Abstract
A circularly-polarized planar array antenna using hexagonal aperture elements is proposed. A 2×2-element subarray as the basic unit is excited by a corporate-feed circuit located in the lower layer of the double-layered antenna. The hexagonal aperture is designed to achieve a good axial ratio in the boresight. A 16×16-element array antenna with uniform element spacing smaller than the free-space wavelength was fabricated by diffusion bonding of laminated thin metal plates for the 60GHz-band. The high gain of 33.4dBic is measured with 91.6% antenna efficiency, including losses.
