scholarly journals A Low-Profile and High-isolated MIMO Antenna for 5G Mobile Terminal

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 360 ◽  
Author(s):  
Rongqiang Li ◽  
Zixu Mo ◽  
Haoran Sun ◽  
Xiaofeng Sun ◽  
Guohong Du

An eight-element multiple-input multiple-output (MIMO) frame antenna array in the 3.5 GHz band (3400–3600 MHz) for 5G mobile terminal systems was presented. By using the adjacent grounding and electromagnetic coupling feeding technology, the loop antenna element could generate two resonant frequencies, thus effectively expanding its bandwidth. By adopting double-sided parallel strip line (DSPSL) technology, the electromagnetic coupling inside the loop antenna could be adjusted, and the size of the loop antenna could be effectively reduced so that the MIMO antenna array could obtain a low-profile structure. The total size of the MIMO array was 150 mm × 75 mm × 5.3 mm. Without additional isolation measures, the measured −6 dB impedance bandwidth (BW) was 3400–3660 MHz, and the minimum isolation between antenna elements was better than −20 dB. The proposed antenna was expected to be applied to 5G mobile terminals based on its low-profile, high-isolated characteristics, and good MIMO performance.

2017 ◽  
Vol 9 (8) ◽  
pp. 1741-1748 ◽  
Author(s):  
Mahdi Jalali ◽  
Mohammad Naser-Moghadasi ◽  
Ramezan Ali Sadeghzadeh

Wide-band circularly polarized multi-input multi-output (MIMO) antenna array with a 2 × 4 feed network was proposed for C-band application. Different unique techniques were utilized in the proposed array to enhance the antenna characteristics, such as gain, 3 dB axial ratio bandwidth (ARBW), impedance tuning, and ruinous mutual coupling effects. A miniaturized dual-feed Tai chi-shaped antenna element with a pair of feeding points and a pair of eyebrow-shaped strips was presented for enhancing circular polarization (CP) purity and impedance matching. For a better improvement of CP features, a 2*4 MIMO sequentially rotated (MIMO-SR) feed network was used to achieve broader 3 dB ARBW. Besides, the MIMO feature of the feed network could control the left- and right-handed CP, respectively. Ultimately, specific forms of slot and slit structures were applied onto the top layer of MIMO feed network that provided a high isolation between the radiating elements and array network. Furthermore, the diversity gain (DG) was studied. The extracted measured results illustrated an impedance bandwidth of 3.5–8.2 GHz at port 1 and 3.5–8.3 GHz at port 2 for VWSR < 2 and 3 dB ARBW of 4.6–7.6 GHz at port 1 and 4.6–7.5 GHz at port 2. The peak gain of 9.9 dBi was at 6 GHz.


Author(s):  
Ashraf Tahat ◽  
Bandar Ersan ◽  
Laith Al-Muhesen ◽  
Zaid Shakhshir ◽  
Talal A.Edwan

This paper presents the design of a compact 2´ x 2 microstrip antenna array of size 11.9 ´15.3 mm2 operating at the mm-Wave of 38 GHz. We achieved a high gain of 14.58 dB, a return loss of -17.7 dB, and a wide impedance bandwidth of 500 MHz. This antenna is duplicated twelve times around an angle of 30° forming a low-profile dodecagon. Each sector can cover a beam of 58° to obtain 12 beams covering the 360 degrees. When compared with implemented antenna designs in the literature that target similar features of com-pact size and low-profile at the desired 5G frequency of 38 GHz, our design had a noticeable reduction in size with an increased gain. Our designed antenna is suited for MIMO beamforming, or switched beam technology applications in mobile wireless systems that include miniaturized base stations or moving network systems, such as mobile hotspots or vehicular networks and related elements .


Author(s):  
Hussain Al-Rizzo ◽  
Ayman A. Isaac ◽  
Sulaiman Z. Tariq ◽  
Samer Yahya

This chapter introduces a novel design concept to reduce mutual coupling among closely-spaced antenna elements of a MIMO array. This design concept significantly reduces the complexity of traditional/existing design approaches such as metamaterials, defected ground plane structures, soft electromagnetic surfaces, parasitic elements, matching and decoupling networks using a simple, yet a novel design alternative. The approach is based on a planar single decoupling element, consisting of a rectangular metallic ring resonator printed on one face of an ungrounded substrate. The decoupling structure surrounds a two-element vertical monopole antenna array fed by a coplanar waveguide structure. The design is shown both by simulations and measurements to reduce the mutual coupling by at least 20 dB, maintain the impedance bandwidth over which S11, is less than −10 dB, and reduce the envelope correlation coefficient to below 0.001. The boresight of the far-field radiation patterns of the two vertical monopole wire antennas operating at 2.4 GHz and separated by 8 mm (λo/16), where λo is the free-space wavelength at 2.45 GHz, is shown to be orthogonal and inclined by 45° with respect to the horizontal (azimuthal) plane while maintaining the shape of the isolated single antenna element.


2021 ◽  
Vol 11 (5) ◽  
pp. 2382
Author(s):  
Rongguo Song ◽  
Xiaoxiao Chen ◽  
Shaoqiu Jiang ◽  
Zelong Hu ◽  
Tianye Liu ◽  
...  

With the development of 5G, Internet of Things, and smart home technologies, miniaturized and compact multi-antenna systems and multiple-input multiple-output (MIMO) antenna arrays have attracted increasing attention. Reducing the coupling between antenna elements is essential to improving the performance of such MIMO antenna system. In this work, we proposed a graphene-assembled, as an alternative material rather than metal, film-based MIMO antenna array with high isolation for 5G application. The isolation of the antenna element is improved by a graphene assembly film (GAF) frequency selective surface and isolation strip. It is shown that the GAF antenna element operated at 3.5 GHz has the realized gain of 2.87 dBi. The addition of the decoupling structure improves the isolation of the MIMO antenna array to more than 10 dB and corrects the antenna radiation pattern and operating frequency. The isolation between antenna elements with an interval of 0.4λ is above 25 dB. All experimental results show that the GAF antenna and decoupling structure are efficient devices for 5G mobile communication.


Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 778
Author(s):  
Iftikhar Ahmad ◽  
Houjun Sun ◽  
Umair Rafique ◽  
Zhang Yi

This paper presents a design of a triangular slot-loaded planar rectangular antenna array for wideband millimeter-wave (mm-wave) 5G communication systems. The proposed array realizes an overall size of 35.5 × 14.85 mm2. To excite the array elements, a four-way broadband corporate feeding network was designed and analyzed. The proposed array offered a measured impedance bandwidth in two different frequency ranges, i.e., from 23 to 24.6 GHz and from 26 to 45 GHz. The single-antenna element of the array consists of a rectangular patch radiator with a triangular slot. The partial ground plane was used at the bottom side of the substrate to obtain a wide impedance bandwidth. The peak gain in the proposed array is ≈12 dBi with a radiation efficiency of >90%. Furthermore, the array gives a half-power beamwidth (HPBW) of as low as 12.5°. The proposed array has been fabricated and measured, and it has been observed that the measured results are in agreement with the simulated data.


Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 651-655 ◽  
Author(s):  
Yilin Liu ◽  
Kama Huang

Abstract A novel design of a coplanar waveguide (CPW) feed antenna array with circular polarization (CP) and a high front-to-back ratio is described. The proposed CP array is achieved by using a compact CPW–slotline transition network etched in the ground plane. The measured results show that this kind of feeding method can improve the impedance bandwidth, as well as the axial ratio bandwidth of the CP antenna array and provide adequate gain. The proposed array can achieve a 6.08% impedance bandwidth and a 4.10% CP bandwidth. Details of the antenna design and experimental results are presented and discussed.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Zixian Yang ◽  
Hongchun Yang ◽  
Haijuan Cui

A compact printed MIMO antenna for mobile terminals is presented. With two planar antenna elements, the −6 dB impedance bandwidth of 2.32 GHz (1.48–3.8 GHz) is obtained, which covers GSM 1800/1900, UMTS, WLAN, Wimax, S-band, and most of LTE bands. Each antenna element with a small occupation of 15 × 20 mm2consists of a driven strip and a shorted strip. Two inverted C-shaped ground branches are introduced between two elements to improve the isolation. The simulated results are studied and the measured results show that high isolation of more than 18 dB at the entire operating band is achieved. Meanwhile, the impedance performance is also improved by adding the branches. Furthermore, the measured radiation performances and envelope correlation coefficient also demonstrate that the proposed antenna could be a good candidate for mobile terminals.


2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Guang Sun ◽  
Ge Gao ◽  
Tingting Liu ◽  
Yi Liu ◽  
Hu Yang

In this paper, a wideband slot antenna element and its array with stereoscopic differentially fed structures are proposed for the radar system. Firstly, a series of slots and a stereoscopic differentially fed structure are designed for the antenna element, which makes it possess a wide bandwidth, stable radiation characteristics, and rather high gain. Moreover, the stereoscopic feeding structure can firmly support the antenna’s radiation structure and reduce the influence of feeding connectors on radiating performance. Secondly, a 4 × 4 array is designed using the proposed antenna element. And a hierarchical feeding network is designed for the array on the basis of the stereoscopic differentially fed structure. For validation, the antenna element and 4 × 4 array are both fabricated and measured: (1) the measured −10 dB impedance bandwidth of the antenna element is 62% (6.8–12.9 GHz) and the gain within the entire band is 5–9.7 dBi and (2) the measured −10 dB impedance bandwidth of the array is approximately 50% (7 to 12 GHz) with its gain being 14–19.75 dBi within the entire band. Notably, measured results agree well with simulations and show great advantages over other similar antennas on bandwidth and gain.


Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3062
Author(s):  
Jalal Khan ◽  
Sadiq Ullah ◽  
Farooq A. Tahir ◽  
Faisel Tubbal ◽  
Raad Raad

This paper presents a novel antenna with its array and MIMO configuration for the 5G sub-6 GHz applications. The proposed antenna element operates at the central frequency of 5.57 GHz dedicated for Sub-6 GHz 5G communication applications. The antenna element holds a circular-shaped radiating portion with an inner-circular slot, plus a rectangular slot at its right edge to make the proposed design resonate at the desired frequency band. The RT5880 substrate is used with a thickness of 0.787 mm, and the low-loss tangent of 0.0009. To achieve a desired gain of 12 dB, a four-element array configuration is adopted, which improved a bore side gain to 12.4 dB from 6.66 dB. Then, the two-port configuration is adopted such that the isolation achieved between them is more than −30 dB. The total efficiency of the proposed antenna array is observed to be more than 80% within the operating bandwidth. Moreover, the Specific Absorption Rate (SAR) analysis is also presented for the proposed MIMO configuration, obeying the standard value (i.e., <2 W/kg for any 10 g of tissue). The measured results are in good agreement with the simulated results. All the simulations of the proposed design are performed in the CST MWS software.


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