Wideband printed Fresnel reflector antenna in W-band

Millimeter wave radar becomes has been increasingly used in the defense sector and civil applications like automotive cruise control or helicopter crash avoidance. Parallel to this development, antennas have to support an increasing number of functions that can be provided by the augmentation of their bandwidth or multiband operating modes. Although wideband and multiband single printed antennas are now more developed, millimeter wave wideband arrays remain limited because of their complexity and metallic losses. In this paper, The authors present a printed millimeter wave reflector using circular patches centered at 94 GHz suitable for radar applications whose elements and primary source have been designed to achieve about 9 % bandwidth in terms of reflection coefficient and gain.