The Application And Research Of Near Zero Index Refraction Metematerials Used In Circularly Polarized Antenna

In recent years,metamaterials have got more and more attention for its novel properties which differ from the natural materials,for example,some structures presents negative permittivity and permeability when they are arranged periodically.Metamaterials have been one of the research hotspots in physic science,material science and electromagnetic science.Zero-index-refraction materials can make the outgoing wavefront parallel with the outgoing material surface for its zero refraction feature,so it can change the propagate direction of electromagnetic wave and it has the effect of wavefront shape.Meanwhile,for the zero permittivity materials,they have the electromagnetic tunneling effect.These novel features make the zero-index-refraction materials have tremendous applicative prospect in wireless communication area.Using these novel features reasonably in some significant areas can break through the traditional technology limitation and improve the capabilities.The near-zero-index-material in this paper is one kind of the artificial metamaterials,and it can improve the antenna's capabilities efficiently if we apply it into circularly polarized antenna.The main works we have done in this paper are listed as follows:(1)The zero-index-refraction material method which must satisfy circularly polarized antenna's requirement was studied,and some structures that have already been designed in literatures was analyzed,then the appropriate one was chosen.To prove our idea's correction,we established a model and simulated the structures,the results indicated that all the three structures can be used in circularly polarized antenna.(2)One circularly polarized horn antenna which resonates at 8.4GHz by using T-shape power divider was designed,then ENZ material,MNZ material and DNZ material was loaded to the horn antenna respectively to investigate how the material influenced the horn antenna's capabilities such as gain,HPBW,axial ratio and S11,the results indicated that all the three zero-index-refraction materials can improve the horn antenna's gain and decrease HPBW while shift the frequency of S11 and axial ratio.(3)One circularly polarized patch antenna was designed,then ENZ material,MNZ material and DNZ material was loaded to the patch antenna respectively to investigate how the material influenced the patch antenna's capabilities such as gain,HPBW,axial ratio and S11,the results indicated that all the three zero-index-refraction materials can improve the patch antenna's gain and decrease HPBW while shift the frequency of S11 and axial ratio.Moreover,the materials' size was changed to investigate how the materials'size influenced the patch antenna's gain,HPBW,axial ratio and S11.