The Luneburg lens, often incorrectly spelled Luneberg lens, is a type of dielectric lens that collects and focuses electromagnetic energy. Based on a theory proposed by Rudolf Karl Luneburg in 1944, the lens is spherical in shape where the dielectric constant varies more largely in sections nearer to its center. Due to this property, the lens can refract and focus the energy incidence. When the angle of incidence varies, the focal point also varies. Characteristically, it can focus energy that enters from all angles due to its spherical shape.
Applications of the lens include satellite antennas, weather radar antennas and electromagnetic wave measuring devices.