## 3 Results and Discussion
### SAR Analysis  
Preliminary results of the SAR analysis for the proposed antenna design near human tissue are a significant factor for determining the safety and performance of the proposed antennas. In the proposed MIMO antenna system, the SAR values were analyzed under two scenarios: There were two types examined, namely, hand simulation and head  
Figure 12: Envelope correlation coefficient of proposed multi-port MIMO antenna array. (**a**) Simulated reflection coefficient. (**b**) Measured reflection coefficient. (**c**) Reflection coefficient with hand. (**d**) Reflection coefficient with head.  
Figure 13: Diversity gain of a proposed MIMO antenna array throughout the obtained frequency band.  
simulation. In the case of hand simulation for a 1-g tissue, the maximum and minimum SAR values were found to be 0.118 W/kg and 0.0606 W/kg, respectively, as shown in Figure 14. Likewise for a head simulation of a 10-g tissue, the maximum and minimum SAR values reported were 18.7 W/kg and 1.72 W/kg, as shown in Figure 15. These results confirm that the system's radiation level is within SAR regulatory limits and prove that the system can safely function in typical environments. The low SAR values demonstrated in the hand simulations thus confirm the antenna's appropriateness for handheld devices, while the performance observed in the head simulations shows its application in smartphones. In realizing low SAR values and sustaining good efficiency and isolation of the antennas, the presented design provides safety for users and effectiveness for future wireless communications.  
Recent research on MIMO antennas for 5G smartphones has placed significant emphasis on SAR (specific absorption rate) assessment to ensure both high-performance connectivity and user safety. The study \"High Performance Eight-Port Dual-Band MIMO Antenna System for 5G Devices\" [36] explored an eight-port antenna system, optimizing isolation to achieve lower SAR values while maintaining reliable performance. Similarly, \"SAR Assessment of Miniaturized Wideband MIMO Antenna Structure for Millimeter Wave 5G Smartphones\" [37] focused on the impact of compact MIMO designs operating at millimeter-wave frequencies, ensuring that device miniaturization did not compromise safety compliance. The research \"Dual-Band Ten-Element MIMO Array Based on Dual-Mode IFAs for 5G Terminal Applications\" [26] evaluated SAR levels for a ten-element  
Figure 14: SAR values of proposed multi-port MIMO antennas for hand simulation.  
Figure 15: SAR values of proposed multi-port MIMO antennas for head simulation.  
MIMO array, demonstrating an effective balance between radiation efficiency and user exposure limits. Likewise, \"High-Isolation Eight-Element MIMO Array for 5G Smartphone Applications\" [38] examined isolation techniques and their role in reducing the SAR, ensuring compliance with safety regulations while enhancing antenna performance. These studies align with our research, as we also focus on SAR optimization through strategic antenna placement, decoupling techniques, and miniaturization. Our findings contribute to this ongoing research by offering a comprehensive evaluation of SAR mitigation strategies in modern MIMO antenna designs for 5G smartphones.