High-Gain 3D-Printed Dual-Reflector Antenna for Millimeter-Wave Applications

5G communication is characterized by a broad bandwidth, enabling a peak information transmission capacity of up to 20 Gbit/s under ideal conditions. In order to achieve this goal, millimeter-wave antennas are utilized. However, classical parabolic reflectors often suffer from limited effective aperture due to manufacturing constraints, which restrict their achievable gain. To enhance gain while maintaining a compact form factor, in this paper, a dual-reflector antenna is adopted. By tilting the main radiation direction of the feed antenna in the Cassegrain configuration, the sub-reflector and main reflector are truncated with reference to the ray-tracing coverage area. This design can not only suppress the blockage effect existing in traditional Cassegrain antennas but also improve the effective radiation performance of the main reflector. Moreover, since substrate-integrated waveguide (SIW) is well suited for millimeter-wave applications, a planar SIW-fed Yagi-Uda antenna array is synthesized as the feed. The fabrication of such a dual reflector is inherently complex. However, the combination of 3D printing and metal coating using vacuum deposition creates a simple and efficient manufacturing process. Experimental results demonstrate that the proposed antenna achieves a gain of 27 dBi over 57–64 GHz with a stable pointing of the main beam direction across the operating band.