonant frequency and magnitude level of the transmission coefficient when relative humidity was varied from 40 to 90%, with increments of 10%, at a temperature of 25°C. The experiment results show that the humidity sensing performance of the PVA‐coated microwave sensor is the best among the three polymers.

中文翻译：

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涂有PMMA，PHEMA和PVA的有缺陷的基于地面结构的微波传感器的湿度感测性能

本文比较了涂覆有聚甲基丙烯酸甲酯，聚甲基丙烯酸2-羟乙酯或聚乙烯醇（PVA）聚合物的微波传感器的湿度传感性能。在RF-301基板上设计了基于微带传输线中改进的叉指电容器形缺陷接地结构（IDCS-DGS）的微波传感器，该传感器具有0.76 mm的厚度，工作频率为1.5 GHz空载条件下的微波频率。将三种不同的聚合物之一涂在微波传感器的IDCS-DGS上，厚度为0.02 mm。当相对湿度从40％变为90％，以10％的增量变化时，通过共振频率的变化和透射系数的幅度水平，可以测量涂覆有三种聚合物的微波传感器的湿度传感性能。温度为25°C。实验结果表明，在三种聚合物中，涂有PVA的微波传感器的湿度感测性能最佳。