Co-Located Self-Neutralized Handset Antenna Pairs With Complementary Radiation Patterns for 5G MIMO Applications

Abstract

In this paper, 4 × 4 / 8 × 8 / 10 × 10 multiple input multiple output (MIMO) antenna systems composed of co-located self-neutralized antenna pairs are proposed to operate at 4.8-5.0 GHz (part of N77 band) for the fifth-generation (5G) communication applications. The proposed antenna pairs consist of a loop antenna and a monopole antenna, co-locating together with a compact size of 6.7 × 15.5 × 3.08 mm 3 . Meanwhile, the co-located design can miniaturize 50% of the antenna size, which is quite significant for practical mobile applications with limited space environment. In addition, the adoption of the self-neutralization technique between the co-located loop antenna and the monopole antenna contributes to a satisfactory isolation with better than 25 / 20 / 16.5 dB for the 4 × 4 / 8 × 8 / 10 × 10 MIMO systems respectively. Analysis of the isolation improvement is also discussed in this study. Moreover, the antenna pairs are able to generate complementary radiation patterns, enabling the envelope correlation coefficients (ECC) between the antennas to be less than 0.1. Also, efficiencies of the MIMO antenna system achieve up to 60% as there is no external decoupling structure deteriorating the radiation performance of the proposed antenna pairs. Finally, a 4 × 4 MIMO antenna system prototype is fabricated and measured to verify its prospect for 5G MIMO applications.

Eight‐element self‐decoupled MIMO antenna design for 5G smartphones

“…Many decoupling techniques with specific structures have been proposed in 5G communication such as the decoupling network, 3 neutralization line, 4‐7 multimode decoupling, 8 and electromagnetic bandgap structure 9,10 . Above methods can effectively improve antenna isolation, yet some of the complex decoupling structures occupies much space and will course amounts of deterioration in radiation which leads to low antenna efficiency (>30% in Reference 7, >38% in Reference 8, e.g.…”

A Compact and Straightforward Self-Decoupled MIMO Antenna System for 5G Applications

“…With the allocation of the 3.5 GHz (3.4-3.6 GHz) band for 5G wireless communication [5], the sub-6 GHz MIMO antenna systems have been popularly studied to allow more antenna elements to be integrated into space-scarce terminal devices [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. It has been demonstrated that high isolation (i.e., low mutual coupling) and low correlation are essential figure-of-merits for MIMO antenna systems to guarantee excellent radiation performance and diversity property.…”

“…In the literature, the previously reported techniques for the sub-6 GHz 5G MIMO antennas can be categorized into the following two categories: decoupled MIMO antenna arrays by utilizing decoupling structures [6][7][8][9][10][11][12] and selfdecoupled MIMO antenna arrays without any additional structures [13][14][15][16][17][18][19][20][21][22][23]. For the decoupled MIMO antenna arrays, the frequently adopted decoupling structures include neutralization lines or decoupling networks [6][7][8][9], and additional resonators [9][10][11][12], which require additional occupation and complicated tuning efforts.…”

“…For the decoupled MIMO antenna arrays, the frequently adopted decoupling structures include neutralization lines or decoupling networks [6][7][8][9], and additional resonators [9][10][11][12], which require additional occupation and complicated tuning efforts. On the contrary, the self-decoupled MIMO antenna arrays can achieve adequate isolation by proper arrangement [13][14][15][16][17] and polarization or pattern control [18][19][20][21][22][23], circumventing the case-by-case implementation of extra decoupling structures. However, some of them require vast distances between each two antenna elements [13][14][15][16][17], which severely limit the scale of the integrated antennas; in contrast, others suffer from structural complexity, implementation difficulty, or constrained position requirements.…”

Isolated Ground-Radiation Antenna With Inherent Decoupling Effect and its Applications in 5G MIMO Antenna Array

“…It is of such great interest yet a significant challenge to design MIMO antenna systems with high integration, miniaturized volume, low interference, and low correlation; this is especially true in terminal devices due to size limitation and placement constraint. In the literature, the most recent studies focused on the realization of selfdecoupled compact MIMO antenna sets using polarization or pattern control and on their duplication for the sake of N × N MIMO arrays [4][5][6][7][8][9][10][11][12][13][14][15]; otherwise, other research investigated decoupled MIMO antenna arrays by introducing decoupling structures [16][17][18][19][20][21][22], while the rest relies on the spatial distance to realize optimized arrangement of the MIMO antenna arrays [23][24][25][26][27][28][29][30]. These methods usually suffer from complicated installment, massive structures, or relatively large separations between antenna elements.…”