High‐isolation dual‐port antenna with self‐decoupling characteristics for 5G smartphone applications

Abstract

A dual-port antenna with shared radiator and self-decoupling characteristics is proposed. The feed position of the two ports is asymmetrically arranged for the radiator. The working principle of the proposed dual-port antenna is analyzed by using the equivalent transmission line theory model. The analysis results show that the high isolation characteristic is realized when the two ports of the antenna satisfy a certain layout. The isolation between the two ports of the proposed dual-port antenna is better than 16 dB across the 3.4 $ 3.6GHz. The envelope correlation coefficient is less than 0.042. Based on the dual-port antenna, a set of 8 × 8 MIMO antenna array was designed and measured. The isolation of the proposed 8 × 8 MIMO antenna array is better than 15 dB between all ports, the total efficiency is 38.75% $ 87.5% with an average efficiency 64.58%.

A compact, high isolation building block for 8 × 8 multi‐input multi‐output antenna array suitable for 5G smartphone applications

“…In recent years, many MIMO antenna systems have been reported for mobile communications with acceptable isolation and envelope correlation coefficient (ECC) 6–26 . There are numerous mature decoupling methods available, including the use neutralization line (NL) method, 6–8 defected ground structure (DGS) method, 9–11 polarization diversity technique, 12–19 self‐decoupling, 20,22 using decoupling network, 24,25 and characteristic mode analysis 26 .…”

“…In recent years, many MIMO antenna systems have been reported for mobile communications with acceptable isolation and envelope correlation coefficient (ECC) 6–26 . There are numerous mature decoupling methods available, including the use neutralization line (NL) method, 6–8 defected ground structure (DGS) method, 9–11 polarization diversity technique, 12–19 self‐decoupling, 20,22 using decoupling network, 24,25 and characteristic mode analysis 26 . To validate the NL concept, a vertical metallic patch is added to the antenna, which can effectively suppress the ground plane fringing current as reported in Liu et al 6 To reduce coupling between the designed monopole antenna pair, a 3 mm NL is incorporated between antenna pairs, as reported in Shi et al 7 In Guo et al, 8 a NL helps to reduce mutual coupling between folded monopole antenna and a gap‐coupled loop branch.…”

“…In Sun and Li, 19 a wideband compact open slot antenna is reported with the help of various spatial arrangements, and greater than 10 dB of isolation is achieved. Moreover, works reported in References 20–22 used the self‐decoupling technique to design compact antenna structures without sacrificing isolation. A compact building block is reported in Ren et al 20 which consists of slot and loop antennas having a shared aperture resulting in high isolation (>16 dB).…”

“…Whereas, in Piao et al, 21 the inherent decoupling effect helped to achieve an isolated ground radiation antenna. A dual‐port antenna having a common radiator is analyzed and proposed in Yang et al 22 for the LTE‐42 band, self‐decoupling technique helps to achieve isolation greater than 16 dB. Another way to improve isolation with the help of decoupling networks is in Piao et al, 23 a half‐wavelength additional resonator is incorporated to form a closed‐decoupling loop to maximize the isolation (>15 dB) between the antenna elements.…”