基于Vivaldi的超宽带低剖面天线设计

Design of ultra-wideband low-profile antenna based on Vivaldi

针对超宽带小型化雷达系统的需求背景,设计了一款通过交趾耦合形成天线间紧耦合结构的超宽带低剖面阵列天线。该阵列天线单元首先在传统Vivaldi天线结构上增设了一对带圆形腔体的弧形槽,从而使传统Vivaldi天线顶端呈现类似偶极子辐射结构的形态;然后通过采用交趾耦合结构起到天线间紧耦合作用,明显降低了天线的整体剖面高度;接下来在天线单元上层引入介质匹配层,进一步改善了匹配效果。仿真结果表明:设计的阵列天线在2.5~15 GHz工作频段内,其驻波比均小于2,12×12天线阵列最大增益大于20 dB,阵列天线单元剖面高度仅为15 mm(0.125倍低频波长)。因此,设计的天线在保证超宽带性能下还大大降低了天线的剖面高度,具有较高的工程应用价值。

In response to the demand for miniaturized ultra-wideband radar systems,a novel ultra-wideband low-profile antenna array is designed with close coupling between antenna elements achieved through a cross-coupling structure.The proposed array antenna unit enhances the traditional Vivaldi antenna structure by introducing a pair of arc-shaped slots with circular cavities,giving it a dipole-like radiation pattern at the top of the Vivaldi antenna.The cross-coupling structure is employed to achieve tight coupling between the antenna elements,significantly reducing the overall profile height of the antenna.Additionally,a dielectric matching layer is introduced on top of the antenna unit to further improve the matching performance.Simulation results demonstrate that the designed array antenna exhibits a standing wave ratio of less than 2 across the 2.6 GHz to 15 GHz frequency range.The maximum gain of the 12×12 antenna array exceeds 20 dB,while the profile height of the array antenna unit is merely 15 mm(0.125 times the low-frequency wavelength).Hence,this antenna design not only meets the requirements of ultra-wideband performance but also greatly reduces the profile height of the antenna,offering significant engineering applications.