In this study, it is explained how to increase the gain of a two-layer stacked miniaturized microstrip patch antenna (MPA) operating at 5.8 GHz and 10 GHz step by step by combining several different methods used in the literature for performance improvement of MPAs. A commonly used FR4 substrate material was preferred to design and produce the antenna. For electromagnetic modeling of the prototype structure, numerical analysis, and optimization, ANSYS HFSS was used. The performance of the proposed antenna was evaluated in terms of return loss (RL), surface current distribution, radiation patterns and gain/directivity. To confirm the study, the simulation results were compared with the measurements taken over the antenna prototype and good agreement has been achieved. The peak gain values of the proposed antenna at 5.8 GHz and 10 GHz are obtained as 4.11 dBi and 7.15 dBi, respectively.