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Microwave Resonant Cavity Sensor for Liquid Identification

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Abstract
RF Dielectric spectroscopy (DS) is a powerful monitoring technique thatcan quickly and accurately characterize the properties of various materials.Based on this principle, Radio frequency (RF)-based liquid detection andclassification sensors have been widely studied in recent years and variousRF-based sensors are being developed. In this thesis, we consider theproblem of distinguishing liquids of similar electrical properties and proposetwo electromagnetic wave-based types cavity resonator sensor. Theworking principle of the proposed sensor is based on the fact that thechange in permittivity of liquid samples inside cavity sensor will also causea change in resonant frequency. The proposed resonator sensors consist ofmetal cavity that resonates according to the permittivity of liquid and amonopole that excites electromagnetic waves. For experiments, six differentgasoline samples of permittivity in the range of 2.018 to 2.218. By using agasoline permittivity of room temperature and changing sensor parameters,the sensors were designed by high-frequency structure simulator (HFSS).The designed sensors are cylindrical and rectangular type and have resonantfrequencies of 7.119GHz and 5.13GHz for normal gasoline, respectively. Thecylinder sensor is designed to distinguish the five gasoline samples, and therectangular sensor to distinguish the six gasoline samples with additive newsample of permittivity difference of 0.016 with others. We obtain 8 MHzresonance separation sensor at room temperature to the sample of closestpermittivity by the rectangular sensor experiments and 18 MHz by thecylindrical sensor experiments. To verify the feasibility of the fabricatedsensors under temperature variation, experiments have been carried outusing thermostatic chamber and vector network analyzer (VNA). Theminimum frequency separation to distinguish gasoline samples of thecylindrical sensor is found to be larger than 29 MHz with reflectioncoefficients under -11 dB when temperature changes from -35°C to 0°C. Toverify the feasibility of the fabricated sensor under temperature variationfrom 0°C to 20°C by using the rectangular sensor, we derived a simplelinear distinction function of resonance frequency and S11 parameter and weobtained a minimum 4.4MHz resonance separation by the function.These results showed that the distinction performance for normal gasolineis robust to temperature variations. Through simulations we also showedthat the distinction property is robust to design parameter errors, installationposition variations and sensing time variations. These results show that theproposed sensor can be utilized effectively for distinguishing different DIgasoline.
Author(s)
Jeong, Yoon Sang
Issued Date
2021
Awarded Date
2021. 2
Type
Dissertation
URI
https://oak.jejunu.ac.kr/handle/2020.oak/23801
Alternative Author(s)
정윤상
Affiliation
제주대학교 대학원
Department
대학원 지구해양융합학부 해양시스템전공
Advisor
Lee, Chong Hyun
Table Of Contents
1. INTRODUCTION 1
2. CYLINDRICAL CAVITY SENSOR 4
2.1 Sensor Modeling and Design 4
2.2 Simulations Results of the Proposed Sensor 8
2.3 Experimental Results and Discussions 14
2.3.1 Experimental Setup 14
2.3.1 Results and Discussion 15
3. RECTANGULAR CAVITY SENSOR 22
3.1 Sensor Modeling and Design 22
3.1.1 Theory and Principle of Operation 22
3.1.2 Sensor Design and Simulation Results 25
3.1.3 Sensitivity Analysis of The Sensor 30
3.2 Experimental Results and Discussion 35
3.2.1 Sensor Fabrication and Verification 35
3.2.2 Experiment at Various Temperatures 39
4. CONCLUSION 44
REFERENCES 45
Degree
Master
Publisher
제주대학교 대학원
Citation
Jeong, Yoon Sang. (2021). Microwave Resonant Cavity Sensor for Liquid Identification
Appears in Collections:
Faculty of Earth and Marine Convergence > Ocean System
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