## 5 Conclusions  
A circular Minkowski fractal antenna of the second order custom-designed for UWB applications has been presented in this paper. The antenna employs innovative Minkowski fractal geometry, coupled with modifications to the ground plane and microstrip feedline, resulting in substantial performance improvements across the UWB frequency spectrum. The viability of this fractal antenna is established through a comprehensive process encompassing design, simulation, fabrication, and measurement. In simulations, the antenna exhibits an impedance bandwidth of 118%, spanning from 3.17 GHz to 12.44 GHz. In practical measurements, it demonstrates an impressive impedance bandwidth of 120.6%, ranging from 3.37 GHz to 13.6 GHz with a minimum reflection coefficient of \(-40.03\) dB. These characteristics make it a promising candidate for multi-functional wireless applications in the S, C, and X bands. Comparing the simulated and measured results reveals a strong correlation and validation of the antenna's performance through VNA, indicating a VSWR of less than 2 across the frequency range, which further underscores its suitability for practical applications. Additionally, an analysis of the surface current distribution unveils the intricate relationship between the antenna's geometry and its response to different frequencies. These insights shed light on radiation patterns and provide valuable data for future optimizations. In conclusion, the antenna parameters affirm that the designed and developed circular Minkowski fractal antenna has proven its worth as a promising choice for UWB applications.  
Conceptualization, E.J., P.K. and T.A.; methodology. E.J., P.K. and T.A.; software, E.J.; validation, E.J., P.K. and T.A.; Writing--E.J. and P.K.; Writing--review and editing, E.J., P.K. and T.A.; supervision, P.K. and T.A. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
**Data Availability Statement:** Not applicable.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Ref.** & **Substrate** & **Size (mm 3)** & **Resonant Frequency (GHz)** & **Bandwidth (GHz)** & **Gain (dB)** & **Dielectric Constant** \\ \hline
[22] & FR-4 & \(30\times 30\times 1.6\) & 8.2 & 3.1– 11.7 & 3.9 & 4.4 \\ \hline
[23] & FR-4 & \(30\times 30\times 1.6\) & 4.2, 9.9 & 3.4–12 & 4.6 & 4.4 \\ \hline
[24] & FR-4 & \(35\times 30\times 1.6\) & 4.5, 6.5,9.5 & 3–3.22, 3.97–4.94, 5.84–7.25, 7.86-11 & 4.3 & 4.4 \\ \hline
[25] & FR-4 & \(23.9\times 23.9\times 1.405\) & 5.2 & 3.2–5.34 & 2.76 & 4.4 \\ \hline
[26] & FR-4 & \(30\times 30\times 1.6\) & 2.1, 2.4, 2.7, 4.4, 14.5 & 2.34–2.47, 4–18 & 4.4 & 4.3 \\ \hline
[27] & FR-4 & \(32\times 32\times 1.6\) & 5.5 & 1.4–9.6 & 3.8 & 4.4 \\ \hline
[28] & FR-4 & \(87.5\times 61\times 1.6\) & 2.5, 3.8, 5.3 & 1.8–2.9, 3.4–4.6, 5–5.6 & 3.34 & 4.4 \\ \hline
[29] & Roggers RT/5880 & \(24\times 30\times 0.787\) & 4,8,12 & 3–12.7 & 3.6 & 2.2 \\ \hline
[30] & Roggers RT/5880 & \(30\times 24\times 0.8\) & 4.02, 8.11, 11.85, 15.86 & 3–17.2 & 5.6 & - \\ \hline This work & FR-4 & \(28\times 28\times 1.6\) & 4.06, 9.7, 11.48 & 3.37–13.6 & 6.24 & 4.4 \\ \hline \hline \end{tabular} Note: Ref= Reference, - = not reported.  
\end{table}
Table 3: Comparison of the designed UWB CMFA with the existing antennas in the literature.