Dual-Functional MIMO Antenna Array With High Isolation for 5G/WLAN Applications in Smartphones

Abstract

A dual-functional antenna array operating in the long term evolution (LTE) band 42 (3.4-3.6 GHz) and 5.8-GHz wireless wide area network (WLAN) band (5.725-5.875 GHz) for multipleinput multiple-output (MIMO) applications in 5G smartphones is proposed. The proposed 8-antenna array is composed of two different antenna elements, namely, the folded L-shaped antenna and couple-fed U-shaped antenna. It can be applied in the 8 × 8 (by using 8 antenna elements) and 4 × 4 (by using 4 antenna elements) MIMO system across the LTE band 42 and 5.8-GHz WLAN band, respectively. The quasi-orthogonal polarization, balanced mode excitation and pattern diversity are properly used to achieve high isolation within the operation bands. A prototype of the proposed antenna array was fabricated and measured. The measured isolations in the LTE band 42 (6-dB impedance matching) and 5.8-GHz WLAN band (10-dB impedance matching) are better than 17.1 dB and 34.6 dB, respectively. The total efficiencies are 45%-62% and 52%-59% in the two operation bands, respectively. Besides, the measured envelope correlation coefficients (ECCs) are less than 0.045 and 0.0001, the calculated peak ergodic channel capacities are 37.9 bps/Hz and 19.3 bps/Hz in the 8 × 8 or 4 × 4 MIMO system across the operation bands. Furthermore, user's hand and head effects are investigated and desirable results are obtained. The above results show that this proposed antenna array is a good candidate for MIMO applications in smartphones.

Minimized Triple-Band Eight-Element Antenna Array for 5G Metal-frame Smartphone Applications

“…However, with the limited internal space of the universal smartphones, the number of antenna elements will be influenced. In order to solve this problem, each antenna element should be minimized [1][2][3][4], and operate at dual-band [5][6][7][8][9][10][11][12] or broadband [13][14][15][16][17]. By sharing a common grounding branch for the two adjacent antenna elements, a compact self-decoupled antenna pair was obtained in [1][2][3].…”

“…Two double-branch monopoles and a T-shaped decoupling stub were utilized for dual-band operation [9]. In [10], two different antenna elements, namely the folded L-shaped antenna and the couple-fed U-shaped antenna, were applied for LTE band 42 and 5.8-GHz WLAN band, respectively. A modified E-shaped strip on the corner of the frame was employed to realize a dual-band MIMO antenna [11].…”

Design of Mimo/Smart Antenna Arrays Using Different Array Modules for Handheld Device

“…Massive MIMO systems in the future mobile device are required to be integrated with 2G/3G/4G and 5G band antennas with different structures in a limited internal space, which raises a challenge to antenna engineers [1]. There have been reports on the design of multi-frequency band antennas, which integrate multiple antenna structures in one space [2][3][4][5][6][7][8][9][10][11]. In [3], an integrated design with MIMO antenna systems for 4G and 5G applications is proposed.…”

A Metasurface-Based Low-Profile Array Decoupling Technology to Enhance Isolation in MIMO Antenna Systems

“…Consequently, the mutual coupling between MIMO array elements fiercely increases, while the radiation capability [4] and data throughput [5] of the array are seriously affected. As a result, it is necessary to reduce the mutual coupling between antennas as much as possible [6], especially in compact arrays. Many decoupling techniques have attracted attention in academia and industry, not only the method to increase the physical separation of elements.…”