# Antennas for Licensed Shared Access in 5G Communications with LTE Mid- and High-Band Coverage
## 6 Conclusions  
First, a planar antenna was designed for application in mobile devices. The operating bandwidth of the planar antenna is 1170 MHz (1.38-2.55 GHz), which covers  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ref.** & **Efficiency \({}^{*}\) (\%)** & **Bandwidth (GHz)** & **Antenna Height** & **Area** & **Substrate (Thickness)** \\ \hline
[16] & 64–83 (M) & 1.68–2.74 & 5 & 3360 & FR4 (0.8 mm) \\ \hline
[17] & 50–73 (M) & 1.63–2.74 & 5.8 & 2240 & FR4 (0.8 mm) \\ \hline
[18] & 65–83 (M) & 1.71–2.69 & 7 & 567 & FR4 (0.4 mm) \\ \hline
[22] & 50–93 (M), 53–73 (H) & 1.69–4.02 & 7 & 800 & FR4 (0.8 mm) \\ \hline
[23] & 48–84 (M), 62–91 (H) & 1.71–2.69, 3.4–3.8 & 6 & 2400 & FR4 (0.8 mm) \\ \hline
[24] & 60–75 (M), 78–91 (H) & 1.71–3.85 & 5 & 560 & FR4 (0.8 mm) \\ \hline
[25] & 59–90 (M), 50–85 (H) & 1.71–3.02, 3.37–3.9 & 5 & 1125 & FR4 (1.6 mm) \\ \hline
[27] & \textgreater{}50 (M and H) & 1.7–2.9, 3.4–3.8 & 5 & 2812 & FR4 (0.8 mm) \\ \hline
[31] & 58–77 (M) & 1.66–2.77 & 3 & 550 & FR4 (1 mm) \\ \hline
[32] & 57–87 (M) & 1.6–2.7 & 4 & 525 & FR4 (1 mm) \\ \hline
[33] & Not given & 1.48–2.176, 2.28–2.775, & 0.8 & 1020 & FR4 (0.8 mm) \\  & & 2.97–4.98, 5.125–6 & & & \\ \hline
[34] & 40–66 (M) & 1.71–2.85 & 0.8 & 874 & FR4 (0.8 mm) \\ \hline
[35] & 88–95 (M) (rad) & 1.67–2.87 & 6 & 560 & FR4 (0.8 mm) \\ \hline Ant#3 & 66–96 (M), 79–94 (H) & 1.37–4 & 4 & 510 & FR4 (0.8 mm) \\ \hline \hline \end{tabular}  
* M and H stand for the mid and high bands, respectively. Area = length \(\times\) width (mm\({}^{2}\)). The antenna height is in millimeters.  
\end{table}
Table 4: Performance comparison of the reference antennas and the proposed wideband antenna for the LTE mid and high bands.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameters** & **LSA Antenna** & **Dual-Band Antenna** & **Wideband Antenna** \\  & **(Ant#1)** & **(Ant#2)** & **(Ant#3)** \\ \hline Physical Area (mm\({}^{2}\)) & 600 & 585 & 510 \\ \hline Bandwidth (GHz) & 1.38–2.55 & 1.39–2.84, 3.27–3.97 & 1.37–4 \\ \hline Efficiency (\%) & 66–89 & 62–90 (M), 66–88 (H) \({}^{*}\) & 66–96 (M), 79–94 (H) \\ \hline Gain (dBi) & 1.3–3.6 & 1.4–3.4 (M), 4.2–6.1 (H) & 1.6–2.9 (M), 4.2–5.6 (H) \\ \hline Nulls in Rad. Pat. & In x–y plane & In x–y plane (H) & - \\ \hline \multicolumn{3}{l}{\({}^{*}\)M and H stand for the LTE mid and high bands, respectively.} \\ \end{tabular}
\end{table}
Table 3: Performance comparison of the presented LSA (Ant#1), dual-band (Ant#2), and wideband (Ant#3) antennas.  
both LSA frequency bands. Then, two novel antennas were designed to cover both LSA bands (1452-1492 and 2300-2400 MHz) and the mid- (1427-2690 MHz) and high-LTE (3300-3800 MHz) bands. Although these antennas have a small vertical plate at the edge of the radiating element, the areas occupied by the dual-band and wideband antennas are 3% and 15% smaller than most of the reference planar antennas. There are nulls in the radiation patterns of the planar antenna and the dual-band antenna. The radiation patterns of the wideband antenna do not have any nulls. Finally, in order to prove the concept, the wideband antenna was fabricated and measured. The measured \(-6\) dB impedance bandwidth of the prototype is 1.37-4 GHz, which covers all the targeted frequency bands.  
Conceptualization: K.M.M.; methodology: K.M.M., D.K.K. and K.P.E.; investigation: all authors; experimental measurements: K.M.M.; writing--original draft preparation: K.M.M.; writing--review and editing: [PERSON], [PERSON] and K.P.E.; supervision: [PERSON] and [PERSON]. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the International Postgraduate Research Scholarship (IPRS) and Macquarie University Research Excellence Scholarship (MQRES).  
Not applicable.  
The authors declare no conflict of interest.