Research On The Application Of Metamaterials In Microwave Dielectric Sensors

With the rapid development of the internet of things and advent of the fourth industrial revolution,the requirements of sensors are increasing,and traditional sensors are unable to meet development requirements.Microwave sensors have been widely used in industrial,biological and electronic fields due to high sensitivity,low manufacturing cost,and simple measurement process.In these fields,microwave sensors need to accurately detect the permittivity of materials under test.In order to meet the needs of applications,microwave sensors are designed to achieve highsensitivity detection while ensuring miniaturization.Metamaterial technology provides new idea for designing microwave sensors with higher sensitivity and smaller size.Metamaterial resonators have the advantages of high quality factor,steep frequency response,and subwavelength resonance.Therefore,designing microwave sensors with metamaterial resonators attracts researchers.Therefore,this paper mainly focusses on perspective of improving the sensitivity of the microwave dielectric sensor,analyzing the reasons for the enhanced sensitivity of the sensor.The main research work of this paper can be summarized as below:1.Research on dielectric sensors with multiple complementary meta-material resonators.Two dielectric sensors loading microstrip line with multiple resonators are present,where,the first topology consists of complementary electric-LC（CELC）structure,the second topology consist of CELC and complementary split ring resonators（CSRRs）.Because the interresonator coupling could increase the sensitivity to detect the presence of dielectric materials,the second topology is preferred for sensor design.Finally,a dielectric sensor of the second topology is fabricated,and measured results meet simulation results very well.The feasibility and validity of the proposed splitter/combiner microstrip loading coupled metamaterial resonator are verified by this part..2.Research on differential dielectric sensor with coupled CSRR.A differential dielectric sensor based coupled CSRR is proposed.The sensor consists of two independent sensing elements.Differential permittivity sensing is performed by detecting reflection coefficients difference of the two ports.The sensor’s improved sensitivity can be described through circuit model analysis.In order to miniaturize the design and improve the sensitivity further,the meander slot is adopted in the CSRR,which increases the resonator effective capacitance.The sensor with meander slot CSRR performs better sensitivity and relationship between frequency and permittivity through electromagnetic simulation.Finally,the sensor with meander slot CSRR is fabricated and tested,with a good agreement achieved between the extracted values and reference.This part of work provides new solutions for the differential dielectric sensor.