# Hybrid Mode Reconfigurable Antenna with V-Shaped Extrudes for Cognitive Radio Applications
## 4 Conclusions  
This paper defines the proposal of the final designed antenna with every step. In the very first step, a simple rectangular patch antenna with a low size and a bandwidth of 800 MHz, from 7.5 GHz to 8.3 GHz, is analysed, which can be used in industrial applications \begin{table}
\begin{tabular}{c c c c c} \hline
**Diode** & **Frequency Bands** & **Resonance** & **Return** & **Main Lobe Direction** & **Main Lobe Directivity** \\
**Switching** & **(GHz)** & **Frequency (GHz)** & **Loss (dB)** & **(At 5.5 GHz) (Degree)** & **(At 5.5 GHz) (dBi)** \\ \hline ON–ON & 2.7–5.9 & 5.1 & \(-\)24 & 155 & 3.5 \\  & 1.4–1.5 & 1.5 & \(-\)17 & & \\ ON–OFF & 2.7–4.4 & 3.2 & \(-\)16 & 155 & 3.48 \\  & 4.6–5.8 & 5.1 & \(-\)26 & & \\  & 1.4–1.5 & 1.5 & \(-\)18 & & \\ OFF–ON & 2.7–4.2 & 3.2 & \(-\)16 & 155 & 3.49 \\  & 4.6–5.9 & 5.1 & \(-\)36 & & \\  & 2.3–3 & 2.6 & \(-\)17 & & \\ OFF–OFF & 4.1–5.8 & 5.1 & \(-\)30 & 155 & 3.5 \\  & 7.8–8.3 & 8.1 & \(-\)15 & & \\ \hline \end{tabular}
\end{table} 
Table 2: Results for frequency-reconfigurable antenna. Figure 12: Surface current at 3.5 GHz: (**a**) D1(ON) and D2(ON); (**b**) D1(OFF) and D2(ON); (**c**) D1(ON) and D2(OFF); (**d**) D1(OFF) and D2(OFF) & d at 4 GHz; (**e**) D1(ON) and D2(ON); (**f**) D1(OFF) and D2(ON); (**g**) D1(ON) and D2(OFF); (**h**) D1(OFF) and D2(OFF). such as radar systems, materials processing, and testing. In the next step, two V-shaped slots reduced from the patch result in a frequency band from 7.8 GHz to 8.9 GHz and can be used in applications, including radar systems for tracking and detecting objects, such as aircraft, ships, and missiles; and point-to-multipoint and point-to-point communication systems. A DGS is then employed, which provides a bandwidth enhancement from 3.1 GHz to 7.7 GHz and can be used for 4G and 5G cellular communication and Wi-fi networks with high data rates. Finally, the antenna is modified to be reconfigurable by introducing two p-i-n diodes between one parasitic element and one radiating element. The projected antenna is compact in size, as analysed in Table 4, and demonstrates multi-band switching with different radiation patterns in different directions, showing frequency and pattern reconfiguration. After a reviewing a wide range of the literature, it was concluded that the proposed structure is compact in size and can be reconfigured for five bands with pattern variations, which are shown in detail in Table 4. Compared to the substrate size of 80 \(\times\) 30 mm\({}^{2}\)[24], the proposed design is compact as it occupies 32 \(\times\) 36 mm\({}^{2}\), which is approximately reduced to 52% with pattern and frequency reconfiguration. Frequency reconfiguration is demonstrated at 1.5/2.6/3.2/5.1/8.1 GHz by switching the diode for its four conditions. At 3.5 GHz, the proposed antenna exhibits radiation pattern switching with variations of 7\({}^{\circ}\), 158\({}^{\circ}\), 173\({}^{\circ}\), and 175\({}^{\circ}\); at 4 GHz, it exhibits variations of 11\({}^{\circ}\), 15\({}^{\circ}\), 165\({}^{\circ}\), and 344\({}^{\circ}\), which defines the hybrid reconfiguration. The structured antenna is novel, with a wide spectrum of hybrid reconfiguration in terms of pattern and frequency and can be used for the latest wireless technology to provide high data rate. **Author Contributions:** Conceptualization, A.S. and A.R. ; methodology, A.S., A.R., H.M.R.A.-K., M.G.S. and A.K.S.Y. ; software, A.S. and A.R. ; validation, A.S., A.R. and H.M.R.A.-K.; formal analysis, A.S., A.R., H.M.R.A.-K., M.G.S. and A.K.S.Y. ; investigation, A.S. and A.R; resources, A.S., A.R. and H.M.R.A.-K.; writing--original draft preparation, A.S., A.R. and H.M.R.A.-K.; writing--review and editing, A.S., A.R. and H.M.R.A.-K.; visualization, A.S. and A.R. ; supervision, A.R. ; project administration, A.S. and A.R. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received no external funding. **Informed Consent Statement:** Not applicable.