| With the rapid development and wide application of the Internet of Things(Io T)technologies,new challenges arise for the sensing of dynamic and static characteristics of objects,such as high-precision and high-reliability temperature and humidity sensing.Exploring and developing new types of sensing mechanisms and realization technologies for the temperature,humidity and other dynamic and static physical characteristics has become a research hotspot in academia and industry.The temperature sensing sensitivity,precision,and linearity directly determine the performance and reliability of Io T nodes.The new artificial electromagnetic structures(also called as metamaterials)have unique electromagnetic characteristics such as negative dielectric constant,negative permeability,negative refractive index,and most importantly the strong electromagnetic resonance,and the peculiar electromagnetic properties such as negative refraction,inverse Cerenkov radiation,inverse Doppler effect and so on.Among them,the high-Q artificial electromagnetic structures composed of temperature-sensitive materials such as mercury(Hg)and gallium indium alloy have quite strong resonance characteristics,highly controlled by ambient characteristic parameters such as the temperature.According on this mechanism,novel artificial electromagnetic structure temperature sensing devices and systems with high-sensitivity,high-precision and wide dynamic range can be developed,which have broad application prospects in military and civilian areas.Therefore,it is of great scientific significance to investigate and develop the key technologies such as structure synthesis mechanisms,design and fabrication methods,the electromagnetic response characteristics analysis method,the temperature controlling rules,the temperature sensing mechanisms,and the test methods of high-Q Hg-based artificial electromagnetic structures.Based on the research and analysis of the relationships between the strong resonance characteristics of Hg-based artificial electromagnetic structures and the structural dimensions and material characteristic parameters,this dissertation established a linear/nonlinear model between temperature sensing performance parameters and electromagnetic structure characteristic parameters such as the resonance frequency.Moreover,a variety of new Hg-based artificial electromagnetic structures with high-Q and strong resonance characteristics have been designed and developed,and the electromagnetic characteristics and temperature sensing performances of these new temperature sensing devices have been studied by simulations and experiments.Finally,the integrated high-performance Hg-based artificial electromagnetic structure temperature sensor has been designed and implemented,and its performances have been investigated by theoretical analysis and experiments.The main research contents and innovative contributions of this dissertation are shown as follows:1.Based on the research and analysis of the nonlinear coupling characteristics between the electromagnetic induction force and the structural resistance in the artificial electromagnetic structure,a power controllable and tunable artificial electromagnetic structure based on low-loss liquid medium is designed,and then the nonlinear coupling mechanism and dynamic coupling process,and the balance characteristics between the electromagnetic induction force and low-loss fluid resistance,and the resulted power controllable and tunable characteristics in the liquid-based artificial electromagnetic structure are revealed.The power controllable and tunable performances of the resonance characteristics for the fabricated C-band artificial electromagnetic structural units in two different low-loss liquid medias are experimentally studied,and the resonance frequency offset value of up to 300MHz is obtained with the incident electromagnetic wave power range from 25 d Bm to 30 d Bm.Those results have shown that the theory proposed to analyze the operating mechanism/EM characteristics of the liquid-based power controllable and tunable artificial electromagnetic structure and its design methodology are viable and effective.2.Based on the power controllable and tunable mechanism of the liquid-based artificial electromagnetic structure,a temperature controllable and tunable Hg-based artificial electromagnetic structure is proposed.Various high-Q strong resonant Hg-based artificial electromagnetic structural units including the quasi-EIT type,reflective type,asymmetric Fano/Torodial type,Anapole type resonators are designed and developed.The strong resonance characteristics and temperature controlling performances of the above-mentioned high-Q Hg-based artificial electromagnetic structures are experimentally studied as well.The maximum deviation of the resonance frequency in the S-band is 200 MHz,and the obtained Q value is as high as 240 within the temperature control range of 12°C.The measured performance for the proposed Hg-based artificial electromagnetic structures is better than those of a variety of temperature-controllable and tunable artificial electromagnetic structures reported before.3.The absorbing and heating effects of the reflective-type high-Q Hg-based artificial electromagnetic structures are theoretically studied here in details.The nonlinear coupling theory model of electromagnetic wave energy-heat energy-mercury column potential energy interaction effect in this kind of reflective-type Hg-based artificial electromagnetic structure are well established.The absorbing and heating effects have been investigated and verified by the corresponding multi-physics coupling simulations and the experiments.The results have revealed the absorbing and heating effects mechanism in the reflective-type high-Q Hg-based artificial electromagnetic field,the dynamic response characteristics of the absorbing and heating effect,and the way to control and obtain the absorbing heating effects as well.The experimental tests have shown that the C-band reflective-type Hg-based artificial electromagnetic structure has a resonance frequency shift of about 30MHz with the incident electromagnetic wave power variation range from 25 d Bm to 35 d Bm in a fixed ambient temperature condition.Those results can help to lay the foundations of reducing the nonlinear temperature measuring error of the Hg-based artificial electromagnetic structure temperature sensor by theoretical and experimental studies.4.A new miniaturized,high-precision Hg-based artificial electromagnetic structure temperature sensor scheme is proposed by integrated the low-power broadband adjustable signal generator,high-precision signal acquisition and processing circuits and other components with the coupled microstrip line.An integrated high-precision Hg-based artificial electromagnetic structure temperature sensor prototype is designed and implemented.The temperature sensing sensitivity and precision performances of the developed temperature sensor prototype are experimentally studied,the measurement results show its temperature sensing accuracy is up to 1.4×10-4°C.This performance parameter is better than those of many high-precision temperature sensors based on the optical waveguide or fiber that have been reported recently.This dissertation has systematically investigated and revealed the temperature controllable and tunable mechanism and performance controlled way of Hg-based artificial electromagnetic structure,established the theoretical analysis,simulation and measurement methodologies for the analysis of the mechanisms and characteristics of the Hg-based artificial electromagnetic structure and its temperature sensor,and developed a high-precision Hg-based artificial electromagnetic structure temperature sensor prototype.The research results will be beneficial to promote the technology development of Hg-based artificial electromagnetic structures and its applications in the areas of electromagnetic characteristics control and high-precision temperature sensing. |
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