Plate-laminated-waveguide corporate-feed slot array antennas with a polarization conversion layer

This paper presents conversion to circular or tilted linear polarization by adding a layer of apertures over the plate-laminated-waveguide corporate-feed slot array antenna. A circularly polarized 16×16-element array antenna achieves high antenna efficiency of 91.6% including losses at 61.5GHz by diffusion bonding of laminated metal thin plates. In a tilted linearly polarized 16×16-element array antenna, the measured cross polarization is -31.5dB in the boresite at the designed frequency of 61.5GHz.