# A Miniaturized RHCP Slot Antenna for Wideband Applications Including Sub-6 GHz 5G
## 7 Conclusions  
A new wide-slot antenna has been designed to achieve wideband circular polarization with satisfactory axial ratio and impedance bandwidth while maintaining a compact antenna footprint. The proposed antenna has been fabricated and tested in this paper. This antenna consists of a microstrip line-fed tuning stub, slotted ground plane, strips, and stubs that are added to achieve a wide range of impedance BW and ARBW. This antenna generates CP in the broadside direction and radiates waves with broadband RHCP. The overall size of the presented antenna is 0.39\(\lambda\)\(\times\) 0.36\(\lambda\)\(\times\) 0.011\(\lambda\). The measured \(-10\) dB impedance BW is 78% along the range (2.08-4.73 GHz), and the ARBW is equal to 71.6% (2.07-4.38 GHz). The measured average gain has a good value of 3.34 dBi over the CP bandwidth. As a result of these properties, the proposed antenna can be used for various \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref.** & \begin{tabular}{c} **Antenna** \\ **Dimensions** \\ \end{tabular} & \begin{tabular}{c} \(-\)**10 dB BW** \\ **\%** \\ \end{tabular} & \begin{tabular}{c} **3 dB ARBW** \\ **\%** \\ \end{tabular} & \begin{tabular}{c} **Peak Gain** \\ **(dB)** \\ \end{tabular} & \begin{tabular}{c} **Substrate** \\ **Type** \\ \end{tabular} & **Application** & \
\begin{tabular}{c} **CP** \\ **Type** \\ \end{tabular} &
\begin{tabular}{c} **Efficiency** \\ **\%** \\ \end{tabular} \\ \hline
[31] & 0.66\(\lambda\)\(\times\) 0.66\(\lambda\)\(\times\) 0.010\(\lambda\) & 110.0 & 75.7 & 4.52 & RO430B & Fi/WLAN & RHCP & ---- \\
[33] & 0.73\(\lambda\)\(\times\) 0.69\(\lambda\)\(\times\) 0.011\(\lambda\) & 47.27 & 35.79 & 5 & ---- & WiMAX & LHCP & ---- \\  & & & & Digital & & & & \\
[34] & 0.277\(\lambda\)\(\times\) 0.264\(\lambda\)\(\times\) 0.010\(\lambda\) & 20.73 & 6.84 & 3 & FR4 & cellular & RHCP & 95 \\  & & & & systems & & LTE 5G & & \\
[35] & 0.41\(\lambda\)\(\times\) 0.36\(\lambda\)\(\times\) 0.019\(\lambda\) & 16.2 & 12.2 & 3.1 & FR4 &
\begin{tabular}{c} (band 42/43) \\ \end{tabular} & LHCP & ---- \\
[36] & 0.34\(\lambda\)\(\times\) 0.49\(\lambda\)\(\times\) 0.013\(\lambda\) & 10.48 & 10.48 & 3.8 & FR4 & WLAN & LHCP & ---- \\
[51] & 0.40\(\lambda\)\(\times\) 0.40\(\lambda\)\(\times\) 0.02\(\lambda\) & 60.1 & 54.54 & 6 & Rogers 5880 & WLAN/C- & LHCP & 87 \\
[54] & 0.93\(\lambda\)\(\times\) 0.93\(\lambda\)\(\times\) 0.01\(\lambda\) & 68.1 & 57.8 & 5.4 & FR4 & ISM band & LHCP & ---- \\
[55] & 0.75\(\lambda\)\(\times\) 0.75 \(\times\) 0.01\(\lambda\) & 33.3 & 40 & 4 & Rogers 5880 & 5G NR & RHCP & ---- \\  & & & & & & & (n77/n78) & \\
[56] & 0.37\(\lambda\)\(\times\) 0.37\(\lambda\)\(\times\) 0.024\(\lambda\) & 125 & 61 & 4.3 & FR4 &
\begin{tabular}{c} Sub-6 GHz \\ 5G \\ \end{tabular} & LHCP & 90 \\
[57] & 0.87\(\lambda\)\(\times\) 0.87\(\lambda\)\(\times\) 0.02\(\lambda\) & 69.2 & 59 & 4.3 & FR4 & Sub-6 GHz & RHCP & 75 \\ This work & 0.39\(\lambda\)\(\times\) 0.36\(\lambda\)\(\times\) 0.011\(\lambda\) & 78 & 71.6 & 4.68 & FR4 &
\begin{tabular}{c} Sub-6 GHz \\ 5G \\ \end{tabular} & RHCP & 93 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison between the proposed antenna and other slot antennas. wireless CP communication applications. To build upon the proposed design, further optimization of the antenna geometry could be investigated to extend the axial ratio bandwidth ARBW and improve the gain stability across wider frequency ranges. Additionally, the use of reconfigurable or tunable elements can enable dynamic control over the polarization states. Moreover, the array configurations of this antenna could be studied for future 5G and 6G MIMO systems. Conceptualization, A.H.M. and F.M.A. ; methodology, A.H.M. ; investigation, A.H.M., F.M.A., Y.L.A.A.-Y. and S.C.E. ; resources, A.H.M. and F.M.A. ; writing--original draft preparation, A.H.M., F.M.A. and Y.I.A.A.-Y. ; writing--review and editing, F.M.A., Y.I.A.A.-Y. and S.C.E. ; visualization, A.H.M., F.M.A. and Y.I.A.A.-Y. All authors have read and agreed to the published version of the manuscript.