High-Efficiency, Low-Cost, Wideband AFTSAs for W-Band and D-Band High-Resolution Imaging

This letter presents a W-band antipodal Fermi tapered slot antenna (AFTSA) with 37.8% relative bandwidth and introduces a novel antipodal fin-line waveguide-to-microstrip transition for feeding. Featuring a lightweight design, each AFTSA weighs only 0.23 g. The transition achieves a return loss better than 15.7 dB and an insertion loss below 0.63 dB. Measurements of five AFTSAs fed by this transition show efficiencies exceeding 80% at most frequency points, with gains ranging from 15 to 20 dB across the W-band. At the target frequency of 100 GHz, the gain is approximately 18.7 dB, the efficiency reaches 88%, and the half-power beamwidths are 1–3° wider than the simulated values of 17.0°/22.8° (E/H). The measurements show favorable agreement with the simulations. Additionally, an array of eight AFTSAs is integrated on a single RO3003 substrate, and a D-band AFTSA design is also presented.