Research On The Design And Application Of New Three-dimensional Left-handed Materials

The left-handed material is a synthetic electromagnetic material,which has some electromagnetic characteristics different from those of media materials in nature and is widely used in the fields of medicine,communication and military.In this paper,three new types of left-handed material structures were designed based on the electromagnetic properties of left-handed materials and the principles of structural design,and their applications in the field of magnetic resonance were simulated.Firstly,a two-dimensional left-handed material structure was designed based on the analysis and summary of the basic theory and electromagnetic properties of the left-handed material,and the electromagnetic calculation and analysis were carried out.secondly,a new type of multiopen ring-shaped three-dimensional left-handed material structure was designed based on the two-dimensional left-handed material.The structure was subjected to electromagnetic calculation and analysis to explore its electromagnetic properties.Finally,a metalmedium model three-dimensional left-handed material structure was designed and applied to the 7T magnetic resonance imaging,the effect of left-handed materials on the RF field and energy deposition were analyzed.Firstly,the electromagnetic law of the left-handed material was theoretically analyzed,and the electromagnetic characteristics of the left-handed material were summarized.A two-dimensional left-handed material structure was designed,and the software HFSS15.0 was used to perform electromagnetic analysis on it,calculated S parameters,and invert the method extracted its equivalent electromagnetic parameters and verified that the structure satisfies the left-handed characteristics.Secondly,a three-dimensional left-handed material structure with a multi-opening ring that realized left-handed characteristics in the resonant frequency band of 200 MHz to369.7MHz was designed.Through the calculation of the figure of merit,the threedimensional left-handed material structure was proved to be a low-loss structure the influence of the change of the structure size parameter on the S parameter and the equivalent electromagnetic parameter was discussed.Thirdly,a three-dimensional left-handed material structure of a metal-medium model was designed,and the structure was electromagnetically calculated and analyzed,and it was verified that it satisfied the electromagnetic properties of the left-handed material.Finally,the three-dimensional left-handed material structure was used in 7T human brain magnetic resonance imaging,and the influence of the left-handed material structure on the uniformity of the RF field and energy deposition was simulated and analyzed.