Dielectric-Loaded SIW H-Plane Horn Antenna With Gradient Air Slots

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.