A High-Gain Tapered Slot Antenna Based on Spoof Surface Plasmon Polaritons Director and Horn-Shaped Dielectric Lens

In this paper, a high-gain tapered slot antenna is proposed by adopting a spoof surface plasmon polaritons (SSPPs) director and a horn-shaped dielectric lens. Firstly, a horn-shaped dielectric lens is designed and connected to the tapered slot antenna. Then, an increment of 0.1-0.9 dBi in the gain of the antenna is obtained in a wide band because of the capacity of the dielectric lens to guide energy in the endfire direction. Moreover, due to the unique property of the confinement of electromagnetic energy in SSPPs structure, a director constituted with the T-shaped SSPPs structure is designed and further integrated into the tapered slot and dielectric lens. Due to the lower equivalent height of the T-shaped SSPPs, the electric field can be more concentrated at the center of the unit rather than at the ends of the branches, resulting in improved antenna directivity. Additionally, compared to traditional antennas equipped solely with SSPPs directors, our proposed antenna, which incorporates both SSPPs directors and horn-shaped dielectric lenses, exhibits a smaller volume increase ratio and a greater gain enhancement ratio. For verification, the finally designed tapered slot antenna operating at 6-18 GHz is fabricated and measured. Experimental results confirm that the designed tapered slot antenna exhibits excellent radiation performance across all frequency bands, achieving a maximum gain as high as 12.3 dBi as well as a maximum gain improvement of 61%, in which radiation patterns show good directivity and endfire radiation performance.