Metasurface-Integrated Patch Antennas: Radiation Characteristics Enhancement Validated Across Multiple Patch Antenna Topologies

This paper presents a versatile metasurface (MS) structure for enhancing the radiation performance of multiple microstrip patch antenna topologies operating in the 5.8 GHz ISM band. Unlike conventional metasurface-assisted antenna designs that are optimized for a single radiator, the proposed MS is systematically integrated with four fundamentally different antenna configurations, including a conventional rectangular patch antenna, an ultra-wideband (UWB) patch antenna, a 1 × 4 corporate-fed patch array, and a coplanar MS-loaded 1 × 4 array, thereby demonstrating its applicability across diverse antenna architectures. The electromagnetic characteristics of the proposed unit cell are first investigated through full-wave simulations and constitutive-parameter retrieval, revealing resonant magnetic behavior, strong reflective characteristics, and a negative refractive index region around the operating frequency. The metasurface is subsequently employed as either a reflective superstrate or an in-plane loading structure to manipulate the radiated wavefront, improve aperture utilization, and enhance radiation directivity. Across the antenna configurations investigated, realized gain improvements ranging from 1.0 to 6.3 dB are achieved without significant degradation of impedance matching, corresponding to relative improvements between 8.3% and 315%. The highest realized gain of 15.7 dBi is obtained for the superstrate-loaded 1 × 4 array, while the coplanar-loaded array achieves 14.3 dBi with half-power beamwidths of approximately 17° and 37° in the principal planes. Prototype fabrication and experimental characterization demonstrate good agreement with full-wave simulations, confirming the effectiveness and robustness of the proposed metasurface. The presented approach establishes a practical and scalable metasurface platform for improving the radiation characteristics of different patch antenna topologies, making it attractive for high-performance wireless communication, radar, sensing, and emerging microwave systems.