Millimeter wave orthogonally polarized substrate integrated waveguide slot antenna arrays

Substrate integrated waveguide (SIW) antenna array design with orthogonal polarizations with respect to the array axis is proposed. The antenna structure consists of three layers containing a feeding network, cavities and dielectric cover. The proposed design can achieve any desired polarization and it can be used to design two dimensional arrays. Two 10 element arrays are fabricated with polarization parallel and orthogonal to the array axis. These arrays provide 1GHz impedance bandwidth in automotive radar frequency range (76-81GHz). The designed beamwidth is 9° in the plane parallel to the array axis and 120° in the perpendicular plane. Approximately 20dB cross polarization rejection is measured in the desired field of view. The matched measured and simulated results show the validity of the proposed design.