Dual Band 28/38 GHz Microstrip Patch Antenna for 5G mmWave applications and the Improvement of antenna operating Bandwidth by applying Defected Ground Structure Technique

Abstract

This study presents the enhancement of a microstrip patch antenna's performance through the Defected Ground Structure (DGS) technique, a method that introduces deliberate modifications to the ground plane geometry. The primary objective is to optimize key performance metrics—such as reflection coefficient, impedance matching, and gain—at two critical millimeter-wave frequencies, 28 GHz and 38 GHz, which are vital for emerging 5G and satellite communication applications. The proposed antenna design was developed using CST Microwave Studio, with the ground plane dimensions meticulously defined as 6 mm × 7 mm × 0.035 mm. Key performance results demonstrate the effectiveness of the DGS approach in achieving superior performance. The reflection coefficient (S11S_ {11}) values at the two operational frequencies were significantly improved, achieving -32.356 dB at 28 GHz and -51.504 dB at 38 GHz. These values indicate excellent impedance matching and minimal power reflection, highlighting the antenna's efficiency in energy transmission. The operational capabilities. Furthermore, the voltage standing wave ratio (VSWR) values were observed to be 1.05 at 28 GHz and 1.06 at 38 GHz, signifying nearly perfect impedance matching across the intended frequency spectrum. In terms of gain, the antenna exhibited a peak gain of 5.875 dB at 28 GHz and 3.74 dB at 38 GHz. These gains are substantial for compact microstrip patch antennas and emphasize the role of the DGS technique in enhancing radiation performance. Additionally, surface current distribution analysis revealed concentrated currents along the patch's edges at both frequencies, providing insights into the antenna's radiation mechanism and the impact of ground plane modifications. The findings validate the DGS technique as a robust method for improving microstrip antenna performance at high frequencies. The optimized design is well-suited for applications in 5G communications, where bandwidth, efficiency, and compactness are critical. By leveraging the DGS approach, this work contributes to the development of advanced antenna designs with enhanced operational characteristics, offering a reliable solution for modern wireless communication systems.