60 GHz band 2×4 dipole array antenna using multi stacked organic substrates structure

Wireless systems using license-free 60 GHz band have been focused as Gbps ultra-high speed data rate short range communication. Beamforming techniques based on array antennas have been employed to obtain high directional antenna gain. In order to realize an array antenna in millimeter-wave frequency range, the accuracy of positioning of the antenna elements becomes considerably important. Conventional 60 GHz band beamforming antennas have used a patch array antenna configuration. Since the patch antenna is patterned on a substrate, high accuracy of the positioning is obtained. These patch array antennas realize a main beam in the vertical direction of the substrate. In order to realize a main beam in the horizontal direction of the substrate, 1×4 dipole array antenna was developed and beam scanning in the azimuth plane was possible. For 2-dimensional (azimuth/elevation) beam scanning, 3×2 vivaldi array antenna using multi-layered substrate was reported. It showed the 2-dimensional beam scanning function, but a high antenna gain could not be obtained. Since the antenna elements were fabricated in a multi-layered substrate, the antenna elements were placed very close (nearly 1/25 λ₀) in elevation direction and it caused relatively low antenna gain.