A 3D-Printed Compact High-Efficiency Magneto-Electric Dipole Antenna Sub-Array for Millimeter-Wave Multi-Beam Applications

A novel three-dimensional (3D) printed 2 × 2 multi-beam magneto-electric (ME) dipole antenna subarray with a metallic configuration is investigated in the Ka-band. A modified topology of the beamforming network consisting of four air-filled 3-dB couplers is proposed, whose miniaturized size in the horizontal plane is equal to the radiating aperture of the subarray. By combining the beamforming network with the 3D printed waveguide-fed ME-dipoles, the two-dimensional multi-beam subarray is designed, printed and tested. A wide impedance bandwidth of 20%, four stable tilted radiation beams with almost identical radiation patterns in the two orthogonal planes, high radiation efficiency of 87% and high gain performance are achieved successfully. The millimeter-wave subarray-level beam-scanning array with a large size can be implemented based on the presented design. With the compact geometry fabricated in a whole piece and the good operating characteristics, this work is valuable to the emerging millimeter-wave multiple-input multiple-output (MIMO) applications.