Eight‐port orthogonally dual‐polarised MIMO antennas using loop structures for 5G smartphone

Abstract

An eight‐port antenna array designed for future 5G 2.6 GHz band (2550–2650 MHz) for multi‐input multi‐output (MIMO) in the smartphone applications is presented. In order to enhance the port isolation and reduce correlation between antennas, square loop radiating strip with orthogonal polarisation is employed. The proposed antenna array is composed of four pairs of uniform antenna elements that are symmetrically placed at the four corners of the main board, and each antenna pair includes a communal square loop and two independently coupled feeding strips. By exciting the square loop from the two feeding strips, respectively, two orthogonally polarised waves are generated. Thus, four horizontally polarised and four vertically polarised antennas are achieved in total. Due to this feature, coupling between antenna pairs is reduced and the MIMO performances are enhanced. A prototype of the proposed antenna array was fabricated, and the experimental results show good impedance matching and acceptable isolation measured across the bands of interest. The MIMO performances such as envelope correlation coefficient, mean effective gain, multiplexing efficiency and channel capacity are also calculated. Besides, simulations of the antenna shifted to 3.5 GHz are also performed. The consistent performances indicate that the proposed structure has good scalability and is promising for future 5G smartphone applications.

Compact eight‐port MIMO/diversity antenna with band rejection characteristics

“…A small‐size four‐element MIMO antenna with the WLAN notched‐band was presented for UWB applications in Reference , where stub elements and EBG were introduced in the antenna configuration to increase interelement isolation. An antenna array comprised of four pairs of identical antenna elements and a square loop radiating strip was proposed for smartphone applications . An eight‐port MIMO configuration with cylindrical dielectric resonator antennas (cDRAs) was reported for wireless access point systems .…”

“…A number of MIMO antenna designs with two, four, and eight radiating elements have been reported in the last few years. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, there was always a trade-off of antenna dimensions, isolation, resonating range, radiation characteristics, and complexity in all of these presented designs and techniques.…”

Slot antenna array for fifth generation metal frame mobile phone applications

“…There are many MIMO antennas for 5G mobile phones, such as slot antennas, monopole antennas and loop antennas . Eight or more antenna elements for 5G mobile phones are located at the two long sides, corners or at the corners and the two long sides simultaneously. When the antenna elements for 5G are located at the corners, they will influence the main antenna and the sub antenna for 2G/3G/4G.…”

“…The antennas in ref. [] are not suitable and applicable for mobile phones with metal frames. To the best of our knowledge, there are not eight or more antenna elements located at the two long sides, which are suitable for real 5G metal frame mobile phone applications.…”

D esign of 8 × 8 dual‐band MIMO antenna array for 5 G smartphone applications

“…Nevertheless, even though other reported works in Refs. have yielded desirable results with different massive MIMO antenna array designs for smartphones applications, these MIMO antennas rarely support the LTE band 46, which is a promising spectrum for future 5G multi‐band smartphone applications.…”