A large distance focus dielectric Fresnel-based lens antenna for millimeter wave radar

In this paper, we present the design of a focusing dielectric lens, which is based on the concept of a Fresnel step lens. The concept and design of the lens is introduced. Different lenses are surveyed and compared using simulations and measurements with a frequency-modulated continuous-wave (FMCW) radar. The new design shows a smaller focus than the reference focus lens antenna while reducing the size by up to 53 % and the weight of the lens by nearly 48 %. In addition, the Fresnel-based lenses show a frequency dependency, which can be utilized to adjust the focal length.