# Higher-Order-Mode Triple Band Circularly Polarized Rectangular Dielectric Resonator Antenna
## 4 Conclusions  
In summary, the proposed CP DRA with a microstrip patch coupled to the double stub feed structure could generate a tri-band CP antenna. The comparison was made to previous works on CP DRA, where it can conclude that the proposed CP DRA outperforms in terms of gain and the operational bandwidth by simple feeding structure. The combination of fundamental and higher-order mode excitation helps in enhancing the gain and bandwidth of the antenna. A bandwidth of 48% with a gain above 6 dBic was achieved in all resonance frequencies.  
Conceptualization, M.N.M.Y. and I.A.; methodology, M.N.M.Y.; software, M.N.M.Y.; validation, M.F.Z., J.I. and M.N.O.; formal analysis, I.A.; investigation, M.F.Z.; resources, M.F.Z.; writing--original draft preparation, L.A. and M.N.M.Y.; writing--review and editing, I.A. and M.N.O.; visualization, I.A.; supervision, J.I.; project administration, M.N.O.; funding acquisition, M.F.Z. and M.N.M.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by UNIVERSITI MALAYSIA PERLIS and Ministry of Higher Education, grant number FRGS/1/2020/ICT09/UNIMAP/02/2.  
**Informed Consent Statement**: Not applicable.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Ref No.** & \multicolumn{3}{c}{**Impedance BWs (GHz) (\%)**} & \multicolumn{3}{c}{**3 dB AR BWs (GHz) (\%)**} & \multicolumn{3}{c}{**Peak Gain (dBic)**} & \multicolumn{3}{c}{**Size (\(\lambda_{\text{o}}\))**} \\ \hline
[3] & 1.71–2.03 & 2.23–2.96 & 3.65–3.76 & 1.86–1.93 & 2.67–2.82 & 3.68–3.78 & 5 & 5.28 & 2.36 & 0.44 \(\times\) 0.5 \(\times\) 0.16 \\ \hline
[5] & 1.45–1.87 & 2.13–0 & - & 1.53–1.63 & 2.4–2.49 & - & 6.1 & 8.49 & - & - \\  & [25.3] & [35.3] & & [6.3] & [3.68] & & & & & \\ \hline
[6] & 1.77–2.0 & 2.38–2.96 & - & 1.76–1.94 & 2.39–2.92 & - & 5.5 & 6.0 & - & - \\  & [12.2] & [21.7] & & [9.7] & [20] & & & & & \\ \hline
[10] & 1.92–1.96 & 2.32–2.50 & 3.42–3.55 & 1.93–1.96 & 2.36–2.48 & 3.50–3.53 & 1.2 & 1.6 & \(-1.5\) & 0.32 \(\times\) 0.32 \(\times\) 0.15 \\  & [1.55] & [7.68] & [3.87] & [1.55] & [4.96] & [0.8] & & & & \\ \hline
[16] & 2.12–2.45 & 2.64–3.98 & - & 2.29–2.44 & 2.76–2.95 & 3.67–3.94 & 4.5 & 5.38 & 5.75 & - \\  & [14.4] & [40.5] & & [6.34] & [6.65] & [7.09] & & & & \\ \hline
[17] & 3.4–3.58 & 5.1–5.9 & - & 3.46–3.54 & 5.18–5.34 & - & 5.1 & 5.15 & - & 0.47 \(\times\) 0.47 \(\times\) 0.11 \\  & [5.16] & [14.55] & - & 3.18–3.29 & 4.88–5.18 & 5.28–5.45 & 6.2 & 9.44 & 9.3 & 0.3 \(\times\) 0.29 \(\times\) 0.16 \\ \hline Proposed & 2.43–4.35 & 4.82–5.61 & - & 3.18–3.29 & 4.88–5.18 & 5.28–5.45 & 6.2 & 9.44 & 9.3 & 0.3 \(\times\) 0.29 \(\times\) 0.16 \\  & [48] & [14.8] & - & [3] & [4.5] & [3.18] & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of the previous works with the proposed DRA.  
Figure 16: Simulated and measured radiation patterns of the proposed DRA.  
**Acknowledgments: Authors would also like to thank all researchers of Antenna Research Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia specifically [PERSON] for his great assistance during measurement for supporting this project.**  
**Conflicts of Interest: The authors declare no conflict of interest.**