太赫兹表面波3D打印金属梯度折射率透镜天线

Terahertz surface-wave 3D-printed metallic gradient-index lens antennas

摘要:

为解决太赫兹频段紧凑型多波束天线结构复杂且制备难度大的问题，提出两种工作于355 GHz频段的太赫兹龙勃透镜天线和部分麦克斯韦鱼眼(PMFE)透镜天线。两种天线均采用周期性金属钉床结构实现梯度折射率表面波透镜，最小特征结构尺寸达60 μm。为调控天线非扫描面波束辐射方向，在两种表面波透镜边缘均加载环形波纹结构；此外，将馈电波导阵列与表面波透镜一体设计，保证天线结构一体性，并采用高精确度(10 μm)3D打印技术一体加工，结合磁控溅射技术完成两种天线表面金属化，实现太赫兹表面波透镜天线低成本可靠制备。仿真结果表明，龙勃透镜天线和PMFE透镜天线在350~360 GHz频段范围内，分别实现±60°和±72°的波束扫描能力。对龙勃透镜天线进行样机加工制造与测试验证，在350~360 GHz频带范围内，表现出良好的阻抗匹配特性和多波束特性：多波束扫描范围为±60°，增益高于16 dBi，波束扫描损耗优于1.2 dB。测试结果与仿真设计结果的吻合性验证了该方案的可行性，为太赫兹多波束天线的设计实现提供了一种崭新的设计思路和技术选择。

Abstract:

To address the issues of complex structure and high fabrication difficulty associated with compact multi-beam antennas in the terahertz frequency band, a terahertz Luneburg lens antenna and a partial Maxwell Fisheye(PMFE) lens antenna operating in the 355 GHz band are proposed. Both antennas use a periodic metallic bed-of-nails structure to realize a gradient refractive index surface wave lens with a minimum structural dimension of 60 μm. To regulate the beam direction in the non-scanning plane, corrugated rings are loaded on the edges of the surface wave lenses. In addition, the waveguide feeding array and the surface wave lens are designed as one piece to ensure structural integrity. High-precision 3D printing(10 μm precision) combined with magnetron sputtering are employed to realize the metallization of two surface wave lenses and low-cost realization of terahertz antenna prototype. The simulated results show the beam scanning capability of ±60° and ±72° for the Luneburg lens antenna and PMFE lens from 350 GHz to 360 GHz, respectively. The Luneburg lens antenna is verified by prototype fabrication and testing, which demonstrates good impedance matching and multibeam scanning performance from 350 GHz to 360 GHz, with a beam scanning range of ±60°, a gain higher than 16 dBi, and a beam-scanning loss better than 1.2 dB. The agreement between the measured and simulated results demonstrates the feasibility of this scheme and provides a new design idea and technology choice for the realization of terahertz multibeam antenna design.