标题： 基于SIW技术的光子晶体腔用于超高灵敏度土壤湿度检测 显示英文标题

标题： Ultra High Sensitivity Soil Moisture Detection Using Photonic Crystal Cavity with SIW Technology

摘要： 土壤养分和含水量是显著影响农业产量的两个关键因素。 因此，监测和测量含水量和土壤类型是关键要求。 本研究提出了一种以对称十字形槽为中心的二维光子晶体结构。 十字形槽作为谐振器，围绕槽的光子晶体调节谐振器的共振频率，以增强谐振器内的模式限制。 各种谐振模式位于2.1 GHz、5.2 GHz和8.1 GHz频段，分别对应S波段、C波段和X波段。 这些频段用于比较吸收情况，而上部谐振模式约为20 GHz。 带结构分析是使用平面波方法（PWM）进行的。 谐振频率是通过使用有限元法（FEM）的三维电磁（EM）仿真软件计算的，并位于光子晶体带结构的辐射模式区域。 改变入射角对传感器的吸收特性影响可以忽略不计，使其无论入射角如何都能产生准确的传感结果。 通过这种设计最大化传感器的灵敏度，在2.1 GHz谐振频率下灵敏度达到85.4%，这比基于光子晶体的SIW单列的灵敏度高出许多，在2.1 GHz时灵敏度为50.6%，此时存在约GHz量级的频率偏移。 相比之下，在所提出的設計中，频率偏移在MHz量级，从而实现了超高灵敏度。 显示英文摘要

摘要： Soil nutrients and water content are two crucial factors that significantly affect agricultural production yields. Hence, monitoring and measuring the water content and soil type are critical requirements. This study proposes a two-dimensional structure of photonic crystals centered around a symmetrical cross-shaped slot. The cross-slots act as resonators, and the photonic crystals surrounding the slots tune the resonance frequency of the resonators to enhance mode confinement within the resonator. The various resonant modes are located in the 2.1 GHz, 5.2 GHz, and 8.1 GHz bands, which correspond to the S band, C band, and X band, respectively. These bands are used to compare the absorption, whereas the upper resonant mode is of the order of 20 GHz. Band structure analysis was performed using the Plane Wave Method (PWM). The resonant frequency is computed using a 3D electromagnetic (EM) simulation software that utilizes the Finite Element Method (FEM) and lies in the radiation mode region of the band structure of the photonic crystal. Varying the incident angle had a negligible effect on the absorption characteristics of the sensor, allowing it to produce accurate sensing results regardless of the incident angle. The sensor's sensitivity is maximized using this design, which results in a sensitivity of 85.4 % in the 2.1 GHz resonant frequency, which is much higher than that of a single column of photonic crystal-based SIW, resulting in 50.6 % of sensitivity at 2.1 GHz, at which there is a frequency shift of the order of GHz. In contrast, in the proposed design, the frequency shift is on the order of MHz, resulting in ultra-high sensitivity.