In this letter, a new structure of a dielectric-loaded substrate integrated waveguide H-plane horn antenna with gradient air slots, fed by a coaxial pin, is proposed. This novel structure aims at improvements in the radiation characteristics, including the gain, front-to-back ratio (FTBR), both E- and H-planes half-power beamwidth (HPBW), and sidelobe level (SLL). The measurements of the fabricated antenna show 15.4 dBi gain, 37 dB FTBR, and narrow E- and H-plane HPBW of 35° and 27° respectively, at 24.15 GHz. The entire antenna structure design is briefly expressed to combine the advantage of one single Rogers TMM4 thermoset laminate layer for reduced manufacturing difficulties and ensured improved performance. The optimized proposed antenna is fabricated by standard printed circuit board (PCB) manufacturing process, with the overall size 61.2 mm × 18.6 mm × 3.175 mm.

中文翻译：

---

具有梯度气隙的介电负载 SIW H 平面喇叭天线

在这封信中，提出了一种新型结构的介电负载基片集成波导 H 面喇叭天线，具有梯度气隙，由同轴针馈电。这种新颖的结构旨在改善辐射特性，包括增益、前后比 (FTBR)、E 和 H 平面半功率波束宽度 (HPBW) 和旁瓣电平 (SLL)。所制造天线的测量结果显示，在 24.15 GHz 时，增益为 15.4 dBi，FTBR 为 37 dB，E 平面和 H 平面 HPBW 分别为 35° 和 27°。整个天线结构设计简明扼要地结合了单个 Rogers TMM4 热固性层压板的优点，以降低制造难度并确保提高性能。优化后的天线采用标准印刷电路板 (PCB) 制造工艺制造，整体尺寸为 61。