A topology optimization method for designing dielectric microstructures in low-profile and lightweight phased antennas with enhanced scanning capabilities

Stacked phased array antennas play a vital role in modern radar and communication systems due to their capability for wideband and wide-angle beam scanning. However, their application is limited by the fixed dielectric properties of conventional substrates, which restrict bandwidth, scanning performance, and miniaturization. To address this critical challenge, this paper proposes a novel design method that combines topology optimization with 3D printing to generate substrate microstructures with customized dielectric properties. The proposed method includes (1) performance-driven optimization to determine the desired dielectric properties and (2) a topology optimization method based on scattering parameter inversion to realize these properties in manufacturable dielectric structures. A stacked phased array antenna operating in the X-band (8–12 GHz) is designed and fabricated to validate the proposed method. The designed antenna achieves a VSWR < 2 impedance-matching bandwidth covering 8–12 GHz in the normal direction, and maintains VSWR < 2.5 across the same frequency range when scanning up to ± 45° in both the E- and H-planes. In addition, the designed antenna reduces overall weight by 27.5 % while maintaining a low profile of only 8.624 mm. This paper demonstrates a promising pathway to enable the next generation of low-profile, lightweight, and high-performance phased array antennas.