A Butler Matrix Based Multi-Beam W-Band Slot Antenna Array Fabricated by Metal Additive Manufacturing Technology

In this communication, a ridged waveguide (RWG) slot antenna array based on micro-coaxial line (CL) Butler matrix beamforming network (BFN) operating in W-band is proposed. Compared with traditional rectangular waveguide, the employment of RWG decreases the spacing between the adjacent radiators, thereby enhancing the beam-scanning range of the antenna array. Besides, in order to meet the requirements of compact dimensions and precise fabrication, an innovative micro metal additive manufacturing (M-MAM) technology is utilized for antenna fabrication. This technology involves a full-metal process characterized by low loss, ensuring the high-efficiency and high-gain properties of the antenna. During the antenna design using M-MAM technology, fabrication limitations are encountered, resulting in a novel arrangement of the antenna topological structure. The measured results demonstrate that the proposed RWG 4×4 slot antenna array, operating at 100 GHz, achieves a beam-scanning range of ±50° with a maximum gain of 14.5 dBi. The wide beam-scanning range, high operating band, and compact dimensions of the proposed antenna make it suitable for multi-beam applications, providing a novel option for W-band multi-beam antenna.