Application of 3-D metal-direct-printing technique for waveguide antenna fabrication

A novel application of 3-D metal-direct-printing technique is proposed to achieve a highly efficient waveguide-fed antenna. The antenna mainly consists of a 2×2 radiating box-aperture, a matching cavity and a rectangular-to-stepped-waveguide converter, from top to bottom, respectively. In order to avoid the fabrication drawbacks from conventional machining technique, the antenna is 3-D printed in high detailed stainless steel for the purpose of improving antenna efficacy. Experimental results showed that the 3-D printed one compared favorably to one that is fabricated by milling technique. The measured bandwidth with VSWR<;1.5 is 23.7%. High-efficiency of 90% is obtained at 15.0GHz and more than 80% efficiency is maintained over a 2.3GHz bandwidth. This work shows the 3-D metal-direct-printing technique is a promising fabrication method for waveguide-fed antenna structures to achieve desired performance.