摘要： This paper presents a Luneburg lens and a Luneburg reflector-lens along with the corresponding compact and cost-effective multibeam antennas in the Ka-band. The Luneburg lens is composed of an air-filled parallel plate waveguide (PPW) loaded with equal-sized metallic posts. The upper plate of the PPW is designed to a curved surface to meet the requirement of the equivalent refractive index profile, meanwhile providing a transition between the lens and the feed waveguide. Also, based on the law of reflection, a reflecting wall is introduced to the Luneburg lens to achieve a Luneburg reflector-lens. By employing the WR28 rectangular waveguides as the feeders, the Luneburg lens/reflector-lens antennas with single beam and multiple beams are designed and experimentally verified in the whole Ka-band. The multibeam Luneburg lens antenna show the beam scanning from -45° to +45° with 0.6 dB scan loss. The multibeam Luneburg reflector-lens antenna show the beam scanning from 30° to 60° with 0.7 dB scan loss. Besides, the acceptable performances of aperture efficiency, impedance matching and multi-port isolation are achieved. The results indicate that the works in this paper have application potential in the millimeter-wave (mmW) wireless communications.