# Ultrathin Microwave Devices for Polarization-Dependent Wavefront Shaping Based on an Anisotropic Metasurface

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## Abstract

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## Featured Application

**The proposed approach may pave a way towards the practical applications of metasurfaces in the microwave band.**

## Abstract

## 1. Introduction

## 2. Design Principle and Simulation Method

_{11}of the proposed metasurface at a frequency of 15 GHz as a function of dx and dy. Figure 2a,b shows the amplitude and phase of S

_{11}under x-polarized incidence, with dx and dy varying from 4 mm to 6.5 mm, respectively. The results indicate a large amplitude over 0.98, and a phase shift of about 320° with varying dx, while S

_{11}is independent on dy. Figure 2c,d shows the amplitude and phase of S

_{11}under y-polarized incidence, with dx and dy varying from 4 mm to 6.5 mm, respectively. It is shown that the dependence of S

_{11}under y-polarized incidence on dx and dy is similar to that of under x-polarized on dy and dx, respectively, due to the symmetry of the proposed metasurface. Overall, the local phase for x- and y-polarized microwaves can be independently tailored by controlling the geometrical parameters, which is called the double-phase modulating mechanism.

_{11}for the unit cell with and without the square ring are compared in Figure 3. Here, dy is fixed 4.5 mm and dx is varying from 4 mm to 6.5 mm. Figure 3a,c shows that the reflective amplitude is always over 0.98 with and without the square ring, respectively, indicating the proposed structure is high efficiently. Figure 3b shows that the phase shift of S

_{11}for the proposed structure under x-polarized incidence covers a broad angle range of 320° (from −45° to −365°). In contrast, Figure 3d shows that the phase shift of S

_{11}for the structure without the square ring merely covers an angle range of 300° (from −63.9° to −365°) under x-polarized incidence. For the cases under y-polarized incidence (red lines), both the amplitude and phase are independent on dx. In addition, it is easy to understand that the dependence of phase shift on dy is opposite, due to the structural symmetry. Therefore, these results clearly demonstrate that the metal square ring can effectively extend the ability of the proposed structure to manipulate the reflective phase.

## 3. Results and Discussion

## 4. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**Schematic of the unit cell. (

**a**) Perspective view from the front (top panel) and back (bottom panel), (

**b**) detailed front view of the unit cell with geometrical parameters.

**Figure 2.**Simulated reflective coefficient S

_{11}of the unit cell. The (

**a**) amplitude and (

**b**) phase of S

_{11}under x-polarized incidence as functions of dx and dy. The (

**c**) amplitude and (

**d**) phase of S

_{11}under y-polarized incidence as functions of dx and dy.

**Figure 3.**(

**a**) The amplitude and (

**b**) phase of S

_{11}of the proposed unit cell as a function of dx. (

**c**) The amplitude and (

**d**) phase of S

_{11}of a unit cell without square ring as a function of dx. Here, dy = 4.5 mm.

**Figure 4.**The schematic of the designed metasurface. (

**a**) A supercell consists of six cells, (

**b**) the designed metasurface constituted of 3 × 2 supercells.

**Figure 5.**The near-field distribution of electric field for (

**a**) x- and (

**b**) y-polarized waves. (

**c**) Return loss of the x- and y-polarized waves.

**Figure 6.**(

**a**) The designed metasurface. The phase distributions for (

**b**) the x- and (

**c**) y-polarized components.

**Figure 7.**Electric distribution in the x–y plane at z = 40 mm for (

**a**) x- (

**b**) y-polarized incident waves. Electric distribution in the x–z and y–z planes for (

**c**) x- (

**d**) y-polarized incident waves, respectively. Intensity profile at a focus spot along the (

**e**) x- (

**f**) y-axis for incident x- and y-polarized waves.

n | 1 | 2 | 3 | 4 | 5 | 6 |
---|---|---|---|---|---|---|

dx (mm) | 4.00 | 4.71 | 4.88 | 5.00 | 5.16 | 5.73 |

dy (mm) | 5.73 | 5.16 | 5.00 | 4.88 | 4.71 | 4.00 |

Φ_{x} (deg) | −45.6 | −105.6 | −165.6 | −225.6 | −285.6 | −345.6 |

Φ_{y} (deg) | −345.6 | −285.6 | −225.6 | −165.6 | −105.6 | −45.6 |

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**MDPI and ACS Style**

Guo, K.; Guo, Z. Ultrathin Microwave Devices for Polarization-Dependent Wavefront Shaping Based on an Anisotropic Metasurface. *Appl. Sci.* **2018**, *8*, 2471.
https://doi.org/10.3390/app8122471

**AMA Style**

Guo K, Guo Z. Ultrathin Microwave Devices for Polarization-Dependent Wavefront Shaping Based on an Anisotropic Metasurface. *Applied Sciences*. 2018; 8(12):2471.
https://doi.org/10.3390/app8122471

**Chicago/Turabian Style**

Guo, Kai, and Zhongyi Guo. 2018. "Ultrathin Microwave Devices for Polarization-Dependent Wavefront Shaping Based on an Anisotropic Metasurface" *Applied Sciences* 8, no. 12: 2471.
https://doi.org/10.3390/app8122471