A dual-polarized hybrid eight-antenna array operating in the 2.6-GHz band (2550–2650 MHz) for 5G communication multi-input multi-output (MIMO) operation in the smartphone is presented. The proposed hybrid antenna array elements are symmetrically placed along the long edges of the smartphone, and they are composed of two different four-antenna array types (C-shaped coupled-fed and L-shaped monopole slot) that exhibit orthogonal polarization. Therefore, coupling between the two antenna array types can be reduced, and the MIMO system performances are enhanced. A prototype of the proposed eight-antenna array is manufactured and measured. A good impedance matching (10 dB return loss or better), desirable cross-polarization discrimination (better than 15 dB), and an acceptable isolation (better than 12.5 dB) are obtained. Envelope correlation coefficient and channel capacity are also calculated to evaluate the MIMO performances of the proposed antenna array.

Eight-Port Orthogonally Dual-Polarized Antenna Array for 5G Smartphone Applications

A compact two-antenna building block for forming the multiple-input multiple-output (MIMO) array in the mobile device such as the smartphone is presented. The building block has a planar structure of small size $7 \times 10$ mm2 (about $0.08\lambda \times 0.12\lambda$ ) for operating at 3.5-GHz band (3.4–3.6 GHz), which is the recently identified frequency spectrum in World Radiocommunication Conference 2015 for future broadband mobile services. The building block is formed by two gap-coupled loop antennas having asymmetrically mirrored (AM) structures with respect to the system ground plane of the smartphone. The two AM antennas show good isolation thereof and their envelope correlation coefficient is much less than 0.1 in the operating band, showing very good independence of the two antennas in their far-field radiation characteristics. By using four such building blocks, an eight-antenna MIMO array at 3.5-GHz band in the smartphone is easily implemented. The channel capacity of the eight-antenna MIMO array in an $8 \times 8$ MIMO system is calculated to be about 36 b/s/Hz with 20-dB signal-to-noise ratio. The measured channel capacity obtained using an $8 \times 8$ MIMO measurement setup is also presented, which generally agrees with the calculated results. The obtained eight-antenna MIMO array is promising for future or fifth-generation smartphone applications.

Two Asymmetrically Mirrored Gap-Coupled Loop Antennas as a Compact Building Block for Eight-Antenna MIMO Array in the Future Smartphone

An antenna element that has not only the self-isolated property but also a compact size is proposed for the fifth-generation multiple-input and multiple-output (MIMO) system in mobile phone applications. In particular, the size reduction is done by introducing two vertical stubs into the original self-isolated antenna element. It is demonstrated that very good isolation and antenna efficiency for an 8-antenna MIMO system can be obtained without using any additional isolation elements or decoupling techniques. An antenna prototype is fabricated and measured; and a quite good agreement between simulation and measurement is obtained.

Size Reduction of Self-Isolated MIMO Antenna System for 5G Mobile Phone Applications

A 12-port antenna array operating in the long term evolution (LTE) band 42 (3400–3600 MHz), LTE band 43 (3600–3800 MHz), and LTE band 46 (5150–5925 MHz) for 5G massive multiple-input multiple-output (MIMO) applications in mobile handsets is presented. The proposed MIMO antenna is composed of three different antenna element types, namely, inverted $\pi $ -shaped antenna, longer inverted L-shaped open slot antenna, and shorter inverted L-shaped open slot antenna. In total, eight antenna elements are used for the $8 \times 8$ MIMO in LTE bands 42/43, and six antenna elements are designed for the $6 \times 6$ MIMO in LTE band 46. The proposed antenna was simulated, and a prototype was fabricated and tested. The measured results show that the LTE bands 42/43/46 are satisfied with reflection coefficient better than −6 dB, isolation lower than −12 dB, and total efficiencies of higher than 40%. In addition to that, the proposed antenna array has also shown good MIMO performances with an envelope correlation coefficient lower than 0.15, and ergodic channel capacities higher than 34 and 26.5 b/s/Hz in the LTE bands 42/43 and LTE band 46, respectively. The hand phantom effects are also investigated, and the results show that the proposed antenna array can still exhibit good radiation and MIMO performances when operating under data mode and read mode conditions.

12-Port 5G Massive MIMO Antenna Array in Sub-6GHz Mobile Handset for LTE Bands 42/43/46 Applications

A multi-band 10-antenna array working at the sub-6-GHz spectrum (LTE bands 42/43 and LTE band 46) for massive multiple-input multiple-output (MIMO) applications in future 5G smartphones is proposed. To realize $10\times 10$ MIMO applications in three LTE bands, 10 T-shaped coupled-fed slot antenna elements that can excite dual resonant modes are integrated into a system circuit board. Spatial and polarization diversity techniques are implemented on these elements so that the improved isolation and mitigated coupling effects can be achieved. The proposed antenna array was manufactured and experimentally measured. Desirable antenna efficiencies of higher than 42% and 62% were measured in the low band and high band, respectively. Vital results, such as the envelope correlation coefficient, channel capacity, and mean effective gain ratio, have also been computed and analyzed. The calculated ergodic channel capacities of the $10\times 10$ MIMO system working in the LTE bands 42/43 and LTE band 46 reached up to 48 and 51.4 b/s/Hz, respectively.

Multiband 10-Antenna Array for Sub-6 GHz MIMO Applications in 5-G Smartphones

A new printed MIMO system with eight elements for a 5G mobile terminal is investigated. The MIMO system consists of printed planar inverted-F antenna elements operating at GSM1900 (1880-1920 MHz), LTE2300 (2300-2400 MHz) and LTE2500 (2540-2620 MHz). The antenna elements have a compact size of 14 mm × 15 mm and are deployed on the non-metalised part of a PCB with dimensions 136 mm × 68.8 mm × 1 mm. By only utilising radiation pattern diversity, good isolations and envelope correlation coefficients for both MIMO systems are achieved. The mean effective gains of the antenna elements are also presented.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/el.2015.3960

Printed eight-element MIMO system for compact and thin 5G mobile handest

Three types of compact MIMO (Multiple-Input Multiple-Output) antenna systems with four and six elements for mobile handsets are studied in this paper. The MIMO antenna system is built on a FR4 substrate of the dimensions 136 mm × 68.8 mm × 1 mm. The antenna element is a folded planar inverted-F antenna with added resonating branches wound on a small dielectric cube of the dimensions 10 mm × 10 mm × 5 mm, which is the smallest volume so far reported covering the frequency bands 1880 MHz–1920 MHz and 2300 MHz–2620 MHz for GSM1900, LTE2300, 2.4-GHz WLAN, and LTE2500. The effects of element numbers and configurations on the system performance are investigated. More than 10 dB isolations have been achieved by properly designing the antenna elements through the use of the pattern diversity without using decoupling circuits. The envelope correlation coefficients among the elements, the mean effective gains, the efficiencies, and the multiplexing efficiencies of the elements are also discussed.

/pdf/a-study-of-antenna-system-for-high-order-mimo-device-3vwx1f1viy.pdf

A Study of Antenna System for High Order MIMO Device

Many experiments have demonstrated that a substantial performance improvement may be obtained if multiple antennas are properly designed and are used in handheld devices. For example, the battery life, the the data capacity, the gain and the coverage can be significantly enhanced due to the use of multiple antennas. In this presentation, we explore the possibility of using multiple antennas in handheld devices, which cover three frequency bands 1880MHz–1920MHz, 2300MHz–2400MHz, and 2540MHz–2620MHz. It is shown that four to eight small inverted-F antenna elements can be integrated to the handheld devices of standard dimensions to perform MIMO (multi-input multi-output) or beam steering function to boost the capacity or antenna gain respectively. For MIMO applications, the ECC(envelope correlation coefficient) and MEG(mean effective gain) are investigated and are used to evalutate the performance the MIMO systems with different antenna element designs and arrangements. For beam-steering application, the distribution of excitations for the antenna arrays are determined by optimizing the power transmission coefficient between the antenna array and a testing antenna placed in the desired direction in which radiation must be reinforced. The optimization process yields an eigenvalue equation, which gives the optimized distribution of excitations for the antenna arrays in the specified direcition. The optimized distribution may be realized by various feeding techniques to achieve beam steering in either azimuth plane or elevation plane. A number of examples are expouned to illustrate the design procedure. Various prototypes of antenna arrays are developed, simulated and verified by measurements, to demonstrate the effectiveness of the multiple antenna designs for handheld devices.

Jun Wang

Papers

Printed eight-element MIMO system for compact and thin 5G mobile handest

A Study of Antenna System for High Order MIMO Device

A Study on multiple antenna systems for handheld devices