Metasurface-integrated Al₂O₃ ceramic dielectric resonator for enhanced gain and polarization performance in mm-wave MIMO systems

This paper outlines the design and characterization of a dual-port dielectric resonator antenna made from alumina (Al₂O₃) and coupled with a metasurface superstrate for millimeter-wave applications. Alumina ceramic with high permittivity (εr = 9.9, tanδ = 0.0019) was employed to excite the lower-order HEM_11δ mode through aperture coupling to enable efficient radiation between 27.65 and 28.75 GHz. A dual-stub C-shaped slot was carefully engineered on the substrate to generate orthogonal modes, thereby realizing circular polarization throughout the bandwidth of 27.8-28.45 GHz. To access better radiation properties, a double-negative (DNG) metasurface lens made on an RT Duroid substrate was coupled with a resultant increase in realized gain to about 11 dBi, with preservation of impedance and polarization properties. Experimental characterization confirmed steady broadside radiation patterns with low mutual coupling (<- 25 dB), together with exemplary diversity parameters (ECC < 0.02, DG ≈ 10 dB). The integration of both dielectric ceramic and metasurface building materials demonstrates a synergistic building-structure approach to realizing high-gain, circularly polarized, volume-reduced radiators with millimeter-wave applications. These outcomes highlight engineered dielectric-metasurface architectures as a prospective pathway for licensed 5G FR2 frequency band.