Modified Split Ring Resonators Sensor for Accurate Complex Permittivity Measurements of Solid Dielectrics

In this paper, a sensor using modified Split Ring Resonators (SRRs) is designed, simulated, fabricated, and used for advanced investigation and precise measurements of the real part and imaginary part solid dielectrics’ permittivity. Adding vertical strips tightly coupled to the outer ring of the SRR leads to the appearance of two resonant frequencies at 1.24 GHz and 2.08 GHz. This modified geometry also assures an improved sensitivity. Using the full wave electromagnetic solver, both the unloaded and loaded sensors are investigated. The numerical simulations are used to develop a mathematical model based on a curve fitting tool for both resonant frequencies, allowing to obtain analytical relations for real and imaginary parts of permittivity as a function of the sample’s thickness and quality factor. The sensor is designed and fabricated on 1.6 mm thick FR-4 substrate. The measurements of different samples, such as transparent glass, acrylic glass, plexiglass, and Teflon, confirm that the modified SRR sensor is easy to implement and gives accurate results for all cases, with measurement errors smaller than 4.5%. In addition, the measurements highlight the importance of the second resonant frequency in the cases in which numerical limitations do not allow the usage of the first resonant frequency (1 mm thick sample).

[1]  Daniel Segovia-Vargas,et al.  Submersible Printed Split-Ring Resonator-Based Sensor for Thin-Film Detection and Permittivity Characterization , 2016, IEEE Sensors Journal.

[2]  Measurement of Dielectric Material Properties Application Note , 2012 .

[3]  Dong-Joon Lee,et al.  Free-space measurement of the complex permittivity of liquid materials at millimeter-wave region , 2016, 2016 Conference on Precision Electromagnetic Measurements (CPEM 2016).

[4]  David Dubuc,et al.  Highly-Sensitive Microwave Sensors Based on Open Complementary Split Ring Resonators (OCSRRs) for Dielectric Characterization and Solute Concentration Measurement in Liquids , 2018, IEEE Access.

[5]  Zhu Wang,et al.  Design of a High Sensitivity Microwave Sensor for Liquid Dielectric Constant Measurement , 2020, Sensors.

[6]  J. Pendry,et al.  Magnetism from conductors and enhanced nonlinear phenomena , 1999 .

[7]  Chin-Lung Yang,et al.  Complementary Split-Ring Resonators for Measuring Dielectric Constants and Loss Tangents , 2014, IEEE Microwave and Wireless Components Letters.

[8]  Jing Li,et al.  A High-Sensitivity Microfluidic Sensor Based on a Substrate Integrated Waveguide Re-Entrant Cavity for Complex Permittivity Measurement of Liquids , 2018, Sensors.

[9]  Ling Tong,et al.  Measuring Complex Permittivity of Soils by Waveguide Transmission/Reflection Method , 2019, IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium.

[10]  Xunjun He,et al.  A Compact Thin-Film Sensor Based on Nested Split-Ring-Resonator (SRR) Metamaterials for Microwave Applications , 2011 .

[11]  Gaofeng Wang,et al.  Novel Microwave Sensors Based on Split Ring Resonators for Measuring Permittivity , 2018, IEEE Access.

[12]  A. S. Omar,et al.  Microstrip resonator sensors for determination of complex permittivity of materials in sheet, liquid and paste forms , 2005 .

[14]  Abhishek Kumar Jha,et al.  Design and Application of the CSRR-Based Planar Sensor for Noninvasive Measurement of Complex Permittivity , 2015, IEEE Sensors Journal.

[15]  A. Gharsallah,et al.  Equivalent Circuit Model for Double Split Ring Resonators , 2015 .

[16]  Prasanth Moolakuzhy Narayanan,et al.  Microstrip Transmission Line Method for Broadband Permittivity Measurement of Dielectric Substrates , 2014, IEEE Transactions on Microwave Theory and Techniques.

[17]  J. Ahmadi-Shokouh,et al.  Reconfigurable microwave SIW sensor based on PBG structure for high accuracy permittivity characterization of industrial liquids , 2018, Sensors and Actuators A: Physical.

[18]  M. Akhtar,et al.  Microwave Assisted Non-Invasive Microfluidic Biosensor for Monitoring Glucose Concentration , 2018, 2018 IEEE SENSORS.

[19]  A zirconia cylindrical TM010 cavity for permittivity measurements at 1 GHz , 2018, 2018 IEEE Conference on Antenna Measurements & Applications (CAMA).

[20]  K. T. Muhammed Shafi,et al.  Improved Planar Resonant RF Sensor for Retrieval of Permittivity and Permeability of Materials , 2017, IEEE Sensors Journal.

[21]  K. Schmalz,et al.  Microwave biosensor for characterization of compartments in teflon capillaries , 2012, 2012 42nd European Microwave Conference.

[22]  Lei Xu,et al.  A Microwave Method for Dielectric Characterization Measurement of Small Liquids Using a Metamaterial-Based Sensor , 2018, Sensors.

[23]  Kazunori Takahashi,et al.  Measuring Complex Permittivity of Soils By Coaxial Transmission Line Method and FDTD , 2018, IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium.

[24]  David Dubuc,et al.  Double stub resonant biosensor for glucose concentrations quantification of multiple aqueous solutions , 2014, 2014 IEEE MTT-S International Microwave Symposium (IMS2014).

[25]  V. Varadan,et al.  Free-space measurement of complex permittivity and complex permeability of magnetic materials at microwave frequencies , 1990 .

[26]  M. Jaleel Akhtar,et al.  Design of SRR-Based Microwave Sensor for Characterization of Magnetodielectric Substrates , 2017, IEEE Microwave and Wireless Components Letters.

[27]  Millimeter-Wave Resonant Cavity for Complex Permittivity Measurements of Materials , 2018, 2018 IEEE/MTT-S International Microwave Symposium - IMS.

[28]  Chin-Lung Yang,et al.  Noncontact Measurement of Complex Permittivity and Thickness by Using Planar Resonators , 2016, IEEE Transactions on Microwave Theory and Techniques.

[29]  Margarita Puentes Vargas.  Planar Metamaterial Based Microwave Sensor Arrays for Biomedical Analysis and Treatment , 2014 .

[30]  Mojgan Daneshmand,et al.  A Dual-Mode Split-Ring Resonator to Eliminate Relative Humidity Impact , 2018, IEEE Microwave and Wireless Components Letters.

[31]  Vahid Nayyeri,et al.  A CSRR-Based Sensor for Full Characterization of Magneto-Dielectric Materials , 2019, IEEE Transactions on Microwave Theory and Techniques.