# Hybrid Mode Reconfigurable Antenna with V-Shaped Extrudes for Cognitive Radio Applications
## 2 Antenna Design
With D-1 OFF and D-2 OFF, the main lobe is yet again at 155\({}^{\circ}\) with the same radiation pattern shape, demonstrating the stable radiation pattern of the frequency-reconfigurable antenna at 5.5 GHz, as shown in Figure 9d. Compound/hybrid reconfiguration refers to the capability of an antenna to collectively tune different parameters. Key examples of these parameters are frequency and radiation patterns. Multiple reconfigurations, which combine beam scanning with frequency agility, have greater efficiency in each spectrum. Here, the designed antenna shows a return loss plot of less than \(-10\) dB for each condition of switching the p-i-n diode; it provides a radiation pattern for 3.5 GHz, and 4 GHz for pattern reconfigurability for observation. The latest 5G technology includes the frequency range from 2.4 GHz to 4.2 GHz in the mid-band, which covers 3.5 GHz and 4 GHz. Mid-band frequencies strike a balance between coverage and capacity. They can travel shorter distances than low-band frequencies but can carry more data at faster speeds. Mid-band frequencies are used for 5G in urban and suburban areas, where there is a higher density of users and more demand for high-speed data. A frequency of 3.5 GHz is one of the key frequency bands used for 5G wireless communication networks, which offer faster data rates and lower latency than previous generations of wireless networks. Figure 2:0 Simulated and measured return loss of frequency-reconfigurable rectangular patch antenna with two V-shaped extrudes using DGS: (**a**) D1(ON) and D2(ON); (**b**) D1(OFF) and D2(ON); (**c**) D1(ON) and D2(OFF); (**d**) D1(OFF) and D2(OFF). Figure 10 shows the radiation pattern at 3.5 GHz. The main lobe appears at different directions, depending on the switch condition of diodes. Beam switching is accomplished by changing the phase of the signal fed to the antenna. When the signal is fed to the patch, it creates an electromagnetic field that radiates from the patch. The shape and direction of this radiated field determine the radiation pattern of the antenna. By controlling the phase of the signal fed to the patch, the direction of the radiated field can be changed; in turn, this changes the direction of the radiation pattern. Beam switching is a useful technique in antenna design as it allows the antenna to be used for directional communication with multiple targets without having to physically move the antenna. Here, switching in phase is achieved using p-i-n diodes, which are connected between the patch and rectangular element. With both diodes in ON mode, as shown in Figure 10a, the main lobe appears at \(175^{\circ}\) with 3 dB angular width of \(94^{\circ}\). When D1 is OFF and D2 is ON, it shows the main lobe in \(173^{\circ}\), as explained in Figure 10b. When D1 is switched to ON and D2 is switched to OFF, the main lobe is shown at \(7^{\circ}\), as shown in Figure 10c, with an angular width of \(100^{\circ}\), while with both diodes in the OFF condition, the main lobe is shown at \(158^{\circ}\) with an angular width of \(85^{\circ}\), as depicted in Figure 10d. At 3.5 GHz, the antenna shows the antenna pattern variation in different directions: \(7^{\circ},158^{\circ},175^{\circ}\), and \(173^{\circ}\). Figure 2:1 Simulated radiation pattern plot at 5.5 GHz of frequency-reconfigurable rectangular patch antenna with two V-shaped extrudes with DGS: (**a**) D1(ON) and D2(ON); (**b**) D1(OFF) and D2(ON); (**c**) D1(ON) and D2(OFF); (**d**) D1(OFF) and D2(OFF). Figure 11 shows the radiation pattern at 4 GHz for pattern reconfiguration. It shows the radiation pattern in eight shapes, with a beamwidth from 60\({}^{\circ}\) to 310\({}^{\circ}\) under D1-ON and D2-ON conditions, as depicted in Figure 11a. The main lobe appears at 11\({}^{\circ}\) with 3 dB and an angular width of 94\({}^{\circ}\). Switching Diode D1-OFF and D2-ON, the main lobe appears at 165\({}^{\circ}\), as shown in Figure 11b. Under conditions of Diode D1-ON and D2-OFF, it shows the main lobe at 15\({}^{\circ}\), as presented in Figure 11c.