Isolation Enhancement between Ports of a Compact Ultra-wideband MIMO Antenna

2021 ◽  
Vol 36 (1) ◽  
pp. 61-66
Author(s):  
Yantao Yu ◽  
Shenshen Mao ◽  
Meng Li ◽  
Danting He

In this paper, a novel compact multiple-input multiple-output (MIMO) antenna with enhanced port isolation is proposed for ultra-wideband (UWB) applications. The UWB MIMO antenna contains two coplanar annular monopoles etched on the front side of the FR-4 substrate. The dielectric substrate has a relative permittivity of 4.4 and a size of 80 mm × 40 mm × 1.6 mm. The irregular ground is printed on the back side of the substrate. In order to enhance the port isolation between the two monopoles, the expanded ground is exploited in the proposed design. In addition, the ground is etched with some slots to achieve good impedance matching. Both the simulated and measured results show that the proposed antenna achieves good impedance matching as well as high port isolation over the entire UWB band. Moreover, the proposed antenna has good spatial diversity characteristics. In summary, the proposed UWB MIMO antenna can be well applied to the ultra-wideband wireless communication system.

2020 ◽  
Vol 9 (3) ◽  
pp. 56-65
Author(s):  
A. Mchbal ◽  
N. Amar Touhami ◽  
H. Elftouh ◽  
A. Dkiouak

A high order multiple input multiple output (MIMO) antenna assembly is designed for Ultra-Wideband (UWB) applications. The antenna configuration is based on a peculiar arrangement of the radiating elements. A defected microstrip structure is also introduced on the feedlines. The use of a novel technique, the so-called ports-shift, is here discussed. In the proposed antenna, a protruded ground branch structure is employed in combination of three parasitic stubs so as to enhance isolation and impedance matching over the UWB frequency band. The results show that the presented antenna exhibits a good impedance matching which is about -10 dB with a high mutual coupling 15 dB, and envelope correlation coefficients (ECC) smaller than 0.15. The antenna also exhibits good diversity gain of about 9.5, and a good efficiency that varied between 56% and 91% and total active reflection coefficient of less than -20 dB. Which makes it a good candidate for UWB applications.


2018 ◽  
Vol 10 (8) ◽  
pp. 948-955 ◽  
Author(s):  
Ling Wu ◽  
Yingqing Xia ◽  
Xia Cao ◽  
Zhengtao Xu

AbstractA simple multiple-input-multiple-output (MIMO) antenna with quad-band-notched characteristics for ultra-wideband (UWB) system is proposed and tested in the article. Based on two similar radiators, the UWB-MIMO system only occupies 22 mm × 28 mm. By etching an inverted L-like meander slot, two inverted L-shaped slots, and adding a C-shaped stub beside the feeding line, four notched bands are realized (3.25–3.6, 5.05–5.48, 5.6–6, and 7.8–8.4 GHz) to suppress interference from WiMAX, lower WLAN, upper WLAN, and uplink of X-band satellite communication system. With a T-like stub extruding from the ground plane, port isolation is effectively improved. The results show that the antenna covers 3.1–10.6 GHz UWB frequency band except four rejected bands and has high isolation of better than −20 dB over most of the frequency band. Moreover, envelope correlation coefficient and good radiation patterns also prove that the introduced antenna is suitable for UWB applications.


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.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Minghuan Wang ◽  
Jingchang Nan ◽  
Jing Liu

A miniaturized ultra-wideband multiple-input multiple-output (UWB MIMO) two-port antenna with high isolation based on FR4 is designed in this article. The size of the antenna is only 18 × 28 × 1.6 mm3. The MIMO antenna consists of two identical antenna elements symmetrically placed on the same dielectric substrate in opposite directions. By loading three crossed X-shaped stubs between two unconnected ground planes, high isolation and good impedance matching are achieved. The working frequency band measured by this UWB MIMO antenna is 1.9–14 GHz, and the isolation is kept above 20.2 dB in the whole analysis frequency band. Good radiation characteristics as well as envelope correlation coefficient (ECC, <0.09), mean effective gain (MEG), and channel capacity loss (CCL) in the passband meet the requirements of the application, which can be applied to the UWB wireless communication system. To verify the applicability of the proposed method for enhancing the isolation between antenna elements, the two-port antenna structure was extended to a four-port antenna structure. In the case of loading the X-shaped stubs to connect to the ground plane, the isolation of the antenna is maintained above 15.5 dB within 1.7–14 GHz.


2021 ◽  
pp. 1-7
Author(s):  
Ahmed Shaker ◽  
◽  
Ayman Haggag

A compact ultra-wideband (UWB) Multiple-Input-Multiple-Output (MIMO) antenna with a notched band is presented. The proposed design consists of four unipolar UWB radiators, and these monopole radiators are placed perpendicular to each other to exploit polarization diversity, where the four-element ultra-wideband (UWB) Multiple-Input-Multiple-Output (MIMO) antenna is presented. The total size of the antenna is 60x60 mm2. The operating frequency of the antenna is 3.1–11 GHz with a return loss of less than 10 dB, except at the notched band of 4.9– 5.9 GHz. This antenna consists of an isosceles trapezoidal plate with a circular notch cut and two transitional steps as well as a partial ground plane. For UWB bandwidth enhancement techniques: use of a partial ground plane, and modify the gap between the radioactive element and ground plane technique, using steps to control the resistance stability and a notch cut technique. The notch cut from the radiator is too used to reduce the size of the plane antenna. The measured -10 dB return loss bandwidth for the designed antenna is about 116.3% (8.7 GHz). The MIMO antenna does not require any additional structure to improve insulation. The proposed antenna supplies an acceptable radiation pattern and relatively flat gain over the entire frequency band.


Author(s):  
Muhammad Aslam Hasin ◽  
M. T. Ali ◽  
Hamizan Yong ◽  
Bazilah Baharom ◽  
Hadi Jumaat

This paper presents the design of adouble-sided Multiple-Input Multiple-Output (MIMO) antenna with a decoupling structure for Ultra-WideBand (UWB) applications. The proposed antenna consists of four square radiating elements printed on FR-4 substrate with partial slotted ground. The substrate consists of two sides and each side are consisting of two slotted partial ground and two square radiator antennas. The elements of the front side are orthogonal to the elements of the back side because it was to increase the isolation of the antenna. The front and back sides of the substrate were also presented with the decoupling structure to avoid the mutual coupling of each antenna. The results of simulated and measured of the proposed UWB MIMO antenna are observed and analyzed. The objective of the UWB MIMO antenna was achieved that large bandwidth of return loss below than -10 dB from 3.3 GHz to 11GHz with an insertion loss lower than -20 dB within the required frequency band. The proposed MIMO antennas exhibits a nearly Omni-directional radiation pattern with average gain value 4.36 dBi.


Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1174 ◽  
Author(s):  
Pawan Kumar ◽  
Shabana Urooj ◽  
Areej Malibari

This article presents a compact, planar, quad-port ultra-wideband (UWB) multiple-input–multiple-output (MIMO) antenna with wide axial ratio bandwidth (ARBW). The proposed MIMO design consists of four identical square-shaped antenna elements, where each element is made up of a circular slotted ground plane and feed by a 50 Ω microstrip line. The circular polarization is achieved using a protruding hexagonal stub from the ground plane. The four elements of the MIMO antenna are placed orthogonally to each other to obtain high inter-element isolation. FR-4 dielectric substrate of size 45 × 45 × 1.6 mm3 is used for the antenna prototype, and a good agreement is noticed among the simulated and experimental results. The proposed MIMO antenna shows 3-dB ARBW of 52% (3.8–6.5 GHz) and impedance bandwidth (S11 ≤ −10 dB) of 144% (2.2–13.5 GHz).


Author(s):  
Harleen Kaur ◽  
Hari Shankar Singh ◽  
Rahul Upadhyay

Abstract In this research study, a compact dual-polarized co-radiator ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with improved impedance bandwidth and isolation is proposed for wireless applications. The designed co-radiator has an overall area of 0.3λo × 0.3λo mm2 (where, λo is free space wavelength corresponding to the lower cut-off frequency, i.e., 3.1 GHz). The proposed resonator comprises of a hybrid geometry which is created with the combinations of a circular-shaped patch, a square, and two rectangular stubs. It is centrally aligned between two 50 Ω micro-strip feed lines that are positioned orthogonal to each other. Further, the modified ground plane is attached with the end-loaded line which provides broadband isolation over entire UWB frequency band. The simulated results of the proposed antenna exhibit wideband characteristics with impedance bandwidth of 3.1–16.9 GHz with minimum isolation of −15 dB. Moreover, all the radiation performance parameters are analyzed and discussed. Some important diversity parameters such as envelope correlation coefficient, mean effective gain, effective diversity gain, and channel capacity loss have also been evaluated. Furthermore, all the measured results of proposed antenna agree well with the simulated results which make the proposed antenna a suitable candidate for UWB-MIMO wireless applications.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sachin Kumar Yadav ◽  
Amanpreet Kaur ◽  
Rajesh Khanna

Abstract In this article, cross-shaped metallic parasitic strips based two radiator element multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is excited by quadrature wave transformer microstrip feedline, designed, simulated and fabricated for ultra-wideband (UWB) applications. The proposed MIMO antenna structure is implemented with the help of two rectangular-shaped radiator elements that supports three modes HE11δ , HE21δ , and HE12δ at 4.4, 8.3, 10.8 GHz respectively. These fundamental and higher-order modes are supported to wide impedance bandwidth. Inverted T-shaped metallic strip and ground stub to improve the impedance bandwidth 104.6% (3.3–10.8 GHz) with 5.7 dBi peak gain, to enhance the coupling coefficient by stub, scissor-shaped defected ground structure and cross-shaped metallic parasitic strips are used in the existed structure. The MIMO diversity parameters are implemented as simulated ECC ≤ 0.003, DG ≥ 9.98 dB, and CCL ≤ 0.68. All the obtained MIMO antenna parameters are within the acceptable limit for providing high data rate for UWB applications.


2020 ◽  
Vol 10 (5) ◽  
pp. 1715
Author(s):  
Pawan Kumar ◽  
Shabana Urooj ◽  
Fadwa Alrowais

A planar, microstrip line-fed, quad-port, multiple-input-multiple-output (MIMO) antenna with dual-band rejection features is proposed for ultra-wideband (UWB) applications. The proposed MIMO antenna design consists of four identical octagonal-shaped radiating elements, which are placed orthogonally to each other. The dual-band rejection property (3.5 GHz and 5.5 GHz corresponding to Wi-MAX and WLAN bands) was obtained by introducing a hexagonal-shaped complementary split-ring resonator (HCSRR) in the radiators of the designed antenna. The MIMO antenna was etched on low-cost FR-4 dielectric substrate of size 58 × 58 × 0.8 mm3. Isolation higher than 18 dB and envelope correlation coefficient (ECC) lesser than 0.07 was observed for the MIMO/diversity antenna in the operating range of 3–16 GHz. The presented four-port UWB MIMO antenna configuration was fabricated, and the experimental results validate the simulation outcomes.


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