# Design and Investigation of Modern UWB-MIMO Antenna with Optimized Isolation

^{1}

^{2}

^{3}

^{4}

^{5}

^{*}

## Abstract

**:**

^{3}. The $\left|{S}_{11}\right|$and voltage standing wave ratio (VSWR) of the proposed antenna are less than −10 dB and 2, respectively, in the range of 3–40 GHz. The total impedance bandwidth of the proposed design is 37 GHz. The VSWR, $\left|{S}_{11}\right|$, $\left|{S}_{22}\right|$, $\left|{S}_{21}\right|$, $\left|{S}_{12}\right|$, gain, envelope correlation coefficient (ECC), radiation pattern, and various other characteristic parameters are discussed in detail. The proposed antenna is optimized and simulated in a computer simulation technology (CST) studio, and printed on a FR4 substrate.

## 1. Introduction

## 2. Related Literature

^{2}, where the impedance bandwidth was 38.7 GHz, ranging from 1.3 to 40 GHz, and the isolation (<−20 dB) was increased through a T-shaped stub. The DG of the presented MIMO antenna was 10 dB, ECC was less than 0.02, and efficiency was greater than 80%. In [32], authors presented coplanar waveguide (CPW)-fed SWB-MIMO antenna with a large size of $63\times 63$mm

^{2}, and the impedance bandwidth achieved is 38.7 GHz, starting from 1.3 to 40 GHz. The peak gain of the presented antenna is 5.5 dBi, the isolation is less than −16 dB, and ECC is less than 0.01. In [33], a MIMO antenna as presented with a dimension of $45\times 45$ mm

^{2}, and $\left|{S}_{11}\right|$ was less than −10 dB in an operating range of 2.2 to 13.5 GHz, with a total impedance bandwidth of 11.3 GHz. The gain of the proposed design was 6.8 dBi, isolation was less than −18 dB, and was less than 0.01. The authors of [34] presented a UWB-MIMO antenna with a shared ground; the overall size of the antenna was $28.5\times 28.5$mm

^{2}, and a high isolation was achieved with the help of an I-shaped stub between radiators. The total impedance bandwidth of the antenna was 8.42 GHz between 2.66 and 11.08 GHz. The peak gain of the proposed MIMO antenna was 3.5 dBi, isolation was less than −15 dB, and ECC was less than 0.01. In [35], authors proposed a hexagonal-shaped MIMO antenna of a very large size ($28\times 56$ mm

^{2}), isolation was achieved using parasitic elements and tree distinct-shaped stubs, and the impedance bandwidth was 11.3 GHz in a range of 2 GHz to 13.3 GHz. The diversity gain was less than 9.985 dBi, ECC was less than 0.04, peak gain was 6.6 dBi, and variable radiation efficiency was between 78% to 94%.

^{2}; the impedance bandwidth was 13 GHz starting from 3 to 16 GHz, the ECC was less than 0.01, peak gain was 6 dBi, and isolation was less than −16 dB. In [42], a circular-shaped MIMO antenna with a size of $64\times 45$mm

^{2}was presented; the isolation was increased with a decoupling stub, and the impedance bandwidth was 8.5, ranging from 2.5 to 11 GHz. The gain of the proposed antenna was 6 dBi, the ECC was less than 0.02, and isolation was less than −15 dB. Various transmitters and receivers have also been designed for impulse radio UWB systems [43,44,45]. A detailed comparison between existing and proposed antennas are summarized in Table 1.

## 3. Antenna Design and Characterization

#### 3.1. Antenna Design

#### 3.2. Decoupling Stub

## 4. Results and Discussion

## 5. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

- See, T.S.P.; Chen, Z.N. An ultrawideband diversity antenna. IEEE Trans. Antennas Propag.
**2009**, 57, 1597–1605. [Google Scholar] [CrossRef] - Khan, M.I.; Khattak, M.I.; Witjaksono, G.; Barki, Z.U.; Ullah, S.; Khan, I.; Lee, B.M. Experimental Investigation of a Planar Antenna with Band Rejection Features for Ultra-Wide Band (UWB) Wireless Networks. Int. J. Antennas Propag.
**2019**, 2019, 11. [Google Scholar] [CrossRef] - Khattak, M.I.; Khan, M.I.; Ullah, Z.; Ahmad, G.; Khan, A. Hexagonal Printed Monopole Antenna with Triple Stop Bands for UWB Applications. Mehran Univ. Res. J. Eng. Technol. Pak.
**2019**, 38, 335–340. [Google Scholar] [CrossRef] [Green Version] - Zhang, X.; Ur Rahman, S.; Cao, Q.; Gil, I. A Novel SWB Antenna with Triple Band-Notches Based on Elliptical Slot and Rectangular Split Ring Resonators. Electron. J.
**2019**, 8, 1–17. [Google Scholar] [CrossRef] - Khan, M.I.; Rahman, S.; Khan, M.K.; Saleem, M. A Dual Notched Band Printed Monopole Antenna for Ultra Wide Band Applications. In Proceedings of the 2016 Progress in Electromagnetics Research (PIERS), Shanghai, China, 8–11 August 2016; pp. 4390–4393. [Google Scholar]
- Khan, M.K.; Khan, M.I.; Ahmad, I.; Saleem, M. Design of a Printed Monopole Antenna with Ridged Ground for Ultra Wide Band Applications. In Proceedings of the 2016 Progress in Electromagnetics Research (PIERS), Shanghai, China, 8–11 August 2016; pp. 4394–4396. [Google Scholar]
- Rahman, S.U.; Cao, Q.; Ullah, H.; Khalil, H. Compact design of trapezoid shape monopole antenna for SWB application. Microw. Opt. Technol. Lett.
**2019**, 61, 1931–1937. [Google Scholar] [CrossRef] - Li, M.; Luk, K.M. A differential-fed UWB antenna element with unidirectional radiation. IEEE Trans. Antennas Propag.
**2016**, 64, 3651–3656. [Google Scholar] [CrossRef] - Ren, J.; Hu, W.; Yin, Y.; Fan, R. Compact printed MIMO antenna for UWB applications. IEEE Antennas Wirel. Propag. Lett.
**2014**, 13, 1517–1520. [Google Scholar] - Zheng, L.; Tse, D.N.C. Diversity and multiplexing: A fundamental tradeoff in multiple-antenna channels. IEEE Trans. Inf. Theory.
**2003**, 49, 1073–1096. [Google Scholar] [CrossRef] [Green Version] - Rajagopalan, A.; Gupta, G.; Konanur, A.S.; Hughes, B.; Lazzi, G. Increasing channel capacity of an ultrawideband MIMO system using vector antennas. IEEE Trans. Antennas Propag.
**2007**, 55, 2880–2887. [Google Scholar] [CrossRef] - Najam, A.I.; Duroc, Y.; Tedjni, S. UWB-MIMO antenna with novel stub structure. Prog. Electromagn. Res.
**2011**, 19, 245–257. [Google Scholar] [CrossRef] [Green Version] - Iqbal, A.; Saraereh, O.A.; Ahmad, A.W.; Bashir, S. Mutual coupling reduction using F-shaped stubs in UWB-MIMO antenna. IEEE Access.
**2018**, 6, 2755–2759. [Google Scholar] [CrossRef] - Khan, M.S.; Shafique, M.F.; Capobianco, A.D.; Autizi, E.; Shoaib, I. Compact UWB-MIMO antenna array with a novel decoupling structure. In Proceedings of the 2013 10th International Bhurban Conference on Applied Sciences & Technology (IBCAST), Islamabad, Pakistan, 15–19 January 2013; pp. 347–350. [Google Scholar]
- Jabire, A.; Zheng, H.X.; Abdu, A.; Song, Z. Characteristic mode analysis and design of wide band MIMO antenna consisting of metamaterial unit cell. Electronics
**2019**, 8, 68. [Google Scholar] [CrossRef] [Green Version] - Iqbal, A.; A Saraereh, O.; Bouazizi, A.; Basir, A. Metamaterial-based highly isolated MIMO antenna for portable wireless applications. Electronics
**2018**, 7, 267. [Google Scholar] [CrossRef] [Green Version] - Malekpour, N.; Honarvar, M.A. Design of high-isolation compact MIMO antenna for UWB application. Prog. Electromagn. Res. C
**2016**, 62, 119–129. [Google Scholar] [CrossRef] [Green Version] - Li, W.; Hei, Y.; Grubb, P.M.; Shi, X.; Chen, R.T. Compact inkjet-printed flexible MIMO antenna for UWB applications. IEEE Access
**2018**, 6, 50290–50298. [Google Scholar] [CrossRef] - Ibrahim, A.A.; Abdalla, M.A.; Abdel-Rahman, A.B.; Hamed, H.F. Compact MIMO antenna with optimized mutual coupling reduction using DGS. Int. J. Microw. Wirel. Technol.
**2014**, 6, 173–180. [Google Scholar] [CrossRef] - Ali, W.A.; Ibrahim, A.A. A compact double-sided MIMO antenna with an improved isolation for UWB applications. Aeu-Int. J. Electron. Commun.
**2017**, 82, 7–13. [Google Scholar] [CrossRef] - Toktas, A.; Akdagli, A. Compact multiple-input multiple-output antenna with low correlation for ultra-wide-band applications. Iet Microw. Antennas Propag.
**2015**, 9, 822–829. [Google Scholar] [CrossRef] - Zhao, Y.; Zhang, F.S.; Cao, L.X.; Li, D.H. A Compact Dual Band-Notched MIMO Diversity Antenna for UWB Wireless Applications. Prog. Electromagn. Res.
**2019**, 89, 161–169. [Google Scholar] [CrossRef] [Green Version] - Azarm, B.; Nourinia, J.; Ghobadi, C.; Majidzadeh, M.; Hatami, N. A Compact WiMAX Band-Notched UWB MIMO Antenna with High Isolation. Radioengineering
**2018**, 27, 983–989. [Google Scholar] [CrossRef] - Li, W.T.; Hei, Y.Q.; Subbaraman, H.; Shi, X.W.; Chen, R.T. Novel printed filtenna with dual notches and good out-of-band characteristics for UWB-MIMO applications. IEEE Microw. Wirel. Compon. Lett.
**2016**, 26, 765–767. [Google Scholar] [CrossRef] - Liu, L.; Cheung, S.W.; Yuk, T.I. Compact MIMO antenna for portable UWB applications with band-notched characteristic. IEEE Trans. Antennas Propag.
**2015**, 63, 1917–1924. [Google Scholar] [CrossRef] - Biswal, S.P.; Das, S. A low profile dual port UWB-MIMO/diversity antenna with band rejection ability. Int J. RF Microw Comput Aided Eng.
**2017**, 28, e21159. [Google Scholar] [CrossRef] - Gurjar, R.; Upadhyay, D.K.; Kanaujia, B.K.; Sharma, K. A novel compact self-similar fractal UWB MIMO antenna. Int. J. Rf Microw. Comput. Aided Eng.
**2019**, 29, e21632. [Google Scholar] [CrossRef] - Mathur, R.; Dwari, S. A compact UWB-MIMO with dual grounded CRR for isolation improvement. Int. J. Rf Microw. Comput. Aided Eng.
**2019**, 29, e21500. [Google Scholar] [CrossRef] [Green Version] - Tiwari, R.N.; Singh, P.; Kanaujia, B.K. A compact UWB MIMO antenna with neutralization line for WLAN/ISM/mobile applications. Int. J. Rf Microw. Comput. Aided Eng.
**2019**, 29, e21907. [Google Scholar] [CrossRef] - Srivastava, K.; Kumar, A.; Kanaujia, B.K.; Dwari, S.; Kumar, S. A CPW-fed UWB MIMO antenna with integrated GSM band and dual band notches. Int. J. Rf Microw. Comput. Aided Eng.
**2019**, 29, e21433. [Google Scholar] [CrossRef] [Green Version] - Ullah, H.; Rahman, S.U.; Cao, Q.; Khan, I.; Ullah, H. Design of SWB MIMO Antenna with Extremely Wideband Isolation. Electronics
**2020**, 9, 194. [Google Scholar] [CrossRef] [Green Version] - Kumar, P.; Urooj, S.; Alrowais, F. Design of quad-port MIMO/Diversity antenna with triple-band elimination characteristics for super-wideband applications. Sensors
**2020**, 20, 624. [Google Scholar] [CrossRef] [Green Version] - Kumar, P.; Urooj, S.; Malibari, A. Design of Quad-Port Ultra-Wideband Multiple-Input-Multiple-Output Antenna with Wide Axial-Ratio Bandwidth. Sensors
**2020**, 20, 1174. [Google Scholar] [CrossRef] [Green Version] - Liu, Y.F.; Wang, P.; Qin, H. Compact ACS-fed UWB antenna for diversity applications. Electron. Lett.
**2014**, 50, 1336–1338. [Google Scholar] [CrossRef] - Addepalli, T.; Anitha, V.R. Design and Parametric Analysis of Hexagonal Shaped MIMO Patch Antenna for S-Band, WLAN, UWB and X-Band Applications. Prog. Electromagn. Res.
**2019**, 97, 227–240. [Google Scholar] [CrossRef] [Green Version] - Liu, L.; Cheung, S.W.; Yuk, T.I. Compact MIMO antenna for portable devices in UWB applications. IEEE Trans. Antennas Propag.
**2013**, 61, 4257–4264. [Google Scholar] [CrossRef] [Green Version] - Tu, Z.H.; Li, W.A.; Chu, Q.X. Single-layer differential CPW-fed notch-band tapered-slot UWB antenna. IEEE Antennas Wirel. Propag. Lett.
**2014**, 13, 1296–1299. [Google Scholar] - Khan, M.S.; Capobianco, A.D.; Naqvi, A.; Shafique, M.F.; Ijaz, B.; Braaten, B.D. Compact planar UWB MIMO antenna with on-demand WLAN rejection. Electron. Lett.
**2015**, 51, 963–964. [Google Scholar] - Tang, Z.; Wu, X.; Zhan, J.; Hu, S.; Xi, Z.; Liu, Y. Compact UWB-MIMO antenna with high isolation and triple band-notched characteristics. IEEE Access
**2019**, 7, 19856–19865. [Google Scholar] [CrossRef] - Gotra, S.; Varshney, G.; Pandey, V.S.; Yaduvanshi, R.S. Super-wideband multi-input–multi-output dielectric resonator antenna. Iet Microw. Antennas Propag.
**2019**, 14, 21–27. [Google Scholar] [CrossRef] - Kumar, A.; Ansari, A.Q.; Kanaujia, B.K.; Kishor, J.; Tewari, N. Design of triple-band MIMO antenna with one band-notched characteristic. Prog. Electromagn. Res.
**2018**, 86, 41–53. [Google Scholar] [CrossRef] [Green Version] - Jaglan, N.; Gupta, S.D.; Thakur, E.; Kumar, D.; Kanaujia, B.K.; Srivastava, S. Triple band notched mushroom and uniplanar EBG structures based UWB MIMO/Diversity antenna with enhanced wide band isolation. Aeu Int. J. Electron. Commun.
**2018**, 90, 36–44. [Google Scholar] [CrossRef] - Tatsis, G.; Votis, C.; Raptis, V.; Christofilakis, V.; Chronopoulos, S.K.; Kostarakis, P. Design and Implementation of Ultra-Wideband Impulse Radio Transmitter. In AIP Conference Proceedings; American Institute of Physics: Thessaloniki, Greece, 2010; Volume 1203, pp. 579–584. [Google Scholar]
- Angelis, C.T.; Chronopoulos, S.K. System performance of an LTE MIMO downlink in various fading environments. In International Conference on Ambient Media and Systems; Springer: Berlin/Heidelberg, Germany, 2011; pp. 36–43. [Google Scholar]
- Tatsis, G.; Votis, C.; Raptis, V.; Christofilakis, V.; Chronopoulos, S.K.; Kostarakis, P. Performance of UWB-Impulse Radio Receiver Based on Matched Filter Implementation with Imperfect Channel Estimation. In AIP Conference Proceedings; American Institute of Physics: Thessaloniki, Greece, 2010; Volume 1203, pp. 573–578. [Google Scholar]
- Zheng, J.; Li, Y.; Feng, Z. Impact of mutual coupling and polarization of antennas on BER performances of spatial multiplexing MIMO systems. Int. J. Antennas Propag.
**2012**, 2012, 12. [Google Scholar] [CrossRef] [Green Version] - Blanch, S.; Romeu, J.; Corbella, I. Exact representation of antenna system diversity performance from input parameter description. Electron. Lett.
**2003**, 39, 705–707. [Google Scholar] [CrossRef] [Green Version]

**Figure 3.**Design evaluation of decoupling stub in proposed MIMO antenna. (

**a**) MIMO Ant1; (

**b**) MIMO Ant2; and (

**c**) MIMO Ant3.

**Figure 5.**Surface current distribution of proposed MIMO antenna at (

**a**) 5 GHz with decoupling stub (

**b**) 5 GHz without decoupling stub (

**c**) 10 GHz with decoupling stub (

**d**) 10 GHz without decoupling stub (

**e**) 15 GHz with decoupling stub (

**f**) 15 GHz without decoupling stub.

Ref. | Year | Size (mm × mm) | Resonance Freq: Range (GHz) | BW:1 | % BW | BDR |
---|---|---|---|---|---|---|

[1] | 2009 | $45\times 37$ | 3.1–5 | 1.61 | 47 | 264.36 |

[12] | 2011 | $40\times 68$ | 3.2–10.6 | 3.31 | 107.24 | 346.52 |

[13] | 2018 | $50\times 30$ | 2.5–14.5 | 5.8 | 141.17 | 1355.23 |

[14] | 2013 | $27\times 47$ | 3.1–10.6 | 3.41 | 109.50 | 808.11 |

[15] | 2019 | $40\times 80$ | 4.5–8 | 1.78 | 56 | 77.77 |

[17] | 2016 | $26\times 31$ | 2.9–12 | 4.13 | 122.14 | 1621.69 |

[18] | 2018 | $22\times 31$ | 2.9–12 | 4.13 | 122.14 | 1916.55 |

[20] | 2017 | $40\times 40$ | 3.1–11 | 3.54 | 112 | 655.56 |

[21] | 2015 | $26\times 55$ | 3.1–12.3 | 3.96 | 119.5 | 782.62 |

[22] | 2019 | $26\times 28$ | 2.9–10.8 | 3.72 | 115.32 | 1695.19 |

[23] | 2018 | $25\times 38$ | 2.2–10.8 | 4.8 | 141 | 2759.89 |

[24] | 2016 | $35\times 68$ | 3.1–10.65 | 3.43 | 109.89 | 432.41 |

[25] | 2015 | $22\times 36$ | 3.1–11 | 3.54 | 112 | 1324.37 |

[26] | 2017 | $30\times 30$ | 3.08–10.98 | 3.56 | 112.37 | 1184.53 |

[27] | 2019 | $24\times 32$ | 3.1–12.5 | 4.03 | 120.51 | 1469.53 |

[28] | 2019 | $20\times 34$ | 3.1–11 | 3.54 | 112 | 1542.51 |

[29] | 2019 | $21\times 34$ | 3.62–9.35 | 2.58 | 88.35 | 849.83 |

[30] | 2019 | $36\times 45$ | 3.01–12.5 | 4.15 | 122.37 | 750.35 |

Proposed | 2020 | $18\times 36$ | 3–40 | 13.33 | 172.1 | 2655.86 |

Parameter | Value (mm) | Parameter | Value (mm) |
---|---|---|---|

$W$ | 36 | $r$ | 4.4 |

$L$ | 18 | ${r}_{1}$ | 3.5 |

${l}_{f}$ | 5.7 | ${r}_{2}$ | 2 |

${l}_{r}$ | 3.6 | ${r}_{3}$ | 9.5 |

${l}_{g}$ | 4.5 | $d$ | 21.5 |

${w}_{f}$ | 1.2 | ${d}_{1}$ | 1 |

${w}_{r}$ | 6 | $C$ | 1.4 |

© 2020 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 (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Irshad Khan, M.; Khattak, M.I.; Rahman, S.U.; Qazi, A.B.; Telba, A.A.; Sebak, A.
Design and Investigation of Modern UWB-MIMO Antenna with Optimized Isolation. *Micromachines* **2020**, *11*, 432.
https://doi.org/10.3390/mi11040432

**AMA Style**

Irshad Khan M, Khattak MI, Rahman SU, Qazi AB, Telba AA, Sebak A.
Design and Investigation of Modern UWB-MIMO Antenna with Optimized Isolation. *Micromachines*. 2020; 11(4):432.
https://doi.org/10.3390/mi11040432

**Chicago/Turabian Style**

Irshad Khan, Muhammad, Muhammad Irfan Khattak, Saeed Ur Rahman, Abdul Baseer Qazi, Ahmad Abdeltawab Telba, and Abdelrazik Sebak.
2020. "Design and Investigation of Modern UWB-MIMO Antenna with Optimized Isolation" *Micromachines* 11, no. 4: 432.
https://doi.org/10.3390/mi11040432