Design Of Metamaterial Lens For Magnetic Resonance Imaging

Metamaterials are artificial periodic or non-periodic structures composed of electromagnetic resonators. These resonators are usually smaller than one tenth of freespace wavelength. Metamaterials can be designed to have electromagnetic properties difficult or impossible to find in nature. In this paper, we focus on the design and realization of metamaterial superlens for magnetic resonance imaging. It contains choice for resonator element, optimization of geometry parameters, simulation method, retrieval of the effective parameters, fabrication of3D smples, characterization of samples.First, with the parameter sweep method by CST, we designed different metameterial superlens for both high and low field MRI system. For1.5T MRI system, we use a non-magnetic capacitively loaded split ring resonator,using the transmission line model of the structure can be calculated as corresponding to the structure of a given resonant frequency. For3T MRI system, we choose a square spiral resonator, and give the parameter of the resonator by simulation method. For0.35T MRI system, we use a non-magnetic inductively and capacitively loaded double split ring resonator. and we achieve a unit cell that is λ/a≈1000.Subsequently, we fabricate two samples of the electromagnetic superlens suitable for1.5T and0.35T MRI system respectively. We use a vector network analyzer to finish the resonance characteristics. With MRI experiment, we verify the usefulness of the metamaterial superlens for improving the image quality of magnetic resonance imaging.At the end of this thesis, we summarize all the content and give the research plan for future.