This research involves four rectangular patch antenna design, simulation, and optimization at operating frequency of 3.5 GHz. Both designs are used on various substrate materials. CST software is utilized for simulation and optimization purposes. This software is a 3D simulation tool for designing antennas and calculating their many attributes. Reflection coefficient (− 40.37, − 55.81, − 54.7, − 59.58 dB), VSWR (1.019, 1.003, 1.003, 1.002), gain (6.82, 7.06, 3.91, 7.23 dBi), directivity (7.35, 7.52, 6.58, 7.94 dBi), efficiency (92.84, 93.9, 59.4, 91.06%), surface current (24.3, 24.9, 64.4, 23 A/m), and an input impedance (65.16, 50.6, 47.68, 48.2Ω,) is achieved from the simulation results for antenna designs I, II, III, and IV. Besides, the results of four designed simulations are compared. The objective of this study is to enhance the reflection coefficient, standard VSWR, surface current, and impedance matching and to improve antenna gain, directivity, and efficiency. Furthermore, a good level of concordance has been established between the results of the suggested antenna parameters and the findings of previous studies conducted at the same frequency. This proposed antenna is advantageous due to its diminutive size, rendering it suitable for applications in 5G wireless networks because of its compactness.