Design and Performance Analysis of a Dual-Band Microstrip PatchAntenna with Defected Ground and U-Slot Loading for Sub-6 GHz 5GApplications

Introduction: This study reports the design evolution and performance analysis of a compact dual-band microstrip patch antenna (MPA) for Sub-6 GHz 5G wireless systems. The key objective is to achieve a wide -10 dB impedance bandwidth while maintaining the antenna's physical size, which is a critical constraint in compact antenna design. Methods: The MPA is realized through a four-stage design methodology, commencing with a conventional inset-fed rectangular substrate. In the subsequent steps, a defected ground structure (DGS) and dual inverted U-slots are incorporated to modify the surface current distribution. The proposed MPA is designed on a cost-effective FR-4 epoxy substrate, and its geometrical parameters are optimized using a Genetic Algorithm (GA) to improve impedance bandwidth. Results: The final optimized MPA exhibits two resonant bands with bandwidths of 590 MHz at 3.76 GHz and 180 MHz at 4.66 GHz, covering the n77 and n78 5G NR frequency bands. A minimum return loss (S11) of −44.7 dB and a VSWR of 1.011 are achieved at the resonance frequency. The MPA demonstrates a simulated gain of 3.17 dB, directivity of 4.74 dB, and radiation efficiency of 64.54%. Discussion: Compared to a conventional patch antenna, the proposed MPA provides nearly five times the bandwidth while maintaining its physical size and stable radiation characteristics across the targeted frequency bands. Conclusion: With compact dimensions of 30.9 × 28.8 × 1.6 mm3, the optimized MPA is suitable for Sub-6 GHz 5G, Wi-Fi, IoT, and next-generation wireless applications.