基于开口谐振环结构的介电常数测量传感器研究

Research on Permittivity Measurement Sensor Based on Split-Ring Resonator Structure

固态材料介电常数的测量常采用双端口传感器,但传感器尺寸较大。针对此问题,设计了一款单端口特性的射频传感器,尺寸仅为30 mm×40 mm。射频传感器采用开口谐振环结构,选用介电常数为4.4的FR4材料作为传感器基板,厚度为1 mm。首先使用电子设计自动化软件ADS设计了传感器,并对加载不同介电常数模型的传感器进行仿真,以得到不同介电常数下的回波损耗S11;随后使用MATLAB对S11谐振频率进行处理,得到待测样品厚度为0.8 mm时的拟合公式。最后,将实测数据代入拟合公式得到材料介电常数的测量值,并与样品介电常数标准值比较。实验结果表明,使用该射频传感器测量Rogers 5880得到的介电常数为2.18,误差为0.91%;测量FR4得到的介电常数为4.32,误差为1.82%。因此,所设计的射频传感器可以用于固态材料介电常数的精准测量。

Dual-port sensors are often used for the measurement of the permittivity of solid materials,but the sensor size is large.To address this problem,a single-port characteristic RF sensor with a size of only 30 mm×40 mm is designed.The RF sensor adopts split-ring resonator structure,and FR4 material with the permittivity of 4.4 is selected as the sensor substrate,the thickness of which is 1 mm.Firstly,the electronic design automation software the ADS is used to design the sensor and simulate the sensor loaded with different dielectric constant models to obtain the return loss of S11 with different permittivity.Subsequently,the resonant frequency of S11 is processed by using MATLAB to obtain the fitting equation for the thickness of the sample to be measured of 0.8 mm.Finally,the measured data are combined with the fitting formula to calculate the measured values of the material permittivity and compared with the standard values of the sample permittivity.The experimental results show that the permittivity obtained by using this RF sensor is 2.18 with an error of 0.91%for Rogers 5880 and 4.32 with an error of 1.82%for FR4.Therefore,The designed RF sensors can be used to accurately measure the permittivity of solid-state materials.