scholarly journals Design of a Compact UWB MIMO Antenna without Decoupling Structure

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanjie Wu ◽  
Kang Ding ◽  
Bing Zhang ◽  
Jianfeng Li ◽  
Duolong Wu ◽  
...  

A compact high isolation ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna is designed. The proposed MIMO antenna consists of a rectangular monopole antenna and a slot antenna fed by two microstrip lines, respectively. To improve the impedance matching, a circular coupling structure is designed to feed the tapered slot antenna. The parasitic resonance introduced by the ground stub helps to extend the impedance bandwidth of monopole antenna at the upper UWB band. Commonly used complex decoupling or coupling structures are eliminated that endow the proposed antenna minimized foot print, which is preferred in mobile handset. Although without decoupling structure, high isolation is obtained between two antenna elements. Simulation and measurement verify the antenna’s desirable performance, showing a broad impedance bandwidth of 3.1–10.6 GHz with |S11| < −10 dB and |S21| < −20 dB over 3.4–10.6 GHz, and |S21| < −18 dB from 3.1–3.4 GHz.

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yanjie Wu ◽  
Yunliang Long

This paper presents a long-term evolution (LTE) 700 MHz band multiple-input-multiple-output (MIMO) antenna, and high isolation between the two symmetrical antenna elements is obtained without introducing extra decoupling structure. Each antenna element is a combination antenna of PIFA and a meander monopole antenna. The end of the PIFA and the meander monopole antenna are, respectively, overlapped with the 50 Ω microstrip feed line, the two overlapping areas produce additional capacitance which can be considered decoupling structures to enhance the isolation for the MIMO antenna, as well as the impedance matching of the antenna elements. The MIMO antenna is etched on FR4 PCB board with dimensions of 71 × 40 × 1.6 mm3; the edge-to-edge separation of the two antenna elements is only nearly 0.037 λat 700 MHz. Both simulation and measurement results are used to confirm the MIMO antenna performance; the operating bandwidth is 698–750 MHz withS11≤−6 dB andS21≤−23 dB.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
A. Mchbal ◽  
N. Amar Touhami ◽  
H. Elftouh ◽  
A. Dkiouak

A compact ultra-wideband (UWB) multiple input-multiple output (MIMO) antenna with high isolation is designed for UWB applications. The proposed MIMO antenna consists of two identical monopole antenna elements. To enhance the impedance matching, three slots are formed on the ground plane. The arc structure as well as the semicircle with an open-end slot is employed on the radiating elements the fact which helps to extend the impedance bandwidth of the monopole antenna from 3.1 up to 10.6 GHz, which corresponds to the UWB band. A ground branch decoupling structure is introduced between the two elements to reduce the mutual coupling. Simulation and measurement results show a bandwidth range from 3.1 to 11.12 GHz with |S11_|<−15 dB, |S21_|<−20 dB, and ECC < 0.002.


Frequenz ◽  
2017 ◽  
Vol 71 (5-6) ◽  
Author(s):  
Lingsheng Yang ◽  
Ming Ji ◽  
Biyu Cheng ◽  
Bo Ni

AbstractIn this letter, an eight-element Multiple-input multiple-output (MIMO) antenna system for LTE mobile handset applications is proposed. The antenna array consists of eight 3D inverted F-shaped antennas (3D-IFA), and the measured –10 dB impedance bandwidth is 3.2–3.9 GHz which can cover the LTE bands 42 and 43 (3.4–3.8 GHz). By controlling the rotation of the antenna elements, no less than 10 dB isolation between antenna elements can be obtained. After using the specially designed meandered slots on the ground as decoupling structures, the measured isolation can be further improved to higher than 13 dB between the antenna elements at the whole operating band.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Qinghao Zeng ◽  
Yuan Yao ◽  
Shaohua Liu ◽  
Junsheng Yu ◽  
Peng Xie ◽  
...  

A compact printed multiple-input multiple-output (MIMO) antenna for tetraband (GSM900/1800/1900/UMTS) mobile handset application is presented. The proposed MIMO antenna, which consists of two coupled-fed loop antennas with symmetrical configuration, was printed on a 120 * 60 * 0.8 mm3Fr-4 substrate of relative permittivity of 4.4, loss tangent 0.02. Each element antenna requires only a small area of 22.5 * 25 mm2on the circuit board. The edge-to-edge spacing between the two elements is only0.03λ0of 920 MHz. A slot and a dual-inverted-L-shaped ground branch were added in the ground plane to decrease the mature coupling between the antenna elements. The measured isolation of the proposed antenna is better than 15 dB among the four operating frequency bands. The simulated 3D radiation patterns at 900 MHz and 1900 MHz of both antenna elements show that two loop antennas in general cover complementary space regions with good diversity performance. Detailed antenna impedance matching performance comparisons were done to evaluate the benefit of using different decoupling technology. The envelop correlation coefficient is calculated to represent the diversity performance of the MIMO antenna.


Author(s):  
Pavithra S ◽  
AmeeliaRoseline A

In MIMO(multiple input multiple output) system, antenna performance are degraded by mutual coupling hence to overcome this we go for circular polarization. In this paper we use planar, circularly polarized MIMO patch with three grounded stubs, F-shaped mirrored structure to achieve same time isolation &matching with offset feeding between two patches for circularly polarization.The elements of antenna are closely packed with 0.06λ0 of edge to edge distance at 2.5 GHZ frequency. The proposed antenna will results the impedance matching S11 < -10 dB and high isolation of S12 < -20 dB.


Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 432
Author(s):  
Muhammad Irshad Khan ◽  
Muhammad Irfan Khattak ◽  
Saeed Ur Rahman ◽  
Abdul Baseer Qazi ◽  
Ahmad Abdeltawab Telba ◽  
...  

This paper proposes a compact, semi-circular shaped multiple input multiple output (MIMO) antenna design with high isolation and enhanced bandwidth for ultrawide band (UWB) applications. A decoupling stub is used for high isolation reaching up to −55 dB over the entire bandwidth. The proposed antenna is used for UWB as well as super wide band (SWB) applications. The overall size of the proposed antenna is 18 × 36 × 1.6 mm3. The | S 11 | and voltage standing wave ratio (VSWR) of the proposed antenna are less than −10 dB and 2, respectively, in the range of 3–40 GHz. The total impedance bandwidth of the proposed design is 37 GHz. The VSWR, | S 11 | , | S 22 | , | S 21 | , | S 12 | , gain, envelope correlation coefficient (ECC), radiation pattern, and various other characteristic parameters are discussed in detail. The proposed antenna is optimized and simulated in a computer simulation technology (CST) studio, and printed on a FR4 substrate.


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2688
Author(s):  
Wenfei Yin ◽  
Shaoxiang Chen ◽  
Junjie Chang ◽  
Chunhua Li ◽  
Salam K. Khamas

In the paper, an extremely compact multiple-input-multiple-output (MIMO) antenna is proposed for portable wireless ultrawideband (UWB) applications. The proposed prototype consists of four monopole antenna elements, which are placed perpendicularly to achieve polarization diversity. In addition, the mutual coupling between antenna elements is suppressed by designing the gap between the radiation element and the ground plane. Moreover, a matching stub has been connected to the feedline to ensure impedance matching in high frequency. Both simulated and measured results indicate that the proposed antenna has a bandwidth of 3–20 GHz, with a high isolation better than 17 dB. In addition, the designed MIMO antenna offers excellent radiation characteristics and stable gain over the whole working band. The envelope correlation coefficient (ECC) is less than 0.1, which shows that the antenna can meet the polarization diversity characteristics well.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Abubaker Ahmed Elobied ◽  
Xue-Xia Yang ◽  
Ningjie Xie ◽  
Steven Gao

This paper presents a close-spaced dual-band 2 × 2 multiple-input multiple-output (MIMO) antenna with high isolation based on half-mode substrate integrated waveguide (HMSIW). The dual-band operation of the antenna element is achieved by loading a rectangular patch outside the radiating aperture of an HMSIW cavity. The HMSIW cavity is excited by a coaxial probe, whereas the rectangular patch is energized through proximity coupling by the radiating aperture of HMSIW. The antenna elements can be closely placed using the rotation and orthogonal arrangement for a 2 × 2 array. Small neutralization lines at the center of the MIMO antenna can increase the isolation among its elements by around 10 dB in the lower band and 5 dB in the higher band. A prototype of the MIMO antenna is fabricated and its performance is measured. The measured results show that the resonant frequencies are centered at 4.43 and 5.39 GHz with bandwidths of 110 and 80 MHz and peak gains of 6 and 6.4 dBi, respectively. The minimum isolation in both bands is greater than 35 dB. The envelope correlation coefficient is lower than 0.005 within two operating bands.


2016 ◽  
Vol 9 (3) ◽  
pp. 573-580 ◽  
Author(s):  
Garima Srivastava ◽  
B. K. Kanuijia ◽  
Rajeev Paulus

A compact printed 2 × 2 ultrawideband (UWB) multiple input multiple output (MIMO) antenna with a single circular patch as a common radiator for both the antenna elements is presented in this paper. A single circular patch is excited by two tapered CPW feeds for dual polarization. To improve the isolation between two ports, a rectangular slot of dimension L1 × W1 is created in the radiator. The UWB MIMO antenna has impedance bandwidth of 3–12 GHz with a isolation better than 17 dB between the two ports. The envelope correlation coefficient and the capacity loss are evaluated to ensure the good diversity performance of UWB MIMO antenna. The antenna has a compact size of 45 × 45 mm2 and is fabricated on low cost FR4 substrate and measured using Agilent VNA. The simulated and measured results show that the proposed UWB antenna is good candidate for UWB MIMO applications.


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