Millimeter micro-coaxial beam steering array for high-speed satellite communications

Wide-band low-loss passive beam steering array presents to be essential part of the RF front-ends for high-speed detection during deep space exploration missions. In this letter, the copper-based additive manufacturing technology is proposed for the implementation of low-profile (~0.1λ) antenna design. Adopting the micro-coaxial line as the basic design unit enables wide bandwidth design. In addition, the broadband designs of Butler matrix, planar antenna element, and transmission transitions are proposed, respectively. The miniaturization of the metallic patch antenna is realized using a double slotted design, ensuring an array space of ~0.5λ, which beneficial for the low-lobe beam steering. Experimental results show that the antenna array with an overall size of 39 × 29 × 0.5 mm presents four beams located at ±14° and ±43°, respectively. The bandwidth of return loss better than −10 dB ranges from 65 to 71 GHz. The measured result matches well with the simulated ones, which makes its potential operation for satellite applications.