Defected ground structure antenna array with metasurface inspired interlinked CSRR for 5G millimeter wave...

This paper introduces a high-performance antenna array optimized for 5G millimeter-wave (mm-Wave) applications, efficiently operating within the 25-30 GHz frequency range. Three integrated techniques enhance performance without increasing physical size: First, a Defected Ground Structure (DGS) with a 25 × 25 mm² square slot and embedded interlinked complementary split-ring resonators (CSRRs) inspired by metasurface (MTS) principles broaden bandwidth and improve impedance matching. Second, four oblique slots (4.5 × 0.4 mm²) placed at the ground plane's corners enhance impedance matching, isolation, and extend the upper frequency to 30 GHz. Third, slotted radiation patches optimize radiation gain and efficiency. Initially, the design operated at 26.0-26.5 GHz and 27.5-28.0 GHz with a radiation gain of 2.8 dBi and efficiency of 56%. Incorporating DGS with CSRRs expanded bandwidth to 25-30 GHz, increased average radiation gain to 7.75 dBi, and improved efficiency to 68.75%. Introducing oblique slots further elevated the average gain to 9.15 dBi and efficiency to 79.5%. Finally, integrating open-loop slots into radiating patches raised the average gain to 12.4 dBi and efficiency to 86.25%. The final optimized antenna array, measuring 32 × 32 × 0.8 mm³, demonstrates significant improvements in radiation gain and efficiency, making it a compact, lightweight, cost-effective, and practical solution for 5G and other mm-Wave applications.