Multiband multiple‐input multiple‐output antenna with high isolation for future 5G smartphone applications

Abstract

A multiband high-isolation multiple-input multiple-output (MIMO) antenna using balanced mode and coupled neutralization line (NL) is presented in this article. The balanced modes of dipole and loop antennas, which leads to good isolation intrinsically are used for the 8 × 8 MIMO in the LTE bands 42 (3400-3600 MHz)/Chinese 5G band (3300-3400 and 3400-3600 MHz). The unbalanced mode of loop antennas, which optimized by decoupling structure are designed for the 4 × 4 MIMO in the LTE band 40 (2300-2400 MHz). Therefore, the eight-antenna array is formed by four dipole elements and four loop elements. The simulated and measured results show that the proposed antenna can cover 2300 to 2400 and 3300 to 3600 MHz, with reflection coefficient better than −6 dB and isolation higher than 15 dB. Good radiation performance and low envelope correlation coefficient can also be obtained. Specific absorption rate of user's hand is also discussed in this article. K E Y W O R D S5G smartphone, high isolation, MIMO, neutralization line decoupling, S-SAR | INTRODUCTIONAs the current 4G system can no longer meet the requirements of explosive communication data growth, 1-3 both industry and academia are focusing on realizing fifth generation (5G) communications. It has been proved that multipleinput and multiple-output (MIMO) antenna system can achieve large capacity and higher transmission rate for 5G systems below 6 GHz. [4][5][6][7][8][9][10][11][12][13][14][15][16] In the future, at least eight antenna elements should be integrated into a mobile terminal, which can achieve larger channel capacity and better communication reliability. Because of the trend of bezel-less screen design for cellphones, it is a big challenge to guarantee high isolation when more MIMO antenna elements are implemented in such small design space. 3 As the standard for 5G communication is now being formulated, some MIMO antennas designed for 5G smartphone

A 2 × 1 array‐based wideband mm‐wave antenna integrated with a 2‐element multiple‐input‐multiple‐output antenna for 5G mobile terminals

“…Performance comparison of the proposed design with the newly published works presented in [14][15][16][17][18][19][20] as shown in Table 5 is carried out to make the strength of the proposed design obvious. In terms of size, effective bandwidth, bandwidth, peak gain, ECC, and the potential to support the mm-wave spectrum, the developed model is compared to the listed papers.…”

“…The presented antenna covered the 5G new radio (NR) N77 (3.3-4.2 GHz) band. The recorded antennas in [19][20][21] used only the sub-6 GHz band or below with a relatively narrow bandwidth for 5G applications and all these models did not support mm-wave applications.…”

Effect of Dielectric Substrate on Dipole Antenna Directivity

“…They were able to create a multiband which had a high insolation input and output, which were both multiple in nature, for their antenna [22]. Their antenna specifically utilized a balanced mode and coupled neutralization line.…”

Design and Performance Analysis of a Compact Planar MIMO Antenna for IoT Applications

“…In recent years, a few multiple-input-multiple-output (MIMO) antenna structures for IoT applications have also been reported [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. A triple-band MIMO antenna with a complementary split-ring resonator was presented in [ 23 ].…”

“…A triple-band MIMO antenna with a complementary split-ring resonator was presented in [ 23 ]. A planar multi-band MIMO antenna in [ 24 ], a two-port dielectric resonator antenna structure in [ 25 ], a meander line radiator loaded with a split ring resonator in [ 26 ], an ellipse-shaped multi-band MIMO antenna in [ 27 ], an eight-port meandered line structure in [ 28 ], a four-port MIMO antenna for 5G applications in [ 29 ], a four-port L-shaped planar inverted-F antenna in [ 30 ], a two-port dielectric resonator antenna for LTE applications in [ 31 ], a CPW-fed sickle-shaped resonator for IoT application in [ 32 ], a meander line monopole antenna for multiband applications in [ 33 ], a monopole antenna with vias for IoT applications in [ 34 ], a CPW-fed rectangular patch radiator in [ 35 ], and a combination of simple monopole radiators for IoT/WLAN/sub-6 GHz/X-band applications in [ 36 ]. However, the majority of the above-reported MIMO antenna designs were large in size and difficult to integrate on the printed circuit board of the IoT module.…”