# Slotted Circular-Patch MIMO Antenna for 5G Applications at Sub-6 GHz
## 5 Experimental Testing of the Proposed Antennas Within the 5G MIMO Application Framework  
The MIMO Application Framework (LabVIEW Communications) provides licensed software for a customizable real-time MIMO reference design relevant to the LTE standard. This MIMO Application Framework features an FPGA-based software reference design that supports a fully streaming, real-time physical layer for both uplink and downlink at 20 MHz TDD, adhering to the LTE standard. The three proposed fabricated antennas were implemented and experimentally tested using the MIMO Application Framework for 5G systems, which operates in the sub-6 GHz range. The testing took place at the Next Generation Wireless Communication Technologies Laboratory for Smart Cities at the Egypt-Japan University of Science and Technology. The MIMO Application Framework comprises two primary components: the multi-antenna mobile station (MS) and the multi-antenna base station (BS). Both the multi-antenna BS and the multi-antenna MS represent the most complex system elements supported by the MIMO Application Framework. The base station includes a PXIe-8135 controller and can accommodate between one and eight PXIe-8384 MXI-Express modules for communication with USRP devices. It also supports up to five PXIe-7976 modules, depending on the number of USRP subsystems installed in a PXIe-1085 chassis. The mobile station supports an even number of antennas, ranging from two to twelve. A multi-antenna MS uses the same general hardware setup as a 16-antenna BS. The number of USRP devices, which serve as remote radio heads (RRHs), can be lower and is determined by the number of antennas, with two antennas supported for each USRP device. Three antennas are connected indoors to the BS and MS ports. Subsequently, a computer is connected to the USRP antenna via a USB cable, while an Ethernet cable links the system to a router for Internet access. Figure 27 presents the implementation of MIMO of two 1 \(\times\) 4 arrays, MIMO of two 1 \(\times\) 2 arrays, and a single element on the 5G MIMO Application Framework, respectively. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref.** & **Size** & **Bandwidth** & **Gain** & **ECC** & **Substrate Material** &
\begin{tabular}{c} **Max** \\ **Efficiency \%** \\ \end{tabular} & **Application** & **Technique** \\ \hline
[21] & \(180\times 180\times 2.7\) & 1.68–4.15 & 8.4–9.4 & 0.0005 & Fr-4 & - & 5G & M-shape strip \\ \hline
[22] & \(150\times 150\times 10\) & 3.3–5 & 5.2–6.8 & \textless{}0.05 & Fr-4 & 84 & 5G & Annular-ring \\ \hline
[23] & \(129.5\times 129.5\times 28.2\) & 1.55–6 & 4–10 & \textless{}0.5 & - & 84 & 5G & Cavity-backed \\ \hline
[24] & \(157\times 96\times 1.53\) & 2.4–2.5 & 8 & 0.004 & Fr-4 & - & WLAN & Tapered Stub \\ \hline
[25] & \(110\times 110\times 0.8\) & 3.12–3.9 & 7.3 & 0.3 & ROGER RT Duriod & 90 & 5G & Cylindrical DRA \\ \hline
[26] & \(190.5\times 190.5\times 33\) & 1.27–6 & 4–11 & \textless{}0.1 & R04003C & 82 & WIFI & MIMO \\ \hline
[28] & \(110\times 110\times 0.787\) & 3–5.5 & 5.2–7.8 & - & Fr-4 & - & 5G &
\begin{tabular}{c} Phased array \\ antenna \\ \end{tabular} \\ \hline
[40] & \(135\times 135\times 0.1\) & 3.92–5.05 & 3.7 & \textless{}0.05 & \
\begin{tabular}{c} Polyethylene \\ terephthalate (PET) \\ \end{tabular} & 74 & 5G & Cavity-backed \\ \hline Proposed & & 2.33–4.02 & & & & & \\ MIMO of & \(140\times 132\times 1.57\) & 4.25–4.4 & 8–10.9 & \textless{}0.003 & RTS880 & 97.46 &
\begin{tabular}{c} 5G/Sub- \\ 6 GHz \\ \end{tabular} & MIMO-array \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Comparison of the proposed MIMO of two \(1\times 4\) arrays design with previous studies. Figure 27: MIMO application framework implementation for: (**a**) MIMO of two 1 \(\times\) 4 arrays, (**b**) MIMO of two 1 \(\times\) 2 arrays, (**c**) Single element. Once the system is established, the three antennas are connected to the USRP, configured, compiled, and executed. Finally, mobile phones are connected to the cellular networks.