Substrate-Integrated E-Plane Waveguide Horn Antenna and Antenna Array

Substrate-integrated waveguide (SIW) is successful to design H-plane horn antenna but fails to design E-plane horn antenna. It is because the plated through holes in SIW only support vertical current but not longitudinal current, both of which are required by the E-plane horn antenna. In this paper, a novel substrate-integrated E-plane waveguide (SIEW) horn antenna is proposed and used to design an E-plane horn antenna array. It radiates electric field parallel to the printed circuit board (PCB) and gives narrow beam in the E-plane and broad beam in the H-plane. The antenna is fabricated by stacking two PCBs with copper strips sandwiched in between. The rows of plated through holes are drilled to support vertical current, and the sandwiched copper strips are used to support longitudinal current. With both the vertical and longitudinal currents on the vertical wall, electric field parallel to the PCB can be guided to the aperture and radiated into the air. A trapezoidal dielectric load is applied to improve impedance matching and gain. An SIEW-to-SMA transition is designed for measurement. For array design, a two-way SIEW power divider is designed based on its equivalent circuit. Both the single antenna element and the antenna array are prototyped and measured.