Conformal platform-embedded horn antenna with ultra-wide bandwidth and low profile

This article presents an H-plane horn antenna exhibiting very wide bandwidth, low profile, and nearly end-fire radiation. A wideband coaxial-to-waveguide transition is proposed by employing ridged waveguide and metallic posts in order to enhance the bandwidth and to suppress the higher mode, respectively. An ellipse-shaped copper taper is extended along the horn aperture in order to obtain smooth transition from the aperture to free space. The proposed antenna can be fully embedded in a conducting platform. Simulated results show that the proposed conformal antenna achieves a very wide bandwidth from 3.4 to 18 GHz for VSWR <= 2.5 while retaining the antenna height of only 5.508 mm (0.062 lambda(0) at the lowest operating frequency). Nearly end-fire radiation is obtained over the whole frequency band. The prototype of the conformal configuration with six antenna elements embedded into a large cylindrical platform is fabricated and tested, measured results are in good agreement with simulated ones.