## 3 Performance Evaluation with ORAN Testbed  
To evaluate the performance of the proposed antenna in a real-world scenario, a proof-of-concept testbed of a private 5G network based on ORAN split option 7.2 is implemented. Different components of the 5G network with the proposed antenna are illustrated in Figure 11. ACES in-house builds the radio frequency front end. For O-RU services, we utilized a commercially available, off-the-shelf SDR Ettus USRP B200. The srsRAN open-source software radio suite is installed on Ubuntu 22.04 for O-CU/O-DU services [30].  
Figure 10: MIMO Diversity parameters. (**a**) Left Y-Axis is Envelope Correlation Coefficient and Right Y-Axis is Total Active Reflection Coefficient. (**b**) Left Y-Axis is Diversity Gain and Right Y-Axis is Channel Capacity Loss.  
The metamaterial superstrate significantly enhanced both downlink and uplink throughput stability, maintaining consistent downlink throughput of approximately 200 Mbps and uplink throughput of nearly 70 Mbps throughout the 24 h period. In contrast, the antenna without MTM exhibited considerable throughput fluctuations, with dramatic drops of up to 30 Mbps in downlink and 25 Mbps in the uplink during peak usage hours (8:00-20:00), demonstrating the MTM design's superior resilience to network congestion as depicted in Figure 12a. From Figure 12b, the implementation of the metamaterial resulted in a consistent 25-30 ms increase in transmission latency across all times, attributable to the additional signal processing complexity within the MTM structure. However, this design choice significantly reduced jitter by approximately 10 ms compared to the conventional antenna, demonstrating that the metamaterial superstrate effectively stabilizes signal propagation at the expense of slightly higher transmission delay.  
A walk test was conducted in a designated indoor scenario to evaluate the performance of reference signal received power (RSRP) using INOS Digis Wireless RF processing tools, with the testing setup positioned in front of the exit door as indicated in the building's floor plan in Figure 13. The results demonstrated robust signal coverage, with an excellent RSRP of more than \(-75\) dBm observed across over 75% of the coverage area, ensuring strong signal quality for the majority of the space. Additionally, a good RSRP level exceeding \(-85\) dBm was recorded in approximately 24% of the area, further highlighting the effectiveness of the setup. The signal strength distribution, ranging from \(-120\) dBm to  
Figure 11: ORAN-based Private 5G testbed for a real-world testing scenario.  
Figure 12: Performance comparison of antenna designs with and without metamaterial over a 24-h period. (**a**) Throughput Downlink, Uplink and (**b**) Transmission delay Latency, Jitter.  
\(-\)75 dBm, was mapped across the floor plan, providing a comprehensive overview of the wireless performance in this indoor environment.  
Table 5 presents a comparative analysis of the proposed MIMO antenna against previously reported state-of-the-art MIMO antennas operating in the sub-6 GHz band, evaluating parameters such as overall antenna profile, peak gain, port isolation, substrate material, techniques employed to enhance isolation, envelope correlation coefficients, and real-world proof-of-concept validation.