scholarly journals A Novel 2.4-GHz Low-Profile Smart MIMO Antenna with Reconfigurable Frequency-Selective Reflectors

2020 ◽  
Vol 9 (2) ◽  
pp. 42-51
Author(s):  
C.-H. Tsai ◽  
J.-S. Sun ◽  
S.-J. Chung ◽  
J.-H. Tarng

In this paper, a new low-profile smart multiple-input multiple-output (MIMO) antenna system is presented for WiFi IEEE 802.11a/b/g/n/ac/ax applications. The proposed compact 2.4-GHz antenna system employs two beam-switching antenna cells for MIMO operation. Each antenna cell is composed of four reconfigurable frequency-selective reflectors (RFSRs) and a one-to-four switching feeding network. The RFSRs are constructed using a one-wavelength metal loop resonator, which functions as a radiating antenna or a wave reflector to reflect beams along a specific direction, as controlled by the switching network. The feeding switching network utilizes PIN diodes to adjust the phase and impedance required for changing the operational status of each RFSR. The overall dimensions of the antenna system, including the metallic ground, are 120 mm ´ 120 mm ´ 9.5 mm. Moreover, the measured operational bandwidth of the 2.4-GHz antenna is approximately 100 MHz, and the radiation efficiency of each directed beam is 40%–70%.

2013 ◽  
Vol 64 (3) ◽  
Author(s):  
Nassrin Ibrahim Mohamed ◽  
Tharek Abd. Rahman ◽  
Mursyidul Idzam Sabran

This paper presents a Low-profile slot meander patch antennas. The antenna is a multiple communication bands for handheld devices and implements multiple-input–multiple-output (MIMO) technique. The proposed model covers LTE band-11 1.5 GHz Lower (1427.9 - 1452.9, 1475.9 - 1500.9), LTE band-2 PCS 1900 (1930 -1990, 1850 -1910), LTE band-7 2.6 GHz (2620-2690, 2500- 2570), and LTE band-22 3.5 GHz (3510-3590, 3410-3490) with dB matching criterion (VSWR 3:1). An isolation less than -15 dB has been obtained between two typical slot meander patch antennas. The isolation is achieved as a result of using CPW feeding mechanism and inserted CLL network isolator. This dual-feed (2-elements) planar antenna is fabricated and measured. The result of this small size structured MIMO antenna system shows a good radiation characteristics and small mutual coupling which is promising for MIMO applications in compact portable devices.


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.


2019 ◽  
Vol 8 (1) ◽  
pp. 75-81
Author(s):  
N. Al Shalaby ◽  
S. G. El-Sherbiny

In this paper, A multiple input Multiple Output (MIMO) antenna using two Square Dielectric Resonators (SDRs) is introduced. The mutual coupling between the two SDRAs is reduced using two different methods; the first method is based on splitting a spiral slot in the ground plane, then filling the slot with dielectric material, "E.=2.2". The second method is based on inserting a copper parasitic element, having the same shape of the splitted Spiral, between the two SDRAs.  The effect of replacing the copper parasitic element with Carbon nanotubes (CNTs) parasitic element "SOC12 doped long-MWCNT BP" is also studied. The antenna system is designed to operate at 6 GHz. The analysis and simulations are carried out using finite element method (FEM). The defected ground plane method gives a maximum isolation of l8dB at element spacing of 30mm (0.6λo), whereas the parasitic element method gives a maximum isolation of 42.5dB at the same element spacing.


Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1083
Author(s):  
Saifur Rahman ◽  
Xin-cheng Ren ◽  
Ahsan Altaf ◽  
Muhammad Irfan ◽  
Mujeeb Abdullah ◽  
...  

In this work, a new Multiple Input Multiple Output (MIMO) antenna system with a novel shape inspired by nature is proposed for Fifth-Generation (5G) communication systems. The antenna is designed on a Rogers 5880. The dielectric constant of the substrate is 2.2, and the loss tangent is assumed to be 0.0009. The gain of the system for the desired bandwidth is nearly 8 dB. The simulated and the measured efficiency of the proposed system is 95% and 80%, respectively. To demonstrate the capability of the system as a potential candidate for future 5G communication devices, MIMO key performance parameters such as the Envelope Correlation Coefficient (ECC) and Diversity Gain (DG) are computed. It is found that the proposed system has low ECC, constant DG, and high efficiency for the desired bandwidth.


Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1321
Author(s):  
Amjad Iqbal ◽  
Ahsan Altaf ◽  
Mujeeb Abdullah ◽  
Mohammad Alibakhshikenari ◽  
Ernesto Limiti ◽  
...  

This paper presents an isolation enhancement of two closely packed multiple-input multiple-output (MIMO) antenna system using a modified U-shaped resonator. The modified U-shaped resonator is placed between two closely packed radiating elements resonating at 5.4 GHz with an edge to edge separation distance of 5.82 mm (λ∘/10). Through careful adjustment of parametric modelling, the isolation level of −23 dB among the densely packed elements is achieved. The coupling behaviour of the MIMO elements is analysed by accurately designing the equivalent circuit model in each step. The antenna performance is realized in the presence and absence of decoupling structure, and the results shows negligible effects on the antenna performance apart from mutual coupling. The simple assembly of the proposed modified U-shaped isolating structure makes it useful for several linked applications. The proposed decoupling structure is compact in nature, suppress the undesirable coupling generated by surface wave and nearby fields, and is easy to fabricate.


Author(s):  
Nur Zafirah Bt Muhammad Zubir Et.al

A wideband multiple-input-multiple-output (MIMO) antenna system with common elements suitable for SCADA wireless communication backhaul application which is operating frequency of 0.85-2.6GHz that can cover global system for mobile communication (GSM) 900MHz and 1.8GHz, The Universal Mobile Telecommunication System (UMTS) 2GHz, Wi-Fi (2.4GHz) and Long Term Evolution (LTE) 2.6GHz is proposed. The proposed MIMO antenna system consists of four microstrip feedline with common radiating element and a frame shaped ground plane. A single port antenna also was designed and presented in this paper to show the process to design wideband MIMO antenna structure. The radiator of the MIMO antenna system is designed as the shape of modified rectangle with straight line at each corner to enhance the bandwidth frequency. To improve the isolation between ports, the ground plane is modified by inserting four L-slots in each corner to reduce mutual coupling. For an antenna efficiency of more than 60%, the simulated reflection coefficients are below -10dB for all ports at expected frequency. Simulated isolation is achieved greater than -10dB by using a modified ground plane. Also, a low envelope correlation coefficient (ECC) less than 0.1 and polarization diversity gain of about 10dB with the orthogonal mode of linear polarization and omnidirectional pattern during the analysis of the radiation characteristic are achieved. Therefore, the proposed design can be used for SCADA wireless communication backhaul application.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1559
Author(s):  
Adam R. H. Alhawari ◽  
Tale Saeidi ◽  
Abdulkarem Hussein Mohammed Almawgani ◽  
Ayman Taher Hindi ◽  
Hisham Alghamdi ◽  
...  

A low-profile Multiple Input Multiple Output (MIMO) antenna showing dual polarization, low mutual coupling, and acceptable diversity gain is presented by this paper. The antenna introduces the requirements of fifth generation (5G) and the satellite communications. A horizontally (4.8–31 GHz) and vertically polarized (7.6–37 GHz) modified antipodal Vivaldi antennas are simulated, fabricated, and integrated, and then their characteristics are examined. An ultra-wideband (UWB) at working bandwidths of 3.7–3.85 GHz and 5–40 GHz are achieved. Low mutual coupling of less than −22 dB is achieved after loading the antenna with cross-curves, staircase meander line, and integration of the metamaterial elements. The antennas are designed on a denim textile substrate with = 1.4 and h= 0.5 mm. A conductive textile called ShieldIt is utilized as conductor with conductivity of 1.8 × 104. After optimizing the proposed UWB-MIMO antenna’s characteristics, it is increased to four elements positioned at the four corners of a denim textile substrate to be employed as a UWB-MIMO antenna for handset communications, 5G, Ka and Ku band, and satellite communications (X-band). The proposed eight port UWB-MIMO antenna has a maximum gain of 10.7 dBi, 98% radiation efficiency, less than 0.01 ECC, and acceptable diversity gain. Afterwards, the eight-ports antenna performance is examined on a simulated real voxel hand and chest. Then, it is evaluated and compared on physical hand and chest of body. Evidently, the simulated and measured results show good agreement between them. The proposed UWB-MIMO antenna offers a compact and flexible design, which is suitably wearable for 5G and satellite communications applications.


Author(s):  
Aziz Dkiouak ◽  
Mohssine El Ouahabi ◽  
Alia Zakriti ◽  
Mohsine Khalladi ◽  
Aicha Mchbal

In this paper, a compact dual band multiple-input multiple-output (MIMO) antenna system for WLAN and X-band satellite applications (2.4/9.8 GHz respectively) is proposed. On the top face of the substrate, two antenna elements with a size of 20 × 24 mm2 are placed side by side and fed with matched orthogonal micro-strip lines. The two antenna elements have orthogonal polarization which can reduce the mutual coupling between its ports. The designed antenna system is fabricated and measured to validate the simulation results. The impedance bandwidths are about 370 MHz (2.19 to 2.56 GHz) and 630 MHz (9.44 to 10.07 GHz), while the obtained isolation is greater than 14 dB at the operating bands. Furthermore, the envelope correlation is less than 0.052 and 0.008 at 2.4 and 9.8 GHz, respectively. Hence the diversity gain is higher than 9.98 in the frequency bands of interest.


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7909
Author(s):  
Saminathan Thiruvenkadam ◽  
Eswaran Parthasarathy ◽  
Sandeep Kumar Palaniswamy ◽  
Sachin Kumar ◽  
Lulu Wang

This article presents a quad-band multiple-input-multiple-output (MIMO) antenna for the Internet of Things (IoT) applications. The proposed antenna consists of four quarter-wavelength asymmetrical meandered radiators, microstrip feed lines, and modified ground planes. The antenna elements are arranged in a chiral pattern to improve isolation between them, with two radiators and two ground planes placed on the front side of the substrate and the other two on the back side. The MIMO antenna has an operating bandwidth (S11 ≤ −10 dB) of 1.76–1.84 GHz, 2.37–2.56 GHz, 3.23–3.68 GHz, and 5.34–5.84 GHz, covering GSM, WLAN, WiMAX, and 5G frequency bands. The isolation between the radiating elements is greater than 18 dB in the operating bands. The peak gain of the antenna is 3.6 dBi, and the envelope correlation coefficient (ECC) is less than 0.04. Furthermore, the proposed antenna is validated for IoT-based smart home (SH) applications. The prototype MIMO antenna is integrated with a commercially available ZigBee device, and the measured values are found to be consistent with the expected results. The proposed MIMO antenna could be a good candidate for IoT systems/modules due to its low profile, compact size, lightweight, and easy integration with wireless communication devices.


Frequenz ◽  
2017 ◽  
Vol 71 (11-12) ◽  
Author(s):  
A. Raza ◽  
Muhammad U. Khan ◽  
Farooq A. Tahir

AbstractIn this paper, a two element frequency reconfigurable multiple-input-multiple-output (MIMO) antenna system is presented. The proposed antenna consists of miniaturized patch antenna elements, loaded with varactor diodes to achieve frequency reconfigurability. The antenna has bandwidth of 30 MHz and provides a smooth frequency sweep from 2.12 GHz to 2.4 GHz by varying the reverse bias voltage of varactor diode. The antenna is designed on an FR4 substrate and occupies a space of 50×100 × 0.8 mm


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