The rapid growth in wireless communication necessitates advanced technologies to meet increasing user demands. Fifth-generation (5G) networks offer substantial advancements over 4G, addressing the need for higher capacity and enhanced performance. A critical component of 5G systems is the design of antennas with wide bandwidth to ensure efficient operation on both network and user sides. This study focuses on developing a triangular microstrip patch antenna using HFSS software, optimized for user-side applications in the frequency band of 28.5 GHz. The antenna was designed on an FR-4 substrate, which has a dielectric constant of 4.4 and a thickness measuring 0.6 mm, demonstrated excellent performance. It achieved a 1.35 GHz bandwidth, a return loss of − 24.07 dB, a realized gain of 5.27 dB, a VSWR of 1.12, and an efficiency of 95.9%, ensuring optimal operation. Compared to prior designs, the proposed antenna demonstrates enhanced capabilities, addressing key challenges for 5G applications.