## 3 Results and Discussion
### Antenna Array with BM Network
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Reference/Antenna (GHz)** & \begin{tabular}{c} **Frequency** \\ **Range** \\ **(GHz)** \\ \end{tabular} & **Bandwidth** & \begin{tabular}{c} **Gain** \\ **(dBi)** \\ \end{tabular} & **Polarization** & \begin{tabular}{c} **Beam** \\ **Steering** \\ \end{tabular} & \begin{tabular}{c} **Primary** \\ **Focus/Application** \\ \end{tabular} & **Notes/Suitability** \\ \hline Proposed (this work) & 5.52–5.99 & 400 MHz & 9.69 & Circular & Yes & \begin{tabular}{c} Underground \\ mining \\ \end{tabular} & \begin{tabular}{c} Enhanced reliability, \\ minimized interference, \\ and robust coverage. \\ \end{tabular} \\ [PERSON], [PERSON], & & & & & & & \\ [PERSON], [PERSON], [PERSON], and and [PERSON] [19] & 2.45 & 200 MHz & 7.50 & Circular & No & \begin{tabular}{c} General \\ communication \\ \end{tabular} & \begin{tabular}{c} Focus on reducing \\ polarization mismatch; no \\ beam steering. \\ Lower design complexity; \\ does not target \\ mining-specific challenges. \\ \end{tabular} \\ [PERSON], [PERSON], & & & & & & & & \\ [PERSON], and [PERSON] [29] & – & (580 MHz) & 8.50 & Linear & No & General & \begin{tabular}{c} Electrically small; suitable \\ for wearable or \\ ultra-compact applications. \\ \end{tabular} \\ [PERSON], & & & & & & & \\ [PERSON], & & & & & & & \\ [PERSON], & & & & & & \\ [PERSON], and & & & & & & & \\ [PERSON] [32] & & & & & & & \\ \cline{3-7} [PERSON], [PERSON], and & & & & & & & & \\ [PERSON] [36] & & & & & & & \\ \cline{3-7} [PERSON], [PERSON], & & & & & & & & \\ [PERSON], and [PERSON] [39] & & & & & & & & \\ [PERSON], [PERSON], & & & & & & & \\ [PERSON], [PERSON], & & & & & & & \\ [PERSON], and [PERSON] [40] & – & 0.38 GHz & 10.70 & Circular & Yes & Mining tunnels & \
\begin{tabular}{c} High design complexity; \\ addresses multipath in \\ confined environments. \\ \end{tabular} \\ [PERSON] and [PERSON] [46] & 0.915 & Narrow & 5.00 & – & – & Localization &
\begin{tabular}{c} RFID-based approach; \\ suitable for tracking in \\ constrained areas. \\ \end{tabular} \\ [PERSON], [PERSON], & & & & & & & \\ [PERSON], and & & & & & & \\ [PERSON] [48] & & & & & & \\ [PERSON], [PERSON], & & & & & & \\ [PERSON], [PERSON], and [PERSON] [49] & & & & & & \\ [PERSON], [PERSON], & & & & & & \\ [PERSON], and [PERSON] [50] & & & & & & \\ \cline{3-7} [PERSON], [PERSON], and & & & & & & \\ [PERSON] [77] & & & & & & \\ \cline{3-7} [PERSON], [PERSON], and & & & & & & & \\ [PERSON] [103] & – & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Performance comparison of designed antenna with existing antennas. such as wearable devices, where low power consumption can extend battery life [107; 108]. The usage of smart antenna systems in underground mines has been demonstrated to improve communication reliability, extend coverage range, and reduce power consumption. This is particularly important for battery-operated devices such as miners' wearable sensors or communication tools, which benefit from extended battery life due to the lower power demands of the system. The beam steering technique provides a generalized solution for various underground applications by reducing signal interference and improving the signal-to-noise ratio, even in complex and dynamic environments like underground tunnels. By directing the antenna's radiation pattern toward specific areas, the communication system becomes more efficient and effective, leading to improved connectivity and operational reliability, as also reported by [109; 110]. However, while the proposed antenna with beam steering characteristics is effective in reducing signal interference, the Butler matrix used provides only four fixed beams on its output, which may limit flexibility compared to more advanced, fully adaptive beamforming technologies that allow for continuous steering across a broader range of angles [111].