功能驱动的超材料结构数字化设计与3D打印

Abstract

A new design method is proposed in the present paper to realize the digital design of metamaterial structures driven by microwave transmittance performance. An Eaton lens, which can transmit the incident microwave beam in the 90° direction, is designed as a demonstration of the proposed design method. The digital discretization method for the theoretical model of the Eaton lens is investigated in order to obtain an engineering model with permittivity distribution. The relationship between effective permittivity and geometric parameters of the unit cell, such as width of the pillar- w and the lattice constant- a in the woodpile structure, is investigated. Therefore, an engineering model of the permittivity distribution can be transformed into a structure model using the woodpile structure as the unit cell. The 3D 90° Eaton lens with integrated micro and macro-structures is realized using a photo-curable resin with permittivity of three, a liquid mixture with permittivity that ranges from 2.2 to 40 as the raw material, and stereolithography as the 3D printing process. The controllable propagation with 90° reflection of the incident microwave on the fabricated Eaton lens is validated through experiment results and simulation. Moreover, broadband transmittance performance is achieved on the frequency range from 12 GHz to 18 GHz. The method proposed in the present research provides a new strategy for realizing a new microwave device with novel transmittance performance by combining the digital design method and 3D printing process.