# A 4 × 4 Active Antenna Array with Adjustable Beam Steering

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Complete Structure

#### 2.1. Power Divider

#### 2.2. Phase Shifter

#### 2.3. Antenna

## 3. Phase Shift Characterization

#### 3.1. Error Analysis

## 4. Far-Field Measurements

#### 4.1. Beamforming Strategy

#### 4.2. Measurement Setup

#### 4.3. Measurement Results

#### 4.4. Comparison with Simulation

## 5. Discussion

#### 5.1. Power Budget

#### 5.2. Comparison with Other Works

## 6. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

- Balanis, C. Antenna Theory: Analysis and Design, 4th ed.; Wiley: Hoboken, NJ, USA, 2016; pp. 285–293. [Google Scholar]
- Meng, X.; Nekovee, M.; Wu, D. The Design and Analysis of Electronically Reconfigurable Liquid Crystal-Based Reflectarray Metasurface for 6G Beamforming, Beamsteering, and Beamsplitting. IEEE Access
**2021**, 9, 155564–155575. [Google Scholar] [CrossRef] - Li, W.; Wang, Y.M.; Hei, Y.; Li, B.; Shi, X. A Compact Low-Profile Reconfigurable Metasurface Antenna with Polarization and Pattern Diversities. IEEE Antennas Wirel. Propag. Lett.
**2021**, 20, 1170–1174. [Google Scholar] [CrossRef] - Zhu, H.L.; Liu, X.H.; Cheung, S.W.; Yuk, T.I. Frequency-Reconfigurable Antenna Using Metasurface. IEEE Trans. Antennas Propag.
**2014**, 62, 80–85. [Google Scholar] [CrossRef] - Wang, M.; Liao, D.; Dai, J.Y.; Chan, C.H. Dual-Polarized Reconfigurable Metasurface for Multifunctional Control of Electromagnetic Waves. IEEE Trans. Antennas Propag.
**2022**, 70, 4539–4548. [Google Scholar] [CrossRef] - Rao, J.; Zhang, Y.; Tang, S.; Li, Z.; Shen, S.; Chiu, C.Y.; Murch, R. A Novel Reconfigurable Intelligent Surface for Wide-Angle Passive Beamforming. IEEE Trans. Microw. Theory Tech.
**2022**, 70, 5427–5439. [Google Scholar] [CrossRef] - Ibrahim, E.; Nilsson, R.; Van De Beek, J. Binary Polarization Shift Keying with Reconfigurable Intelligent Surfaces. IEEE Wirel. Commun. Lett.
**2022**, 11, 908–912. [Google Scholar] [CrossRef] - Lin, H.; Yu, W.; Tang, R.; Jin, J.; Wang, Y.; Xiong, J.; Wu, Y.; Zhao, J. A dual-band reconfigurable intelligent metasurface with beam steering. J. Phys. Appl. Phys.
**2022**, 55, 245002. [Google Scholar] [CrossRef] - Zou, X.; Yao, J.; Chung, K.L.; Lai, G.; Zeng, W.; Gu, W. A Comparative Study Between Reconfigurable Intelligent Surface and Reflectarray Antenna. In Proceedings of the 2022 IEEE 5th International Conference on Electronic Information and Communication Technology (ICEICT), Hefei, China, 21–23 August 2022; pp. 846–848. [Google Scholar] [CrossRef]
- Björnson, E.; Wymeersch, H.; Matthiesen, B.; Popovski, P.; Sanguinetti, L.; de Carvalho, E. Reconfigurable Intelligent Surfaces: A signal processing perspective with wireless applications. IEEE Signal Process. Mag.
**2022**, 39, 135–158. [Google Scholar] [CrossRef] - Cheng, Q.; Zhang, L.; Dai, J.Y.; Tang, W.; Ke, J.C.; Liu, S.; Liang, J.C.; Jin, S.; Cui, T.J. Reconfigurable Intelligent Surfaces: Simplified-Architecture Transmitters—From Theory to Implementations. Proc. IEEE
**2022**, 110, 1266–1289. [Google Scholar] [CrossRef] - Abb, M.; Wang, Y.; de Groot, C.H.; Muskens, O.L. Hotspot-mediated ultrafast nonlinear control of multifrequency plasmonic nanoantennas. Nat. Commun.
**2014**, 5, 4869. [Google Scholar] [CrossRef] - Reis, J.R.; Vala, M.; Caldeirinha, R.F.S. Review Paper on Transmitarray Antennas. IEEE Access
**2019**, 7, 94171–94188. [Google Scholar] [CrossRef] - Huang, C.; Pan, W.; Ma, X.; Zhao, B.; Cui, J.; Luo, X. Using Reconfigurable Transmitarray to Achieve Beam-Steering and Polarization Manipulation Applications. IEEE Trans. Antennas Propag.
**2015**, 63, 4801–4810. [Google Scholar] [CrossRef] - Lau, J.Y.; Hum, S.V. A Wideband Reconfigurable Transmitarray Element. IEEE Trans. Antennas Propag.
**2012**, 60, 1303–1311. [Google Scholar] [CrossRef] - Nicholls, J.G.; Hum, S.V. Full-Space Electronic Beam-Steering Transmitarray with Integrated Leaky-Wave Feed. IEEE Trans. Antennas Propag.
**2016**, 64, 3410–3422. [Google Scholar] [CrossRef] - Reis, J.R.; Caldeirinha, R.F.S.; Hammoudeh, A.; Copner, N. Electronically Reconfigurable FSS-Inspired Transmitarray for 2-D Beamsteering. IEEE Trans. Antennas Propag.
**2017**, 65, 4880–4885. [Google Scholar] [CrossRef] - Di Palma, L.; Clemente, A.; Dussopt, L.; Sauleau, R.; Potier, P.; Pouliguen, P. Circularly-Polarized Reconfigurable Transmitarray in Ka-Band with Beam Scanning and Polarization Switching Capabilities. IEEE Trans. Antennas Propag.
**2017**, 65, 529–540. [Google Scholar] [CrossRef] - Luo, C.W.; Zhao, G.; Jiao, Y.C.; Chen, G.T.; Yan, Y.D. Wideband 1 bit Reconfigurable Transmitarray Antenna Based on Polarization Rotation Element. IEEE Antennas Wirel. Propag. Lett.
**2021**, 20, 798–802. [Google Scholar] [CrossRef] - Wan, X.; Xiao, Q.; Zhang, Y.Z.; Li, Y.; Eisenbeis, J.; Wang, J.W.; Huang, Z.A.; Liu, H.X.; Zwick, T.; Cui, T.J. Reconfigurable Sum and Difference Beams Based on a Binary Programmable Metasurface. IEEE Antennas Wirel. Propag. Lett.
**2021**, 20, 381–385. [Google Scholar] [CrossRef] - Wang, Y.; Xu, S.; Yang, F.; Li, M. A Novel 1 Bit Wide-Angle Beam Scanning Reconfigurable Transmitarray Antenna Using an Equivalent Magnetic Dipole Element. IEEE Trans. Antennas Propag.
**2020**, 68, 5691–5695. [Google Scholar] [CrossRef] - Wang, Z.X.; Yang, H.; Shao, R.; Wu, J.W.; Liu, G.; Zhai, F.; Cheng, Q.; Cui, T.J. A Planar 4-Bit Reconfigurable Antenna Array Based on the Design Philosophy of Information Metasurfaces. Engineering
**2022**, 17, 64–74. [Google Scholar] [CrossRef] - Huang, C.; Pan, W.; Luo, X. Low-Loss Circularly Polarized Transmitarray for Beam Steering Application. IEEE Trans. Antennas Propag.
**2016**, 64, 4471–4476. [Google Scholar] [CrossRef] - Li, X.; Yang, H.; Shao, R.; Zhai, F.; Liu, G.; Wang, Z.X.; Gao, H.F.; Fan, G.; Wu, J.W.; Cheng, Q.; et al. Low-Cost and High-Performance 5-Bit Programmable Phased Array at Ku-Band. Prog. Electromagn. Res.
**2022**, 175, 29–43. [Google Scholar] [CrossRef] - Tang, J.; Xu, S.; Yang, F.; Li, M. Design and Measurement of a Reconfigurable Transmitarray Antenna with Compact Varactor-Based Phase Shifters. IEEE Antennas Wirel. Propag. Lett.
**2021**, 20, 1998–2002. [Google Scholar] [CrossRef] - Yang, H.; Yang, F.; Xu, S.; Li, M.; Cao, X.; Gao, J.; Zheng, Y. A Study of Phase Quantization Effects for Reconfigurable Reflectarray Antennas. IEEE Antennas Wirel. Propag. Lett.
**2017**, 16, 302–305. [Google Scholar] [CrossRef] - Vilenskiy, A.; Makurin, M.; Poshisholina, E.; Lee, C. Design Technique for Varactor Analog Phase Shifters with Equalized Losses. Prog. Electromagn. Res. C
**2018**, 86, 1–16. [Google Scholar] [CrossRef] - Burdin, F.; Iskandar, Z.; Podevin, F.; Ferrari, P. Design of Compact Reflection-Type Phase Shifters with High Figure-of-Merit. IEEE Trans. Microw. Theory Tech.
**2015**, 63, 1883–1893. [Google Scholar] [CrossRef] - Cory, R. The Nuts and Bolts of Tuning Varactors; Technical Report; Skyworks Solutions, Inc.: Irvine, CA, USA, 2009; Available online: https://www.highfrequencyelectronics.com/Feb09/HFE0209_Cory.pdf (accessed on 11 August 2022).
- Macom. Solderable GaAs Constant Gamma Flip-Chip Varactor Diode. Available online: https://cdn.macom.com/datasheets/MAVR-000120-1411.pdf (accessed on 11 August 2022).
- Schühler, M.; Schmidt, C.; Weber, J.; Wansch, R.; Hein, M. Phase shifters based on PIN-diodes and varactors: Two concepts by comparison. In Information Technology and Electrical Engineering-Devices and Systems, Materials and Technologies for the Future; Faculty of Electrical and Information Technology, Technische Universität Ilmenau: Ilmenau, Germany, 2009; Volume 51, p. 2006. [Google Scholar]
- Kirillov, V.; Kozlov, D.; Bulja, S. Series vs. Parallel Reflection-Type Phase Shifters. IEEE Access
**2020**, 8, 189276–189286. [Google Scholar] [CrossRef] - Macom. MA4AGP907 MA4AGFCP910. Available online: https://cdn.macom.com/datasheets/MA4AGP907__MA4AGFCP910.pdf (accessed on 11 August 2022).
- Usta, E.; Türker Tokan, N. Effects of Surface Finish Material on Millimeter-Wave Antenna Performance. IEEE Trans. Compon. Packag. Manuf. Technol.
**2019**, 9, 815–821. [Google Scholar] [CrossRef] - Taconic. Advanced PCB Materials Product Selection Guide. Available online: http://www.taconic.co.kr/download/ProductSelectionGuide.pdf (accessed on 19 December 2022).

**Figure 1.**Structure of the $4\times 4$ antenna array. The vertical dimensions are exaggerated for clarity.

**Figure 6.**Single phase shifter simulation results when the voltage is swept from 0 V to 12 V: (

**a**) ${S}_{11}$; and (

**b**) ${S}_{21}$.

**Figure 7.**Antenna with dual polarization control through two individually controlled PIN diodes: (

**a**) antenna; and (

**b**) equivalent circuit of PIN diode in ON and OFF state.

**Figure 8.**Simulation results of a single antenna at broadside: (

**a**) ${S}_{11}$ for both polarizations; and (

**b**) normalized gain at 3 GHz for both polarizations.

**Figure 9.**Fabricated a $4\times 4$ structure without an antenna for phase shift characterization: (

**a**) front side; and (

**b**) back side.

**Figure 11.**Measurement results of the $4\times 4$ structure without an antenna at 3 GHz when varactors are biased from 0 to 12 V: (

**a**) ${S}_{11}$ measurement; (

**b**) ${S}_{21}$ measurement; and (

**c**) unit cell mapping of the $4\times 4$ antenna array.

**Figure 13.**Fabricated $4\times 4$ structure: (

**a**) antenna side; (

**b**) phase shifter and power divider side.

Parameter | Value |
---|---|

${L}_{\mathrm{S}}$ | 1.23 nH |

${C}_{\mathrm{jo}}$ | 1.23 pF |

${V}_{\mathrm{j}}$ | 1.92 V |

m | 2.06 |

${C}_{\mathrm{P}}$ | 0.25 pF |

**Table 2.**Phase measurements to determine the amount of phase error in different unit cells for 10${}^{\circ}$ beam steering case.

Row 3 | Row 4 | ||||||||
---|---|---|---|---|---|---|---|---|---|

Unit Cell | Calculated | Measured | Voltage | Error | Unit Cell | Calculated | Measured | Voltage | Error |

B12 | 0.0${}^{\circ}$ | 0.0${}^{\circ}$ | 4.4 V | 0.0${}^{\circ}$ | B11 | 0.0${}^{\circ}$ | 0.0${}^{\circ}$ | 4.4 V | 0.0${}^{\circ}$ |

B22 | 25.0${}^{\circ}$ | 23.3${}^{\circ}$ | 5.3 V | 1.7${}^{\circ}$ | B21 | 25.0${}^{\circ}$ | 25.3${}^{\circ}$ | 5.3 V | −0.3${}^{\circ}$ |

B32 | 50.0${}^{\circ}$ | 49.2${}^{\circ}$ | 7.0 V | 0.8${}^{\circ}$ | B31 | 50.0${}^{\circ}$ | 50.3${}^{\circ}$ | 7.0 V | −0.3${}^{\circ}$ |

B42 | 75.0${}^{\circ}$ | 75.0${}^{\circ}$ | 12.0 V | 0.0${}^{\circ}$ | B42 | 75.0${}^{\circ}$ | 79.7${}^{\circ}$ | 12.0 V | −4.6${}^{\circ}$ |

**Table 3.**Phase measurements to determine the amount of phase error in different unit cells for 40${}^{\circ}$ beam steering case.

Row 3 | Row 4 | ||||||||
---|---|---|---|---|---|---|---|---|---|

Unit Cell | Calculated | Measured | Voltage | Error | Unit Cell | Calculated | Measured | Voltage | Error |

B12 | 0.0${}^{\circ}$ | 0.0${}^{\circ}$ | 1.9 V | 0.0${}^{\circ}$ | B11 | 0.0${}^{\circ}$ | 0.0${}^{\circ}$ | 1.9 V | 0.0${}^{\circ}$ |

B22 | 92.6${}^{\circ}$ | 97.7${}^{\circ}$ | 2.7 V | −5.2${}^{\circ}$ | B21 | 92.6${}^{\circ}$ | 94.5${}^{\circ}$ | 2.7 V | −1.9${}^{\circ}$ |

B32 | 185.1${}^{\circ}$ | 174.9${}^{\circ}$ | 4.0 V | 10.2${}^{\circ}$ | B31 | 185.1${}^{\circ}$ | 168.8${}^{\circ}$ | 4.0 V | 16.3${}^{\circ}$ |

B42 | 277.7${}^{\circ}$ | 270.5${}^{\circ}$ | 12.0 V | 7.2${}^{\circ}$ | B42 | 277.7${}^{\circ}$ | 269.0${}^{\circ}$ | 12.0 V | 8.7${}^{\circ}$ |

Target Angle | Measured Angle | Angle Error | Control Angle | Peak Gain | SLL |
---|---|---|---|---|---|

${0}^{\circ}$ | ${2}^{\circ}$ | $+{2}^{\circ}$ | ${0}^{\circ}$ | 4.4 dBi | −11.4 dB |

${5}^{\circ}$ | ${5}^{\circ}$ | ${0}^{\circ}$ | ${3}^{\circ}$ | 4.7 dBi | −12.0 dB |

${10}^{\circ}$ | ${11}^{\circ}$ | $+{1}^{\circ}$ | ${5}^{\circ}$ | 4.6 dBi | −11.4 dB |

${15}^{\circ}$ | ${13}^{\circ}$ | $-{2}^{\circ}$ | ${10}^{\circ}$ | 4.6 dBi | −10.6 dB |

${20}^{\circ}$ | ${19}^{\circ}$ | $-{1}^{\circ}$ | ${20}^{\circ}$ | 3.8 dBi | −8.5 dB |

${25}^{\circ}$ | ${23}^{\circ}$ | $-{2}^{\circ}$ | ${30}^{\circ}$ | 3.4 dBi | −7.4 dB |

${30}^{\circ}$ | ${29}^{\circ}$ | $-{1}^{\circ}$ | ${35}^{\circ}$ | 3.4 dBi | −7.2 dB |

${35}^{\circ}$ | ${35}^{\circ}$ | ${0}^{\circ}$ | ${40}^{\circ}$ | 3.1 dBi | −7.6 dB |

${40}^{\circ}$ | ${39}^{\circ}$ | $-{1}^{\circ}$ | ${44}^{\circ}$ | 3.0 dBi | −7.4 dB |

${45}^{\circ}$ | ${43}^{\circ}$ | $-{2}^{\circ}$ | ${45}^{\circ}$ | 2.8 dBi | −7.8 dB |

Parameter | Value |
---|---|

Aperture size | 160 mm × 160 mm |

Ideal Directivity | 15.1 dBi |

Measured gain | 4.4 dBi |

Feed network loss | 0.8 dB |

Phase shifter loss | 0.8 dB |

PIN diode loss | 0.4 dB |

Fabrication tolerance losses | 0.8 dB |

ENIG and conductor loss | 5.8 dB |

Surface roughness | 2.1 dB |

Reference | Peak Gain | Steered Gain (Angle) | Scan Loss | Max Steering Error | Phase Profile | Characterization | Frequency | Array Size | Aperture Efficiency |
---|---|---|---|---|---|---|---|---|---|

[18] | 20.8 dBi | 18.3 dBi (-40${}^{\circ}$) | 2.5 dB | N/A | Discrete | Single, waveguide | 29 GHz | 20 × 20 | 9.5% |

[14] | 17.0 dBi | 14.9 dBi (40${}^{\circ}$) | 2.1 dB | N/A | Continuous | Datasheet ^{1} | 5.4 GHz | 8 × 8 | 28.5% |

[23] | 14.6 dBi | 12.9 dBi (45${}^{\circ}$) | 1.9 dB | N/A | Continuous & Discrete | Datasheet ^{1} | 4.8 GHz | 6 × 6 | 27.6% |

[15] | 15.0 dBi | 13.4 dBi (40${}^{\circ}$) | 1.6 dB | N/A | Continuous | Individual, method unclear | 5.0 GHz | 6 × 6 | 28.2% |

[24] | 13.8 dBi | N/A (60${}^{\circ}$) | 2.8 dB | 0.9${}^{\circ}$ | Discrete | Method unclear | 14.8 GHz | 24 × 2 | 6.3% |

[19] | 16.8 dBi | 14.5 dB (40${}^{\circ}$) | 2.3 dB | N/A | Discrete | Datasheet ^{1} | 5.0 GHz | 16 × 16 | 18.4% |

[16] | 15.6 dBi | 13.4 dB (45${}^{\circ}$) | 2.2 dB | 1.9${}^{\circ}$ | Continuous | Individual, near field probe | 4.8 GHz | 6 × 6 | 34.0% |

[17] | 19.9 dBi | N/A | N/A | 16${}^{\circ}$ | Continuous | Single unit cell | 5.2 GHz | 5 × 5 | N/A |

[25] | 23.7 dBi | 20.0 dBi (−45${}^{\circ}$) | 3.7 dB | N/A | Continuous and discrete | Datasheet ^{1} | 5.6 GHz | 16 × 16 | 33.5% |

[20] | 21.3 dBi | 15.4 dBi (60${}^{\circ}$) | 5.9 dB | N/A | Discrete | Datasheet ^{1} | 28 GHz | 20 × 20 | 12.5% |

[21] | 21.4 dBi | 19.9 dBi (40${}^{\circ}$) | 1.5 dB | N/A | Discrete | Datasheet ^{1} | 13.5 GHz | 16 × 16 | 14.8% |

[22] | 13.4 dBi | 10.7 dBi (45${}^{\circ}$) | 2.7 dB | 0.8${}^{\circ}$ | Discrete | Single, PIN & phase shifter measurement | 12 GHz | 16 × 2 | 24.5% |

This work | 4.7 dBi | 3.0 dBi (40${}^{\circ}$) | 1.7 dB | 2${}^{\circ}$ | Continuous | Measurement, average phase shift | 3 GHz | $4\times 4$ | 8.6% |

2.8 dBi (45${}^{\circ}$) | 1.9 dB |

^{1}Works that only present component values for PIN diodes and/or varactors are marked as datasheet.

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Verho, S.; Nguyen, V.T.; Chung, J.-Y. A 4 × 4 Active Antenna Array with Adjustable Beam Steering. *Sensors* **2023**, *23*, 1324.
https://doi.org/10.3390/s23031324

**AMA Style**

Verho S, Nguyen VT, Chung J-Y. A 4 × 4 Active Antenna Array with Adjustable Beam Steering. *Sensors*. 2023; 23(3):1324.
https://doi.org/10.3390/s23031324

**Chicago/Turabian Style**

Verho, Sebastian, Van Thang Nguyen, and Jae-Young Chung. 2023. "A 4 × 4 Active Antenna Array with Adjustable Beam Steering" *Sensors* 23, no. 3: 1324.
https://doi.org/10.3390/s23031324