Experimental investigation on the effect of user's hand proximity on a compact ultrawideband MIMO antenna array

Zhekov, Stanislav Stefanov; Tatomirescu, Alexandru; Foroozanfard, Ehsan; Pedersen, Gert Frølund

doi:10.1049/iet-map.2016.0054

Cited by 17 publications

(14 citation statements)

References 24 publications

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“…However, the performance of MIMO antennas on user mobile terminal can potentially be restricted when the device is held in different data or talk modes [7]. Using the device in the vicinity of user body causes variation in the radiation pattern of AEs, increases radiated power absorption as well as changes their bandwidth and resonant frequency [8]. Studying the effect of user body on the MIMO antenna of the mobile terminal and proposing some techniques to mitigate this effect is an important research direction in the field of MIMO antenna design for mobile terminals, for example [9]- [14].…”

Section: Introductionmentioning

confidence: 99%

“…All MIMO antennas are designed to operate throughout the potential 5G frequency band from 5 to 6 GHz, which consists of LTE band 46 ranging from 5150 MHz to 5925 MHz. Although this band is still unlicensed, many MIMO antennas for mobile terminal operating on this band have been proposed and evaluated, for example [8], [26], [28]- [32]. The PIFA topology chosen as the subject of this investigation due to its wide application in mobile terminals.…”

Section: Introductionmentioning

confidence: 99%

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Performance Study of a MIMO Mobile Terminal With Upto 18 Elements Operating in the Sub-6 GHz 5G Band With User Hand

et al. 2020

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This paper investigates the performance variation when a different number of antenna elements (AEs) is integrated onto a single MIMO mobile terminal, both in free space and when held in a user hand in data mode. Starting with a minimum of two AEs, this investigation assessed the performance of the MIMO terminal with every additional two AEs (up to 18 AEs) in terms of envelope correlation coefficient (ECC), efficiency, multiplexing efficiency, capacity and maximal ratio combining (MRC). The integrated MIMO antennas are identical and operate between 5 and 6 GHz for 5G applications. Results indicated that ECC increased with the number of AEs. However, ECC remains less than 0.32 for the case of 18 AEs in both free space and with a user hand. Meanwhile, the free space efficiency of about 90 % for the two AEs is observed to decrease with the increasing number of AEs to about 50 % with 18 AEs. However, the efficiency of elements changes with user hand depending on the level of interaction between each element and the hand. Direct blockage of AEs by the hand resulted in efficiencies of as low as 5 %, while at the same time, other AEs retained an efficiency of up to 75 %. At the center frequency of 5.5 GHz, the free space capacity is 11.1, 49.5 and 83.2 bit/s/Hz with two, ten and 18 AEs, respectively. However, the use of the mobile terminal in the proximity of the user hand degraded these levels by 11 % (two AEs), 35 % (10 AEs) and 31 % (18 AEs). Finally, multiplexing efficiency showed that capacity degradation is caused mainly by the degradation of AEs efficiency, whereas the impact of low correlation between AEs is found to be an insignificant factor. In addition to the capacity analysis, gain and diversity gain of the maximal ratio combining technique was also investigated. INDEX TERMS Ergodic capacity, 5G MIMO antenna, mobile terminal, multiplexing efficiency, user effect, maximal ratio combining.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance Study of a MIMO Mobile Terminal With Upto 18 Elements Operating in the Sub-6 GHz 5G Band With User Hand

et al. 2020

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“…One of the main key design components to realize high data rates in modern wireless communication systems is MIMO antennas [1,2]. These MIMO antennas should have low correlation between their ports and high total efficiency of ports [3]. Performance evaluation of MIMO antennas is an essential step to design an efficient MIMO link.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, user's hand and body reduce the amount of radiated power due to absorption by the body tissue. They can also shift the resonant frequency and operating bandwidth of the antenna [3,5,6]. In [7] a review is provided about the effect of user's body on mobile terminal antennas and discusses several proposed techniques in the literature to mitigate this effect.…”

Section: Introductionmentioning

confidence: 99%

Envelope Correlation Coefficient of a Two-Port Mimo Terminal Antenna Under Uniform and Gaussian Angular Power Spectrum With User's Hand Effect

Elshirkasi¹,

Al‐Hadi²,

Mansor³

et al. 2019

PIER C

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This paper studies the effects of incident wave angular power spectrum (APS) distribution and user hand effect on the envelope correlation coefficient (ECC) of a two-port MIMO antenna operating in the sub 6 GHz LTE-U frequency band. APS of uniform and Gaussian distributions are used with different Gaussian angular spread (AS) values, i.e., 10 • , 30 • , 50 • , and 70 •. A prototype was fabricated, and three-dimensional radiation patterns of the antenna elements were measured in an anechoic chamber from 4 to 6 GHz in both cases of free space and when the prototype is held in data mode using a hand phantom. An algorithm to calculate ECC from the complex data of far field radiation pattern with different APS distributions is explained in detail. Results show that user hand presence increases ECC between ports compared with free space, whose increase is more obvious under Gaussian APS. ECC values under uniform APS is practically zero over the entire frequency range except at frequencies close to 6 GHz, where the highest ECC values are 0.13 and 0.16 in free space and with user hand, respectively. However, Gaussian APS with different ASs shows a significant impact of the ECC. With narrow AS of 10 • , ECC at some incident directions can be as high as 0.84 (in free space) and 0.92 (with user hand), and the mean ECC values under this AS are 0.25 (in free space) and 0.37 (with user hand). ECC values keep decreasing as AS gets wider, with the maximum ECC at AS = 70 • observed to be 0.23 and 0.34 in free space and with user hand, respectively, whereas the mean ECC values are close to uniform APS. Statistical distribution of the ECC showed good agreement with exponential distribution, with a better agreement between measured ECC and exponential distribution observed in free space with wider AS.

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“…Moreover, the performance of MIMO antennas of mobile terminal is limited by the effect of user's body (hands and head) when the device is used in data or talk modes [8]. The body tissues absorb radiated power and change the radiation pattern of antenna elements, besides potentially shifting their resonant frequencies and bandwidths [9]. The effects of user body on MIMO antennas have been investigated for different MIMO designs, frequency bands, and evaluation metrics, for example [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

A Study of Antenna Elements Configuration and User's Hand Effects on a Four-Element Dual-Band Sub-6 GHZ Mimo Antenna

Elshirkasi¹,

Al‐Hadi²,

Mansor³

et al. 2019

PIER C

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This paper evaluates the performance of different configurations of MIMO antenna operating in the 5G band with the effect of user's hand in data mode and suggests an optimized configuration to mitigate hand effects. A dual-band four-element MIMO antenna is used. All antenna elements (AEs) are identical planar inverted-F antenna (PIFAs) with a lower frequency band (LB) from 3.3 to 3.8 GHz and an upper frequency band (UB) from 5.2 to 6 GHz. In addition, four different configurations to place the AEs on the chassis are selected including worst and optimized configurations as well two intermediate cases. Results show that similar values of ECC are produced for both cases without and with user hand. These values are less than 0.20 on most frequency range, except the worst case configuration which has some high ECC values close to unity. Unlike ECC, TE is severely affected by user's hand as well as by the different configuration. TE of each AE under hand effect is degraded differently according to the thickness of hand tissue that covers it. TE in the optimized configuration without user's hand ranges between 50 and 95% in both frequency bands. However, this range deteriorates when user's hand effect is considered, between 40% and 15% in LB, and from 35% to 41% in the UB. Multiplexing efficiency analysis reveals that MIMO performance is mainly determined by TE, and the impact of the low ECC is insignificant. This indicates that improving the performance depends on improving the TE of AEs and optimizing their positions on the chassis to reduce interaction with user's hand. Moreover, the loss in ergodic capacity due to user's hand compared with free space is increased from 5 to 40% in the LB, and it is more stable in the UB and ranging between 12 and 17%.

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Experimental investigation on the effect of user's hand proximity on a compact ultrawideband MIMO antenna array

Cited by 17 publications

References 24 publications

Performance Study of a MIMO Mobile Terminal With Upto 18 Elements Operating in the Sub-6 GHz 5G Band With User Hand

Performance Study of a MIMO Mobile Terminal With Upto 18 Elements Operating in the Sub-6 GHz 5G Band With User Hand

Envelope Correlation Coefficient of a Two-Port Mimo Terminal Antenna Under Uniform and Gaussian Angular Power Spectrum With User's Hand Effect

A Study of Antenna Elements Configuration and User's Hand Effects on a Four-Element Dual-Band Sub-6 GHZ Mimo Antenna

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