**4.3 Fabrication and measurement of the antenna**

The photograph of the fabricated antenna is shown in **Figure 14**. After simulation, we find that the antenna can work in at kinds of states. We measured the S11 and radiation patterns of the antenna in these 11 states. **Table 3** gives the detail performance of the antenna in different states, including the states of the diodes, beam directions, and maximum gain. Because the antenna structure at state 2 (4, 6, 8, 10) is completely symmetrical to that at state 3 (5, 7, 9, 11), so they have same the S11. For simplicity, we just show the simulated and measured S11 in states of 1, 2, 4, 6, 8, and 10 in **Figure 15**. The measured results agree well with the simulated ones. The measured impedance bandwidth of the antenna is 4.92–5.08 GHz (3.2%). The S11 of the antenna only has little difference between different states.

The radiation patterns of the antenna are measured in anechoic chamber. The simulated and measured radiation patterns of the antenna are presented in **Figure 16**. Good agreement is obtained between the measured results and the simulated ones. We know that the main beam of the antenna tilts in *xoz* plane,

so the radiation patterns of the antennas are all in *xoz* plane. The main beam of the antenna in state 1 is toward the +*z* direction. However, it tilts to –*y* direction in states 2, 4, 6, 8, and 10 and to +*y* direction in states 3, 5, 7, 9, and 11. And the same

*Radiation patterns of the antenna: (a) states 1, 2, and 4; (b) states 6, 8, and 10; (c) states 1, 3, and 5;*

*Reconfigurable Fabry-Pérot Cavity Antenna Basing on Phase Controllable Metasurfaces*

*DOI: http://dx.doi.org/10.5772/intechopen.91695*

The simulated maximum gain of the antenna at state 1 is 11.8 dB, and the measured maximum gain is 11.1 dB. With the increase of the beam tilted angle, the maximum gain of the antenna decreases. The antenna obtains maximum beam tilted angle (about 54°) at states 10 and 11,and the maximum gain of the antenna decreases to 6.3 dB. The antenna remains to have high-gain performance while realizing beam tilting. Besides, the gain floating of the antenna at all states in the operating band are less than 2.8%. So the impedance bandwidth of the antenna is

In the last section, we design an FPC antenna with large beam steering angle. However, it can only realize beam tilting in one plane. In practice application, we prefer the antenna to be able to steer the beam in two directions. So in this Section, we will design a configurable PRS to realize two-dimensional beam steering of the

The unit cell of the PRS is shown in **Figure 17**. It is also printed on the substrate of

FR4. Each unit cell consists of four square patches. Four PIN diodes are inserted between two adjacent patches. The four diodes are controlled simultaneously, and the

tilted angle is obtained at states 2 (4, 6, 8, 10) and 3 (5, 7, 9, 11).

**5. Polarization and pattern reconfigurable FPC antenna**

the working band of the antenna.

**5.1 Design of the reconfigurable PRS**

FPC antenna [17].

**235**

**Figure 16.**

*and (d) states 7, 9, and 11.*

**Figure 15.** *Simulated and measured S11: (a) states 1, 2, and 4 and (b) states 6, 8, and 10.*

*Reconfigurable Fabry-Pérot Cavity Antenna Basing on Phase Controllable Metasurfaces DOI: http://dx.doi.org/10.5772/intechopen.91695*

**Figure 16.** *Radiation patterns of the antenna: (a) states 1, 2, and 4; (b) states 6, 8, and 10; (c) states 1, 3, and 5; and (d) states 7, 9, and 11.*

so the radiation patterns of the antennas are all in *xoz* plane. The main beam of the antenna in state 1 is toward the +*z* direction. However, it tilts to –*y* direction in states 2, 4, 6, 8, and 10 and to +*y* direction in states 3, 5, 7, 9, and 11. And the same tilted angle is obtained at states 2 (4, 6, 8, 10) and 3 (5, 7, 9, 11).

The simulated maximum gain of the antenna at state 1 is 11.8 dB, and the measured maximum gain is 11.1 dB. With the increase of the beam tilted angle, the maximum gain of the antenna decreases. The antenna obtains maximum beam tilted angle (about 54°) at states 10 and 11,and the maximum gain of the antenna decreases to 6.3 dB. The antenna remains to have high-gain performance while realizing beam tilting. Besides, the gain floating of the antenna at all states in the operating band are less than 2.8%. So the impedance bandwidth of the antenna is the working band of the antenna.
