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Research On Microwave Engineering Applications Of Novel Electromagnetic Metamaterials

Posted on:2017-02-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:K M WuFull Text:PDF
GTID:1108330485488436Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
Electromagnetic metamaterial is a kind of manmade artificial structured composite/material, which shows novel electromagnetic phenomena that cannot be found in natural materials. Specially, the electromagnetic metamaterial with both negative permeability and negative permittivity is also called as negative refractive index material, left handed material, etc. Such kind of electromagnetic metamaterial exhibits the novel electromagnetic phenomena including negative refraction, reverse of Doppler shift, reverse of Cherenkov radiation, reverse of Goos-Hanchen shift, and negative optical force, etc. Based on the previous mentioned novel electromagnetic phenomena and various synthetize methods and structure sizes, electromagnetic metamaterial has found a wide range of applications at acoustic, electromagnetic, optical areas. At the same time, based on the novel ability of controlling the propagation, reflection, and scattering, electromagnetic metamaterial also can be used in the engineering areas of radio frequency, microwave, millimeter wave related wireless communications, electronic circuits, and even optical communications. The application in microwave engineering has attracted most research interests in worldwide, and therefore has got rapid developments and scientific results. However, due the fast developments of new electromagnetic metamaterials, the already achieved targets can be exceeded in a short time, and some new application aspects can be found quickly.In this dissertation, based on the new obtained electromagnetic metamaterials, and for the goals of achieving better performance of electromagnetic metamaterial based devices and new application aspects, three main topics are analyzed in details. These three topics are novel electromagnetic metamaterial absorber with different dielectric thicknesses at both microwave and THz bands, novel multiband compact monopole antenna based on the triple-band single loop metamaterial resonators, and the tunable circular polarized antenna based on the ferrite for the application of UHF RFID readers.1. The absorbing abilities and changing properties of the electromagnetic absorber based on the electromagnetic metamaterial units with different dielectric thicknesses are analyzed in this dissertation. It is found that the new electromagnetic metamaterial absorber with additional half wavelength and whole wavelength thicknesses can also exhibit near perfect absorbing abilities. At the same time, the higher order absorbing modes exhibit similar absorbing abilities and repeatable properties. The interference theory is used to analyze and explain the abserved novel properties. Lastly, it is confirmed that the main function of the ground plan of electromagnetic metamaterial absorber is to reflect the incident electromagnetic waves.2. A novel kind of compact multiband monopole antenna based on the triple-band single loop metamaterial resonators is analyzed systematically. Different radiation patch configurations and different feeding methods are presented in this dissertation to design the new antennas and to understand the intrinsic mechanism, including the impedance matching and radiation properties. It is found that it exhibits the near same impedance matching and radiation properties for all of the discussed antennas. Therefore, such kind of antenna can be used in the wireless communication circuits for different space restricts.3. A tunable circularly polarized patch antenna based on ferrite substrate is analyzed in this dissertation, for universal ultra-high-frequency RF identification applications. The ferrite layer under an applied dc magnetic bias provides the circularly polarized radiation characteristic. Most importantly, ferrite layer can tune arbitrarily the operating frequency band in a wide range covering all the worldwide operating frequency bands of ultra-high-frequency RF identification, by adjusting the dc magnetic bias. Theoretical analysis on the reason to realize circularly polarized properties without perturbation for the radiation patch and the tunability of operating frequency are firstly presented. Numerical demonstrations are then used to confirm the theoretical analysis.After finishing the above main three research topics, this dissertation obtained the absorption properties of the microwave and THz metamaterial absorber with different dielectric thicknesses, and understood the functions of different parts of the metamaterial absorber units. This dissertation also obtained the compact planar monopole antennas based on the single loop resonators with different shapes and different feeding methods, and obtained the tunable circularly polarized patch antenna based on ferrite substrate, which can cover the whole ultra-high-frequency RF identification operating frequency band. These achievements have very important contributions for popularizing the metamaterial techniques in the communication and electronic engineering areas.
Keywords/Search Tags:electromagnetic metamaterial, metamaterial absorber, interference theory, monopole antenna, ferrite, magnetic anisotropy, tunable, UHF RFID
PDF Full Text Request
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