High-efficiency waveguide antenna with 3-D metal-direct-printing technique

Two types of 3-D metal-direct-printing technique are proposed to fabricate complicated waveguide antennas. The 3-D printing technique offers the flexibility to fabricate waveguide structures with complex embedded structures with good reliability and high-precision, which in turn helps to avoid the drawbacks from traditional machining methods when the antenna must be built in separate pieces and secured together. Therefore, waveguide antennas can achieve higher efficiency through this printing technique. Two antenna prototypes have been fabricated in different materials through the two 3-D printing techniques, respectively. Experimental results show that antenna efficiency is higher than 80% over a wide operational bandwidth and even exceeding 90% at most frequencies.