Research On Left-handed Metamaterials And The Applications Of Metamaterials In Antenna

The left-handed metamaterials is a sort of artificial periodic structure in which boththe electric constant ε and the magnetic permeability μ are negative, so it is also becalled DNG. The left-handed metamaterials can be generally divided into the metalresonators structure and composite right/left-handed transmission lines (CRLH TLs)structure. In1967, the former Soviet physicist Veselago firstly proposed the left-handedmetamaterials, but it did not attracted scientists’ attention during the past30years. Untilthe1990s, Perdry&Smith proposed the structure combined split ring resonators (SRRs)with continuous rods (Rods) where the rod provided the negative permittivity andsplit-ring induced the negative permeability, and the left-handed characteristic isverified by the experimental of negative index refraction. The left-handed metamaterialshave many potential applications because of its excellent characteristics, such asnegative refraction index, inverse Doppler effects, inverse Cerenkov radiation effects,subwavelength diffractive. Then, people do more and more research on themeamaterials, especially on its new concepts and applications. In the past, research onthe left-handed metamaterials is mainly concentrated in the microwave frequency,scientists are trying to research the metamaterials in the terahertz and opticalfrequencies now.As an important part of the transceiver communication system, the antenna’sperformance has a direct impact on wireless communication. The specificity of theleft-handed metamaterials can be applied to the antenna to improve the performance ofthe antenna, and this method has become a more and more important direction.In this paper, we introduce the research background and basic characteristics of theleft-handed metamaterials, and investigate the Smith structure verified throughexperimental firstly. Then, we propose two novel left-handed metamaterials, theleft-handed characteristics of the two novel structures are verified through softwaresimulation and experimental test, and the new structures are double P-like structure andlattice-like structure. The double P-like metamaterial is a low-loss single-sidedbroadband left-handed structure, so it can be applied into practical. The tri-band lattice-like metamaterial has a wide range of applications in the field of microwave,such as multi-band filters, WDMs, and couplers.In addition, in the field of the left-handed materials used in antenna, we firstlydiscussed the left-handed metamaterial regarded as the covering layers of the microstripantenna. After loaded with the left-handed metamaterials, the antenna’s directivity andgain are improved, radiation is also on a more focused direction, the antenna’sperformance is raised. Secondly, the composite right/left-handed metamaterials appliedto the microstrip antenna is researched, it induced a stopband to be used to dual-bandbroadband monopole antenna for WiMAX/WLAN and X-band satellite; the proposedsplit ring resonator SRR is also regarded as a stopband, research the tri-band antennawith two stopbands, which can also be applied to WiMAX/WLAN systems. Finally, weinvestigate the left-handed metamaterials used in microstrip patch antenna for RCSreduction.