Prof. Dr. Gui Liu

Wenzhou University

Prof. Dr. Gui Liu

Wenzhou University

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Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 February 2021 in Electronics

Journal Article

A Quad-Port Dual-Band MIMO Antenna Array for 5G Smartphone Applications

A quad-port antenna array operating in 3.5 GHz band (3.4–3.6 GHz) and 5 GHz band (4.8–5 GHz) for fifth-generation (5G) smartphone applications is presented in this paper. The single antenna element consists of an L-shaped strip, a parasitic rectangle strip, and a modified Z-shaped strip. To reserve space for 2G/3G/4G antennas, the quad-port antenna array is printed along the two long frames of the smartphone. The evolution design and the analysis of the optimal parameters of a single antenna element are derived to investigate the principle of the antenna. The prototype of the presented antenna is tested and the measured results agree well with the simulation. The measured total efficiency is better than 70% and the isolation is larger than 16.5 dB.

12 July 2021 in Electronics

Journal Article

Design of a MIMO Antenna with High Gain and Enhanced Isolation for WLAN Applications

A multi-input multi-output (MIMO) antenna for wireless local area network (WLAN) applications operating in 2.4 GHz and 5.8 GHz frequency bands is proposed in this paper. The proposed dual-band MIMO antenna is composed of two symmetrical radiation elements, and the isolation performance is improved by adopting parasitic elements and a defective ground plane. The measured reflection coefficients are less than −10 dB in the bandwidth range of 2.12–2.8 GHz and 4.95–6.65 GHz, respectively. The measurements show excellent isolation of −21 dB and −15 dB in both desired frequency bands, respectively. The total peak gain is greater than 4.8 dBi. The calculated envelope correlation coefficients (ECC), based on the measured S-parameters, are smaller than 0.01 and 0.024 in the lower and higher frequency bands, respectively. The dimension of the presented antenna occupies 50 × 40 × 1.59 mm³. It is suitable for IEEE 802.11 a/b/g/n (2.4–2.4835 GHz, 5.15–5.35 GHz and 5.725–5.85 GHz) WLAN applications.

10 May 2021 in Micromachines

Journal Article

A Compact Planar Dual-Band Multiple-Input and Multiple-Output Antenna with High Isolation for 5G and 4G Applications

In this paper, a compact planar dual-band multiple-input and multiple-output (MIMO) antenna with high isolation is presented to satisfy the increasing requirements of wireless communication. The proposed antenna array consists of two identical radiating elements which are fed through micro-strip lines. A rectangular micro-strip stub with defected ground plane is employed to achieve a high isolation which is less than −15 dB between the two antenna elements. The size of the entire MIMO antenna is 32 × 32 × 1.59 mm³, which is printed on an FR4 substrate. The proposed MIMO antenna is optimized to operate in 2.36–2.59 GHz and 3.17–3.77 GHz bands, which can cover the fifth-generation (5G) n7 (2.5–2.57 GHz) and the fourth-generation (4G) Long Term Evolution (LTE) band 42 (3.4–3.6 GHz). The proposed MIMO antenna is feasible for the 5G and 4G applications.

26 April 2021 in Micromachines

Journal Article

Dual-Band MIMO Antenna for 5G/WLAN Mobile Terminals

This paper presents a dual-band four-element multiple-input-multiple-output (MIMO) array for the fifth generation (5G) mobile communication. The proposed antenna is composed of an open-loop ring resonator feeding element and a T-shaped radiating element. The utilization of the open-loop ring resonator not only reduces the size of the antenna element, but also provides positive cross-coupling. The dimension of a single antenna element is 14.9 mm × 7 mm (0.27λ × 0.13λ, where λ is the wavelength of 5.5 GHz). The MIMO antenna exhibits a dual-band feature from 3.3 to 3.84 GHz and 4.61 to 5.91 GHz, which can cover 5G New Radio N78 (3.3–3.8 GHz), 5G China Band N79 (4.8–5 GHz), and IEEE 802.11 ac (5.15–5.35 GHz, 5.725–5.85 GHz). The measured total efficiency and isolation are better than 70% and 15 dB, respectively. The calculated envelope correlation coefficient (ECC) is less than 0.02. The measured results are in good agreement with the simulated results.

9 June 2021 in International Journal of Antennas and Propagation

Journal Article

Two-Port CPW-Fed Dual-Band MIMO Antenna for IEEE 802.11 a/b/g Applications

A coplanar waveguide- (CPW-) fed dual-band multiple-input multiple-output (MIMO) antenna for 2.45/5.5GHz wireless local area network (WLAN) applications is presented in this paper. The presented MIMO antenna consists of two identical trapezoidal radiating elements which are perpendicular to each other. The size of the entire MIMO antenna is 50×50×1.59mm³, which is printed on a FR4 substrate. The measured impedance bandwidth of the proposed antenna is 2.253.15GHz and 4.895.95GHz, which can cover IEEE 802.11 a/b/g frequency bands. A rectangular microstrip stub is introduced to achieve a good isolation which is less than 15dB in both operation frequency bands. The measured peak gain is 5.59dBi at 2.45GHz and 5.63dBi at 5.5GHz. The measured antenna efficiency is 77.8 and 80.4 in the lower and higher frequency bands, respectively. The ECC values at the lower and higher frequencies are lower than 0.003 and 0.01, respectively.

30 December 2022 in Micromachines

Journal Article

Dual-Band MIMO Antenna with Enhanced Isolation for 5G NR Application

A two-port multiple-input and multiple-output (MIMO) antenna with dual-band characteristics operating at the fifth-generation (5G) new radio (NR) sub-6 GHz n7/n38/n41/n79 bands is proposed. The proposed MIMO antenna is composed of two symmetric antenna elements and a defected ground plane. The antenna element consists of an incomplete circular patch with two L-shaped branches. By applying the defected ground structure and the slotted stub, the current distribution on the ground plane is changed to reduce the mutual coupling between the antenna elements. The measured −10 dB reflection coefficients cover 2.34–2.71 GHz and 3.72–5.10 GHz, while the measured isolation is larger than 20 dB at the whole operating frequency band. The paper has investigated different performance parameters in terms of the envelope correction coefficient (ECC), diversity gain (DG), radiation patterns, antenna gain, and efficiency. The proposed MIMO antenna is suitable for 5G applications.

About Me

Gui Liu was born in Wenzhou City, Zhejiang Province, China in 1975. He received a B.S. degree in communication engineering from South China University of Technology, Guangdong, China in 1997, an M.S. degree in electrical engineering from Sun Yat-Sen University, Guangdong, China in 2003 and a PhD degree in Electrical Engineering from Illinois Institute of Technology, Chicago, IL, USA, in 2011. Since Sept. 2011, Dr. Liu has been a professor at Wenzhou University, China. He is currently a full professor and Oujiang Distinguished Professor at the College of Electrical and Electronics at Wenzhou University. He is a deputy director at the department of Science & Technology at Wenzhou University. His research interest includes MIMO antennas, ultra-wideband antennas, multiband antennas, millimeter wave on-chip antennas and passive components and millimeter wave integrated circuit design. He serves as an active reviewer for numerous IEEE, Elsevier, IOP science and other international journals.

Prof. Dr. Gui Liu

Prof. Dr. Gui Liu

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