Design of Wide-Band Spot Focusing Lens Conical Horn Antenna

Many optical principles can be applied to antenna design. The lens antenna makes use of the function of a lens to refract electromagnetic wave. Lens antennas are widely used in millimeter wave imaging field. The pattern characteristics of lens antenna are good and the requirement of manufacturing accuracy is low. Lens antenna can be divided into dielectric lens antenna and metal lens antenna. The traditional lens antenna transmits electromagnetic wave into plane wave. Spot focusing lens horn antenna, as a dielectric lens antenna, can concentrate electromagnetic wave in a specified area to form a focal spot. This paper proposes a wide band spot focusing lens conical horn antenna. The spot focusing lens horn antenna consists of media lens and conical horn antenna. The structure of the media lens is composed of two convex lenses and a cylindrical structure. The phase center of horn antenna is the position of the focus on one side of the lens. The operating band of the lens horn antenna structure can cover 26.5-40GHz. The measured VSWR is 1.5 Max., the focal length is 270mm Typ., the diameter of the focal spot is 25mm Typ. and the antenna is linear polarization. The proposed antenna can maintain relatively stable performance in a wide frequency band. It proposes a new choice for the measurement system