# Quad-Band Circular Polarized Antenna for GNSS, 5G and WIFI-6E Applications
## 6 Conclusions  
A circularly polarized antenna with simple structure, multiple frequency bands, and a wide axial ratio bandwidth has been presented. The proposed antenna adds an L-shaped  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**References** & **Size (mm3)** & **Number of Bands** & **S11 \textless{} 10 dB** & **AR \textless{} 3 dB** & **Applications** \\ \hline
[8] & \(150\times 150\times 18\) & 2 & 12.7\%, 10.1\% & 3.3\%,3.1\% & GPS \\ \hline
[9] & \(101\times 64\times 1.52\) & 1 & 86.9\% & 74.3\% & 5G, WIFI-6E \\ \hline
[15] & \(50\times 50\times 5\) & 1 & 3.2\% & 1.8\% & GPS, GLONASS \\ \hline
[19] & \(47.7\times 47.7\times 5.8\) & 1 & 19.7\% & 13.9\% &
\begin{tabular}{c} Telemetry tracking \\ and command system \\ \end{tabular} \\ \hline
[22] & \(93.6\times 96\times 1\) & 2 & 14.75\%,9.44\% &
\begin{tabular}{c} around \\ 2.84 GHz,5.24 GHz \\ \end{tabular} & WLAN \\ \hline
[23] & \(130\times 130\times 31.52\) & 2 & 40.57\% & 6.56\%,7.74\% & GPS \\ \hline
[24] & \(120\times 120\times 29.6\) & 4 & \begin{tabular}{c} 21.1\%, 12.8\%, 27.1\%, \\ 7.5\% \\ \end{tabular} & \
\begin{tabular}{c} 11.6\%, 7.6\%, 7.0\%, \\ 7.1\% \\ \end{tabular} &
\begin{tabular}{c} GPS, BPS, WLAN, \\ Wi-MAX \\ \end{tabular} \\ \hline
[25] & \(35\times 35\times 13.8\) & 3 & 13.0\%, 18.2\%, 14.7\% & 3.53\%, 1.73\%, 13.62\% & Satellite application \\ \hline
[26] & \(25\times 25\times 1\) & 3 & 23.4\%,56.5\%, 31.14\% & 10.1\%, 4.95\%, 10.44\% &
\begin{tabular}{c} WLAN/C band \\ X/Ku band \\ \end{tabular} \\ \hline
[31] & \(60\times 60\times 1.0\) & 3 & 44.0\%, 70.9\% & 35.9\%, 44\%, 6.3\% & WLAN, 5G \\ \hline This work & \(80\times 80\times 1.6\) & 4 & \
\begin{tabular}{c} 75.8\%, 55.8\%, 39.9\%, \\ 10.3\% \\ \end{tabular} &
\begin{tabular}{c} 59.4\%, 35.8\%, 8.4\%, \\ 2.6\% \\ \end{tabular} & GNSS, 5G, WIFI-6E \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of the GNSS CP antennas.  
Figure 12: The simulated and measured gain.  
-stub and a rectangular patch, on the basis of the L-shaped radiator and rectangular frame, which changes the current distribution by cutting grooves to achieve the superior performance of multiple frequency bands and the wide axial ratio bandwidth. The measured \(-10\) dB bandwidth is 75.8% (0.95-2.11 GHz), 55.8% (3.05-5.39 GHz), 39.9% (5.84-8.19 GHz), and 10.3% (9.14-10.68 GHz), and 3-dB ARBWs are 59.4% (1.16-2.14 GHz), 35.8% (3.23-4.64 GHz), 8.4% (5.70-6.20 GHz), and 2.6% (7.51-7.71 GHz). Results show that the antenna can operate in the frequency bands from 1.16 to 2.14 GHz in RHCP for GNSS, from 3.23 to 4.64 GHz in LHCP for 5G, and from 5.925 to 7.125 GHz for WIFI-6E.  
Conceptualization, X.L.; methodology, H.W.; software, X.Y.; validation, J.W.; data curation, H.W.; writing--original draft preparation, H.W.; writing--review and editing, X.L.; funding acquisition, X.L., X.Y. and J.W. All authors have read and agreed to the published version of the manuscript. This work is funded in part by the University Synergy Innovation Program of Anhui Province (GXXT-2021-027), the National Natural Science Foundation of China under the contract number of 61871003 and the open project of the state key laboratory of complex electromagnetic environment effects on electronics and information system under grant numbers of CEMEE2022Z0201B, CEMEE2021K0202A. The authors declare no conflict of interest.