# Dual-Band Shared-Aperture Antenna with Pattern and Polarization Diversity
## 5 Conclusions  
In this paper, a hollow cone monopole low-frequency antenna is designed, then a metal high-frequency Vivaldi antenna is added at the bottom of the cone, which can be fabricated through the 3D printing technique. In the end, a dielectric polarization converter is added above the cone without affecting the radiation performance of the monopole antenna, which realizes the transformation from linear polarization to circular polarization of the Vivaldi antenna. At the same time, the dielectric polarization converter can also improve the broadside gain of the Vivaldi antenna. The working bandwidth of the proposed antenna  
\begin{table}
\begin{tabular}{l l l l l l l} \hline
**Ref.** & **IMBW** & **Radiation Pattern** & **Peak Gain/Bi** & **Isolation /dB** & **Polarization** & **Size \(\lambda_{0}\)\({}^{3}\)** \\ \hline
[1] & 1.61–2.44 GHz & directional/ & & & & & \\  & (40.9\%) & directional & & & & & \\  & 20–36.4 GHz (58.2\%) & & & & & & \\  & 230–32.0 GHz & directional/ & & & & & \\
[3] & (32.73\%) & directional/ & & & & & \\  & 23.64–25.06 GHz & directional & & & & & \\  & 2.37–2.55 GHz & & & & & \\
[4] & (7.3\%) & & & & & \\  & 23.99–24.46 GHz & directional/ & & & & & \\  & (2.23\%) & & & & & \\  & 3.02–5.03 GHz & & & & & \\
[5] & (49,94\%) & omnidirectional/ & & & & & \\  & 27.3–28.8 GHz & directional/ & & & & \\  & (5.35\%) & & & & & \\  & 3.2–4.05 GHz & & & & & \\
[14] & (23.45\%) & directional/ & & & & & \\  & (4.8\%) & & & & & \\  & 3.2–4.05 GHz & & & & & \\
[16] & (23.45\%) & directional/ & & & & & \\
[26.8–29.55 GHz & directional & & & & & \\  & (9.76\%) & & & & & \\  & 2.12–275 GHz & & & & & \\
[8] & (25.8\%) & directional/ & & & & & \\
[8] & 5.69–5.91 GHz & directional & & & & \\  & (3.8\%) & & & & & \\  & 2.40–2.48 GHz & & & & & \\
[20] & (23.8\%) & directional/ & & & & \\  & 27.7–28.1 GHz & directional & & & & \\  & (1.43\%) & & & & & \\  & 3.41–3.59 GHz & & & & & \\
[21] & (5.14\%) & directional/ & & & & \\
[22] & 26.62–30.26 GHz & directional & & & & \\  & (12.8\%) & & & & & \\ This & 2.09–11.61 GHz & Omnidirectional/ & & & & \\  & (138.9\%) & directional/ & & & & \\  & 21.6–29.6 GHz (31\%) & & & & & \\ \hline \end{tabular}
\end{table}
Table 2: Comparison of different dual-band antennas.  
is 2.09-11.61 GHz (9.52 GHz, 138.9%) and 21.6-29.6 GHz (8 GHz, 31%), which can be a good candidate for multi-band communication systems.  
Conceptualization, C.Z.; methodology, J.C. and T.G.; validation, T.G. and J.C.; formal analysis, J.C. and D.H.; investigation, T.G. and D.H.; data curation, T.G. and D.H.; writing, J.C., T.G. and C.Z.; supervision, C.Z.; project administration, C.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Natural Science Foundation of China under Grant 62371088 and Grant U23A20290, the Fundamental Research Funds for the Central Universities under Grant DUT24 ZD126, and a grant from the National Key Laboratory of Electromagnetic Information Control and Effects under Grant HX20231736.  
Not applicable.  
Data Availability Statement: Data is contained within the article.  
The authors declare no conflicts of interest.