Optimization Design Of Microstructure Of Electromagnetic Metamaterials With Prescribed Properties And Optimization Of Metamaterial-based Functional Devices

Because of the special characteristics and important application prospect of EM(electromagnetic)MTM(metamaterials),the corresponding research on EM MTM has been paid much attention.The achievement of peculiar characteristics of MTM is on the basis of its special microstructures,so establishing the selecting or designing method for the MTM microstructures with specific function is necessary.On the other hand,according to MTM's special characteristics,designing the MTM-based EM devices(such as sensors,wave propagating governers and so on)has important reseach significance.Based on the demands above,aiming at design of the MTM micro structure with specific characteristics,taking the existing MTM microstructures as the alternative a selecting method based on fuzzy math is established,for getting LHM(left-handed material)microstructure satisfying the designing demand;The designing method of MTM microstructure based on topology optimization is proposed,and the designing tool for MTM microstructure with specific characteristics is exploit.The research can be used to get MTM microstructure with accurate specific magnitude and bandwidth;The research on the bandgap characteristics and parameters sensitivity of the microstrip line-typed MTM is conducted.The optimization designing method of dielectric thickness sensor based on microstrip line-typed MTM is proposed;The designing method and model of the coaxial line-based electromagnetic bandgap strain sensor is researched;The regulation and controlling method on the EM wave and characteristics of the gradient refractive index metamaterials(GRIN)is analyzed.The details of researching contents and results contain,1.The selecting method of the patched left-handed metamaterials based on fuzzy math.After analyzing the characteristic of the existing MTM microstructures synthetically,classifying and ordering,a reasonable selection on the microstructure to satisfy the demand is an effective method to achieve the designing of the MTM microstructure with specific characteristics.In view of this,the selecting method of the patched LHM microstructure based on fuzzy clustering and membership degree information is established.After establishing the non-empty sets of the existing LHM microstructures,the forms of the subordinate function of characteristics parameters of LHM microstructures in the set are discussed,in order to calculate the membership degree of different designing object and restrain on each microstructure.The relationship between the fuzzy superiority and each membership degree is established.The selecting mechanism for suitable MTM microstructure is determined,which is based on calculating and ordering the fuzzy superiority of each microstructure.One set containing the microstructures with different topology configurations and another set containing the fork-shaped microstructures with different sizes are established.For different aims and constraints,the fuzzy superiority of the corresponding set is calculated and ordered.The result validates that the proposed microstructure selecting method can find the superior microstructure configurations.2.The designing method of patched metamaterials microstructure satisfying specific magnitude and frequency band demand.For specific functional demands accurately,such as the specific magnitude or frequency band,selecting or size-optimizing on the existing MTM microstructure may not obtain the MTM microstructures satisfying the demands accurately.For solving the problem above,a designing method of patched MTM microstructure with specific functional demand based on topology optimization is researched.The topology optimization model for MTM microstructures with specific magnitude or frequency band is established.The method that the patch is bigger than the size of mesh is proposed in order to solve the check-board problem.The models for the MTM microstructures with four kinds of typical specific material parameter demands are introduced detailedly.The demands contain specific negative permeability at the given frequency,specific negative permeability and permittivity at the given frequency,specific frequency band of negative permeability and specific LHM frequency band.The feasibility and robustness of the proposed method are verified according to a mount of examples.Based on the method the designing tool for MTM microstructures satisfying specific functional demand is exploited.3.The research on the bandgap and parameters sensitivity of the microstrip line-typed metamaterials.The microstrip line-typed MTM would exhibit different response to the external dielectric.Confirming the bandgap characteristics and parameters sensitivity is benificial to the proposal of the new sensor and the optimization of the sensor.Based on the considerations above,the bandgap characteristics and responsing 'sensitivity to the external dielectric with different parameters of microstrip line-based CSSRR(Complementary singlesplit ring resonator)are researched.The bandgap characteristics and sensing characteristics to the external dielectric with different thickness or permittivity of CSSRR under two polarization excitations are analyzed.The sensitivity of the different sub-region of metamaterials responsing to the external dielectric is analyzed.Taking the deviation between the real peak frequency shifting and the max peak frequency shift when there isn't any air gap as the detected object,a method for height testing of the air gap between each planar dielectric layer is proposed.According to the simulation and experiment,the bandgap characteristics and sensitivity of the microstrip line-typed MTM are tested and verified.4.The design and optimization on dielectric thickness sensor based on the microstrip line-typed metamaterials.The current works on the sensors based on the microstrip line-typed MTM are mainly to expand its application areas,but the method for microstructure optimization to improve its sensing characteristics is few.The size and topology optimization methods on the dielectric thickness sensors based on the microstrip line-typed MTM for different aims are established.The size of CSSRR on the sensor is optimized for higher sensitivity,and the dielectric thickness sensor based on U-shaped MTM is designed.In order to achieve miniaturization of the sensor,a new dual spiral microstructure is designed and its peak frequency is much lower than the minimal peak frequency the CSRR(Complementary split ring resonator)can supply.The topology optimization method on the MTM microstructure for different design objects is proposed.The design objects contain the specific resonant frequency,the max quality factor and max sensitivity.The simulation and tested results indicate that the characteristics of the optimized sensor is improved obviously compared with CSRR-based and CSSRR-based sensor.5.The design on the coaxial line-based electromagnetic bandgap metamaterials strain sensor.In order to overcome the fragility,low intensity,corrosiveness and seperation of dual peaks of the existing strain sensor based on Bragg grating,a novel coaxial line-based electromagnetic bandgap metamaterials strain sensor is proposed.The correlation between the periodic impedance discontinuity and the bandgap characteristics are analyzed.The electromagnetic bandgap metamaterial structure based on coaxial impedance discontinuity is designed.The methods on the parameters design and theoretical calculation of the bandgap are provided.Two kinds of coaxial electromagnetic bandgap sensors are achieved through section discontinuity and insulating medium discontinuity respectively.The adjustment of its sensitivity and quality factor and the influence from defect are discussed.Its bandgap and sensing characteristics are verified from numerical simulation and experiment.6.The research on the regulation and control method on the electromagnetic wave and the particular characteristics based on the gradient refractive index metamaterials(GRIN).In order to deeply explore the special EM characteristics and the regulation and control ability on EM wave different material distribution of MTM in space produced,the control characteristics on EM wave direction and phase of GRIN is proposed.Based on the conversion between propagating wave and surface wave of GRIN,the MTM distribution in space is designed to reduce the vertical component of oblique wave.The regulation characteristics on the EM wave direction of GRIN is found.On the basis of the characteristics above,the adjustment on the direction and vertical phase difference of the output wave on the output port caused by scattering media is achieved.The vertical phase difference of the scattering or diffracting wave caused by the deviation of the waveguide can also be diminished according to the same principle.