| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 98 === The permittivity and permeability of matters are the essential physical quantity of electromagnetics. The material properties are positive. The negative material properties can be realized by using artificial structures. Acoustic metamaterials, as a counterpart to electromagnetic metamaterials, can be explored.The novel properties of acoustic metamaterial will offer many opportunities in wave engineering.
Resolution of conventional acoustics is generally constrained by diffraction limit, which prevents imaging of near field pressure source in the far-field zone. In this thesis, We study the imaging properties of hyperlens, which proffer subwavelength pattern originated from near-field sources and form images in the far-field zone with high resolution. According to the theory of effective medium, a hyperlens can be realized by using acoustic metamaterials. The imaging properties of hyperlens are studied numerically using finite element method. Numerical simulations show the acoustic hyperlens is concrete feasibility.
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