A Research On Characteristics Of Circular Waveguide Loaded With Metamaterials

In recent 20 years,Metamaterials have been the hot and leading topic in current research with its unique electromagnetic in the fields of electromagnetics,solid state physics and materials science.A series of singular electromagnetic properties have been found in artificial metamaterials,compared with ordinary medium,such as left hand characteristics,backward wave characteristics,negative refraction characteristics and reversed Doppler effect.It has opened a new direction for the field of electromagnetics.Artificial metamaterials have great potential for application in waveguides,such as waveguide miniaturization and filter and so on.However,the current researches are mainly focused on planar waveguides and rectangular waveguides.And the related researches on circular waveguides,which is commonly used in high-power microwave and resonator,are lacking.In this paper,the transmission characteristics of the artificial metamaterial after the round waveguide is studied.First of all,this paper briefly describes the research background and significance of artificial metamaterials.Then,the singular electromagnetic properties of artificial metamaterials are studied from its basic concept.And two methods for the construction of artificial metamaterials were analyzed,which are the resonant structures and the artificial metamaterials with CRLH-TLs.Then,starting from the Maxwell's equations and combining with the principle of negative magnetic permeability of Split-Ring Resonators?SRR?,and the reason why the electromagnetic wave stopbands are produced in the waveguide loaded with the SRR is discussed.Afterwards,A ka-band artificial metamaterial based on SRR is designed,and the influence of structural parameters of SRRs on its electric field characteristics is simulated with HFSS software.After that,the designed SRRs are loaded into the circular waveguide.With the principle of generating the stopband of the electromagnetic wave,a radially arranged array of SRR is designed.The TE₀₁ mode in the circular waveguide could be transmitted and the other modes could be attenuated.And through HFSS simulation analysis,simulation results have been shown that it has attenuation effect on microwave except for TE₀₁mode,and it can enhance attenuation performance by decreasing the rotation center angle or increasing column number.And then,based on the principle of the same stop-band generation,other methods for circular waveguides loaded with artificially metamaterial were designed and verified by HFSS software.Finally,based on the previous simulation design,this paper designs a verification experiment for the propagation characteristics of a circular waveguide loaded with artificial metamaterials at the ka-band.The experimental result has shown that the transmission characteristics of the circular waveguide loaded with artificial metamaterials can be changed.There is almost no attenuation in the TE₀₁1 mode,while there are different degrees of attenuation in other modes.The test is basically consistent with the simulation.