Left-handed Materials And Its Applications In Microstrip Antennas

In recent years,Left-Handed Metamaterial(LHM)has been widely favored in the fields of physics,electromagnetism,optics,and materials science because of its unique electromagnetic properties.This thesis mainly studies the LHM and its application in microstrip antenna,and designs a new microstrip antenna based on LHM.Firstly,the basic theory of LHM is introduced,and the development and research status of LHM are summarized.The realization mechanism of negative permittivity and magnetic permeability are deduced,and the electromagnetic characteristics of LHM are analyzed.By studying the structure of Smith and the structure of the single-ring resonant resonator(SSRR),the characteristics of the LHM with negative dielectric constant and negative permeability are verified,and the influence of the structural parameters on the octagonal SSRR structure of LHM characteristics is further studied.This lay the foundation for the application of LHM in microstrip antennas.Secondly,the basic theory of the microstrip antenna is briefly explained.A high gain microstrip antenna was designed by loading the octagonal SSRR LHM cladding.In addition,the influence of the LHM cladding on the electromagnetic characteristics of the antenna at different heights is analyzed.After loading the octagonal SSRR LHM cladding,the gain of the microstrip antenna is increased by 2.9dB,the half-power beamwidth is reduced by 41°,and the resonant frequency and bandwidth are basically unchanged.It is verified that the LHM cladding has the effect of converging the electromagnetic beam on the microstrip antenna and improving the antenna gain.Finally,the theoretical basis for the miniaturization of the microstrip antenna by LHM is studied.Two miniaturized microstrip antennas are designed by different loading methods,one is based on the left-handed transmission line and the other is based on the circular split single-ring resonant reactor(CSSRR).By loading the left-handed transmission line structure on the patch,the size of the microstrip antenna is reduced by 50.83%compared with that of the traditional microstrip antenna at the resonant frequency of 1.74 GHz.By loading the CSSRR structure on the ground the microstrip antenna,the size is reduced by 37.52%compared with that of the traditional microstrip antenna at the resonant frequency of 5.8 GHz.The antenna is physically processed and its return loss is measured.The measurement results are in good agreement with the simulation results.Therefore,loading LHM can reduce the size of the microstrip antenna and realize the miniaturization design of the antenna.