Sub-THz Silicon-Micromachined Reconfigurable Beam-Steering Frontend

This paper presents a reconfigurable silicon micromachined beam-steering antenna frontend. The antenna frontend consists of multiple components that are integrated within a single chip with a total size of 14.3x20x1.2 mm(3). The signal path includes a novel switching circuit for beam-shape switching, a magic-tee, a delay network for beam-steering, two power-dividing networks for sidelobe level (SLL) reduction, and a 2x8 antenna array. The implemented antenna frontend can radiate two frequency steerable beam-shapes, in which the switching circuit determines the radiated pattern. The first beam-shape is a broad beam, and the second is a notched beam. According to the required specifications, both radiation patterns can be steered by the operating frequency in the E-plane and move from -20 degrees at 238 GHz to +20 degrees at 248 GHz. The SLL is reduced in the H-plane with the measured SLL of better than 18.5 dB for the broad beam in the entire sweeping range. The measured notch depth is better than 24 dB in the entire sweeping range. The measured return loss of the fabricated device is better than 15 dB between 220 and 265 GHz, which is equal to 18.6% of fractional bandwidth.