Compact Multibeam High-Gain Ka-Band Polyethylene Lens Antenna Design for SmallSat Applications

This paper presents a compact multibeam dielectric lens antenna designed for small satellite communication in the Ka-band. Conventional horn and reflector antennas require large apertures to achieve high gain, which are impractical for CubeSat missions with strict payload limitations. The proposed antenna provides a compact solution, occupying only a 1.1U structure (8 × 8 × 11 cm³), while supporting wide-angle scanning and reducing feed blockage. Polyethylene, with a dielectric constant of 2.3, was selected as the lens material due to its stability and ability to withstand temperatures from -100 °C to 120 °C. Two lens geometries plano-convex and concave-convex were investigated to improve directivity and beamforming. Multibeam capability is realized by arranging multiple feed sources along the E-plane, enabling beam-switching in different directions. FEKO simulations show that the concave-convex design achieves a gain of 28.6 dBi with narrow beamwidths in both the E- and H-planes, while the plano-convex design offers wider scanning angles and better sidelobe suppression. For comparison, a single pyramidal horn at 36 GHz achieves only ~9 dBi peak gain, whereas the horn with lens increases the gain greater than 28 dBi. These results confirm the feasibility of using shaped dielectric lenses to create compact, high-performance antennas suitable for small satellite applications.