Multibeam High-Gain Ka-Band Polyethylene Lens Antenna for Small Satellite Communication

This paper presents the design of a multibeam lens antenna for the communication system of a small satellite operating in the Ka-band frequency range. Dielectric lens antennas are highly suitable for multi-beam antenna systems in EHF communication satellites, offering advantages such as wide-angle scanning capability and the elimination of feed blockage. The compact nature of CubeSats poses a significant challenge in integrating large antennas required for high-gain performance in specific satellite missions. In the millimeter-wave bands, achieving high gain typically necessitates large apertures, which are difficult to accommodate within CubeSat size constraints. To address this, the proposed lens antenna serves as a compact alternative to conventional horn or reflector antennas, occupying only a 1.1U CubeSat structure with dimensions of 8 × 8 × 11 cm³. This design significantly reduces the required space while maintaining high-gain performance. To ensure thermal stability and structural integrity, Polyethylene with a dielectric constant of 2.3 was chosen as the lens material due to its capability to withstand temperatures ranging from -100°C to 120°C for short durations. Additionally, lens shaping techniques were applied to optimize antenna performance. Two lens geometries plano-convex and concave-convex were investigated to enhance beam focusing and directivity. The proposed design also explores the feasibility of a switched-beam or multibeam antenna system, where multiple primary radiators are strategically positioned around a single lens. Each radiator is aligned along the E-plane to achieve focused beams in specific directions, enabling a wider scanning angle compared to a single-feed configuration. The performance of the shaped lens was evaluated through FEKO simulation software at Ka-band frequencies. Preliminary simulation results demonstrate that the concave-convex lens antenna array achieves a gain of 28.6 dBi with a narrow beamwidth in both the E-plane and H-plane, validating its potential for multibeam operation at defined scanning angles towards the Nadir direction using multiple primary radiators.