This study is established for designing an Equilateral Triangular Microstrip Patch Antenna (ETMPA) operating at 28GHz suitable for 5G application technologies. The design procedure is performed by considering inset fed techniques and implementing both Computer Simulation Technology (CST) and High Frequency Simulator Structure (HFSS) in order to assess their performance through the computation of antenna parameters. In order to arrive at the aforementioned objectives, different substrate materials with different heights and various conductor patch material types are utilized and their effect on the antenna radiation performance is investigated. The simulation results reveal that a minimum low-profile (ETMPA) of the order of (4.59 mm3) with reliable radiation performances is generally achieved by Taconic-TLX-9 dielectric substrates of height (h=0.2mm) and with copper patch material. Based on the specifications provided above, the results show that the S11, VSWR, efficiency, directivity, gain and bandwidth with both CST and HFSS techniques are, respectively, (-26.24, -14.60), (1.102, 1.53), (81%, 87.6%), (6.31, 6.52) dB, (5.39, 5.94) dB and (0.708 GHz, 0.503 GHz). Besides, a good agreement between the presented optimum antenna parameters is also observed as compared to the ones previously obtained experimentally or theoretically by other researchers for different patch shapes operating at 28 GHz. In addition, the computed results of the antenna parameters display generally that the CST provides better results than HFSS as compared to the ones experimentally obtained by previous researchers. Finally, the proposed antenna design has the advantage of size reduction in comparison to most of the other works and it is one of the 5G technology requirements.