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Simulated 3D radiation pattern for both antenna elements a Port 1: top antenna b Port 2: bottom antenna
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A planar printed multi-input-multiple-output (MIMO) antenna with pattern diversity is proposed. The two printed dipole-like radiators have omnidirectional radiation patterns in the orthogonal planes. The antennas are printed on the opposite sides of a dielectric substrate, which makes it a compact MIMO system with excellent isolation between the an...
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This paper presents a dual-band eight-element multiple-input multiple-output (MIMO) antenna for 5G applications. The 8-element antenna is formed into two 4 × 4 MIMO systems that operate at 2500–2600 MHz and 1800–2200 MHz bands. The antenna elements are mounted along the perimeter of a rectangular ground plane with a total size of 110 × 80 mm² andar...
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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 tw...
Citations
... However, some MIMO antennas are designed for the WLAN band (2.4/5.8 GHz) [23][24][25][26]. Polarization and pattern diversity, on the other hand, appear to be promising techniques for decreasing the correlation between antenna far-fields without increasing the circuit dimension. ...
The proposed work describes a corner square-cut square-patch multiple-input multiple-output (MIMO) antenna with reduced mutual coupling for circular polarization (CP). A two-port MIMO-CP antenna was designed and operated at 5.6 GHz for wireless local area network (WLAN) applications. The dimensions of the MIMO-CP antenna were 22.5×50mm2(0.43λ0×0.933λ0) and the FR4 substrate height was 1.6 mm. Between the two-elements, the edge-to-edge distance was 12.2 mm (0.227 λ0), where λ0 was the free space wavelength at 5.6 GHz. A slot was created in the middle of the ground in the proposed MIMO antenna to reduce mutual coupling and improve CP. The ground slot improves impedance matching and provides a better S-parameter and axial ratio (AR), according to the antenna results. According to the simulated results, the proposed antenna bandwidth of 5.23–6.42 GHz (21.4%) for S11 were <−10 dB, isolation was −37 dB with a peak gain of 6 dB and AR ≤3 dB from 5.37 to 5.72 GHz (6.25%). The proposed antennas are simple to fabricate, have low profiles, are inexpensive, have good isolation, and are CP. The diversity gain (DG) and envelop correlation coefficient (ECC) results are better in the simulated frequency band. A MIMO-CP antenna geometry prototype is built and measured for comparison, yielding good results when compared to the simulated and measured results. The MIMO-CP antenna, as designed, is suitable for WLAN applications.
... However, some MIMO antennas are designed for the WLAN band (2.4/5.8 GHz) [23][24][25][26]. Polarization and pattern diversity, on the other hand, appear to be promising techniques for decreasing the correlation between antenna far-fields without increasing the circuit dimension. ...
The proposed work describes a corner square-cut square-patch multiple-input multiple-output (MIMO) antenna with reduced mutual coupling for circular polarization (CP). A two-port MIMO-CP antenna was designed and operated at 5.6 GHz for wireless local area network (WLAN) applications. The dimensions of the MIMO-CP antenna were 22.5×50mm2(0.43λ0×0.933λ0) and the FR4 substrate height was 1.6 mm. Between the two-elements, the edge-to-edge distance was 12.2 mm (0.227 λ0), where λ0 was the free space wavelength at 5.6 GHz. A slot was created in the middle of the ground in the proposed MIMO antenna to reduce mutual coupling and improve CP. The ground slot improves impedance matching and provides a better S-parameter and axial ratio (AR), according to the antenna results. According to the simulated results, the proposed antenna bandwidth of 5.23–6.42 GHz (21.4%) for S11 were <−10 dB, isolation was −37 dB with a peak gain of 6 dB and AR ≤3 dB from 5.37 to 5.72 GHz (6.25%). The proposed antennas are simple to fabricate, have low profiles, are inexpensive, have good isolation, and are CP. The diversity gain (DG) and envelop correlation coefficient (ECC) results are better in the simulated frequency band. A MIMO-CP antenna geometry prototype is built and measured for comparison, yielding good results when compared to the simulated and measured results. The MIMO-CP antenna, as designed, is suitable for WLAN applications.
... Besides port-isolation and spatial diversity, MIMO antennas also require diversity in terms of radiation pattern, polarisation, frequency, etc. to ensure interference-free reliable MIMO operation. Malik et al. (2016) designed a two-port MIMO for 2.4 GHz with omnidirectional pattern diversity using two orthogonally placed dipole radiators. Fang et al. (2017) designed another two-element MIMO with pattern diversity for WLAN bands (2.4/5.5 GHz) using two oppositely placed printed inverted-F radiators. ...
A four-element multiple-input-multiple-output (MIMO) antenna has been designed to operate at triple wide bands with improved port-isolation and polarization diversity. The resonant modes of the MIMO are achieved by meander slot loaded elliptical shaped fundamental radiators and the inter-port isolation is achieved by employing neutralizing line embedded ground plane. Apart from port-isolation, the proposed MIMO also offers polarization diversity at different operating bands. The triple-band MIMO offers linear polarized radiation at WLAN band (4.2-5.6 GHz), right hand circular polarized (RHCP) radiation at C-band (6.3-7.5 GHz) and left hand circular polarized (LHCP) radiation at X-band (8.7-9.3 GHz). The overall isolation (>27 dB), envelope correlation co-efficient (ECC<0.0005), diversity gain (DG>9.9995), mean effective gain (MEG<0.734 dB), total active reflection co-efficient (TARC<-20 dB) and channel capacity loss (CCL<0.35 bits/S/Hz) meet the criteria for reliable MIMO operation. The proposed MIMO has been fabricated on 55.6×55.6×1.6 mm³ piece of FR-4 epoxy substrate after simulation and measured in VNA. Adequate similarity can be observed between the measured and simulated results.
... In recent years, several multiband and ultra-wideband (UWB) MIMO antennas [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] have been designed. Most of the MIMO antennas designed are initiated by designing a unit radiator first and then repeating the unit radiator several times to design two-element [1][2][3][4][5][6][7][8] or four-element [9][10][11][12][13][14][15] MIMOs. ...
... In recent years, several multiband and ultra-wideband (UWB) MIMO antennas [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] have been designed. Most of the MIMO antennas designed are initiated by designing a unit radiator first and then repeating the unit radiator several times to design two-element [1][2][3][4][5][6][7][8] or four-element [9][10][11][12][13][14][15] MIMOs. Unit radiators are basically single-element antennas that are generally designed for multiband [16][17][18][19][20] or UWB [21][22][23][24] resonance. ...
... monopole [18], metamaterial resonator [19], CPW-fed monopole [20] etc. UWB antennas are designed utilizing the advancement of tapered CPW [25][26][27] and tapered patches such as trapezoidal [21][22][23][24][25], elliptical [23], hexagonal [27], triangular [26] etc. The unit radiators of multiband MIMOs [1][2][3][4]7,11,12,15] and UWB MIMOs [5,6,[8][9][10]13,14] suffer mutual coupling because of close proximity which degrades the overall performance of MIMO operation. To minimize this effect of mutual coupling several techniques have been applied such as slots [1,[4][5][6][9][10][11]15], decoupling strips [6,8], neutralizingline [14], meta-structure [2] etc. ...
A two-element MIMO antenna, with improved isolation and pattern diversity, is designed and presented. The dual-band MIMO covers both the adjacent upper WLAN (5.2 GHz) and WiMAX (5.8 GHz) bands with clear isolation between them. The unit radiator of the MIMO is a co-planar waveguide-fed trapezoidal patch that achieves its resonant modes by adjusting the slope of the non-parallel sides. A frequency selective meta-structure is placed in-between the two radiating elements to reduce the mutual coupling and achieve pattern diversity. The MIMO offers peak gains of 1.56 and 5.16 dB at 5.2 GHz (5.1–5.34 GHz) and 5.8 GHz (5.68–5.9 GHz), respectively. The port-isolations achieved at WLAN and WiMAX bands are 26 and 23 dB, respectively. The correlation co-efficient (ECC < 0.05), diversity gain (DG > 9.99) and channel capacity loss (CCL < 0.03) also adhere to the criteria for MIMO operation. The measured results are in good agreement with the simulated ones.
... Introducing multiple-input multiple-output (MIMO) systems for cellular 5G and vehicle-to-everything (V2X) applications is essential to meeting the requirements of the upcoming autonomous wireless communication systems in the automotive industry. A MIMO system consists of multiple antennas at receiver and transmitter sides which allows it to increase the channel capacity, data rate, and the total throughput of the system without increasing the operating frequency band or the transmit power [1]. MIMO system also has the benefits of high reliability and low latency in a high electromagnetic scattering environment by using multiple antenna elements that transmit and/or receive independent channels assuming that these elements are highly isolated or uncorrelated [2]. ...
... However, this improvement only works when the efficiency of each antenna element is better than 60%. The third method, which is used in this paper, analyzes the radiation patterns of the be summarized in Equation (1) [3,5,8]: ...
... The ECC and DG values for this MIMO antenna system at 5G and V2X frequencies have been calculated using a MATLAB script for Equation (1) and Equation (2) for simulation and chamber measurements. Fig. 7 shows these calculations, and it can be noticed that the worst-case value of ECC is around 0.1 at the low frequency band since lower frequency signals support longer wavelengths which require more spacing. ...
Various multiple-input multiple-output (MIMO) antenna systems for automotive applications are presented in this paper using two uniquely designed elements: 1) a low profile wideband Planar Inverted-F antenna (PIFA), and 2) a compact wideband monopole in the sub-6 GHz 5G systems and Vehicle-to-Everything (V2X) communications that cover the frequency range from 617 MHz to 6 GHz. The proposed MIMO systems can be used in a low-profile or shark fin style housing placed on the vehicle’s roof. Each MIMO system achieves satisfactory performance across the whole band with suitable physical dimensions. The envelope correlation coefficient (ECC) and diversity gain (DG) are calculated using MATLAB in each MIMO configuration as they represent the two key factors in the MIMO performance. Simulation results are presented along with measured data on a 1-meter rollededge ground plane (GND) and on a vehicle’s roof from properly cut metal sheet prototypes. The results are discussed in terms of VSWR, passive isolation between elements, combined radiation patterns, port-efficiencies, ECC, and DG.
... Thus, several isolation techniques have been used to mitigate the mutual coupling effect of MIMO elements in a confined space. Among them are the use of parasitic structures [1], modified ground planes [2], orthogonally-oriented elements [3,4], metamaterial structures [5,6]. Radiation diversity has also proved to be an effective isolation technique [7][8][9]. ...
A low-profile monopole microstrip antennas with multiple-input-multiple-output (MIMO) configuration for a 4G/5G communication terminal is presented. The MIMO antenna system consists of four elements that operate in the LTE1800/2600 and GSM1800 bands. The antenna elements are mounted along the four sides of a rectangular ground plane of size 120×100 mm 2. Spatial diversity technique and a modified ground plane are used to enhance isolation between elements. To mitigate the mutual coupling effect, the lower corners of the ground plane have been truncated. The measured isolation is lower than-17 dB between any two elements over the operating frequency bands. The total efficiency ranges from 69% to 83% and from 73% to 86% over LTE1800 and LTE2600 bands, respectively. The diversity performance of the measured envelope correlation coefficient (ECC) and radiation patterns meet the diversity criteria for 4/5G networks.
... The measured values are 0.0005 at 0.9 GHz, 0.0003 at 1.8 GHz, and 0.0064 at 2.3 GHz, respectively. The results are inaccurate because the MIMO system is assumed to be operating in a uniform multipath environment [30]. Ideally, ECC is calculated by 3D radiation patterns [30] using Equation (9) [31] where F → j (θ, φ) is the normalized complex radiation pattern vector of the j th port [32], and symbols and * denote the Hermitian product and complex conjugate, respectively [33]. ...
... The results are inaccurate because the MIMO system is assumed to be operating in a uniform multipath environment [30]. Ideally, ECC is calculated by 3D radiation patterns [30] using Equation (9) [31] where F → j (θ, φ) is the normalized complex radiation pattern vector of the j th port [32], and symbols and * denote the Hermitian product and complex conjugate, respectively [33]. The measured 3D radiation patterns with a step of 1°using Equation (9) is 0.09, 0.05 and 0.02 at each mentioned frequency, respectively. ...
In this paper, a triple band Multiple-Input Multiple-Output (MIMO) Rectangular Dielectric Resonator Antenna (RDRA) designed using hybrid techniques for Long Term Evolution (LTE) applications is investigated and presented. The proposed MIMO antenna can transmit and receive data independently by covering LTE Band 8 at 0.9 GHz, LTE Band 3 at 1.8 GHz, and LTE Band 40 at 2.3 GHz. Hybrid technique is adopted in this design by combining a meander line antenna with an RDRA to realize multiband operation. Meander line antenna has been proposed over the long vertical microstrip feeding line at 0.9 GHz, to employ a size reduction in the antenna, while two modes of RDRA are applied in this design: TE1δ1y mode at 1.8 GHz and TE2δ1y mode at 2.3 GHz. The proposed MIMO antenna has been fabricated and experimentally tested. The measured impedance bandwidths (S11<-10 dB) for the three stated bands are 4.40%, 11.36%, and 2.54% at Port 1, respectively and 5.47%, 10.54%, and 3.43% at Port 2, respectively. Measured isolations of -15.3 dB, -17.8 dB, and -47.0 dB are obtained at each described frequency, respectively. The performance of the proposed MIMO antenna is further validated using over-the-air LTE downlink throughput test. Throughputs of 93.16 Mbps, 93.01 Mbps, and 87.30 Mbps have been achieved for 0.9 GHz, 1.8 GHz, and 2.3 GHz, respectively, using 64 Quadrature Amplitude Modulation (QAM). In this regard, it is conceived that the proposed MIMO antenna can be a good candidate for LTE applications due to the validated excellent throughput performance.
... Therefore, in the design process of antennas tendency towards using approaches such as PRS or metamaterial structures which improve antenna bandwidth [1][2][3][4] and gain [5][6][7][8] has increased. Moreover, there has been an increase in using MIMO technology [9][10][11][12][13][14][15] due to capabilities such as high data transfer. ...
... In LTE network, MIMO antenna is commonly used as a way to increase data rate. MIMO antenna suitable for indoor repeater is MIMO antenna that has omnidirectional radiation pattern (Ching-song, Hsu, Chun, Engineering, Rd, & Shiang, 2013;Fang, Sun, & Chuang, 2014;Malik, Kartikeyan, & Nagpal, 2016;Moradikordalivand, Rahman, & Khalily, 2014). Therefore, we proposed a MIMO omnidirectional antenna that has high gain, where in every antenna is microstrip monopole collinear antenna. ...
To increase reception in Long Term Evolution (LTE) network inside a building, a repeater is needed. The antenna used in the repeater inside the building is usually a high gain antenna with omnidirectional radiation pattern. Meanwhile, to increase data rate in LTE, one of methods used is by using Multiple Input Multiple Output (MIMO) antenna. In this paper, the omnidirectional MIMO antenna at 1.8 GHz for LTE applications has been designed and realised. The single element of this MIMO antenna is a collinear microstrip antenna array. The design and simulation were done using 3D electromagnetic simulator software, while antenna realisation was done using FR4 microstrip with a thickness of 1.6 mm and permittivity of 4.4. The measurement results showed that this antenna has 359 MHz bandwidth in frequency range at 1.6-1.9 GHz, with a return loss less than -10 dB. The antenna gain is around 7.4 to 8.7 dBi with omnidirectional radiation pattern and mutual coupling is around -22 dB to -27 dB.
... Fig. 4(a) shows the second MIMO system under consideration which comprises of two halfwavelength dipoles, one oriented along z-direction, another along x direction. Such orthogonal arrangements are useful for achieving omnidirectional pattern diversity as suggested in [32]. The dimensions of the dipoles and inter-element spacing is kept as same as that for the parallel side-by-side scenario. ...
In this paper, the concept of cross-correlation Green's functions (CGF) is used in conjunction with the finite difference time domain (FDTD) technique for calculation of envelope correlation coefficient (ECC) of any arbitrary MIMO antenna system over wide frequency band. Both frequency-domain (FD) and time-domain (TD) post-processing techniques are proposed for possible application with this FDTD-CGF scheme. The FDTD-CGF time-domain (FDTD-CGF-TD) scheme utilizes time-domain signal processing methods and exhibits significant reduction in ECC computation time as compared to the FDTD-CGF frequency domain (FDTD-CGF-FD) scheme, for high frequency-resolution requirements. The proposed FDTD-CGF based schemes can be applied for accurate and fast prediction of wideband ECC response, instead of the conventional scattering parameter based techniques which have several limitations. Numerical examples of the proposed FDTD-CGF techniques are provided for two-element MIMO systems involving thin-wire half-wavelength dipoles in parallel side-by-side as well as orthogonal arrangements. The results obtained from the FDTD-CGF techniques are compared with results from commercial electromagnetic solver Ansys HFSS, to verify the validity of proposed approach.
