Electrically-small Luneburg lens for antenna gain enhancement using new 3D printing filling technique

Abstract This paper presents a low-cost multi-layered electrically-small dielectric lens for improving the maximum radiation gain and side-lobe-level (SLL) for a directive antenna such as a horn antenna utilizing a new additive manufacturing filling technique. For obtaining the best performance of such a lens, the variation of the dielectric constant of outer layers toward the inner layers should be smooth and continuous while the transition should happen fast for smaller physical dimensions. Since it will be very difficult and expensive to fabricate such a lens, the multi-layer stepped configuration becomes more practical and desirable. Instead of using different materials for different layers, the same material is used but with different densities. Therefore, the total size, fabrication cost, and complexity are reduced significantly. The gain of an open waveguide at 10 GHz is increased by 15 dB while SLL is kept below −15 dB using the proposed spherical dielectric lens. In addition, 59.26% aperture efficiency with 20.5 dBi total gain is achieved.