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This paper proposes a 10 × 10 MIMO multiband broadband planar antenna for tablets or laptops. The designed antennas cover a large number of the popular sub‐6‐GHz application bands, such as 0.617–0.96, 2.1–2.7, 3.5–4.5, and 6.1–7.2 GHz for public safety communications, radio systems, Bluetooth, Wi‐Fi, and satellite communications. The proposed antenna is designed with grounded branches, which can generate a wide bandwidth and cover most of the sub‐6‐GHz application band by coupling between branches of different lengths and antennas. MIMO antennas have been measured to have an envelope correlation coefficient of less than 0.7 and have met the standards set by international organizations for human radiation absorption simulations. The proposed antenna validates the unique 10 × 10 MIMO antenna structure and feasibility. Multiple operable frequency bands are realized, and the radiation effect of the antenna on the human body is analyzed if it complies with international market standards. The proposed antenna design is well suited for multiband and broadband requirements. [ABSTRACT FROM AUTHOR]

A broadband radiation dual‐polarized antenna is proposed for the application of 5G sub‐6 GHz base stations. The radiator of the antenna is consisted of a pair of crisscrossed sector dipoles, and is fed by microstrip stubs. By etching rectangular slots on the patches, the resonant modes of the antenna can increase to eight. Therefore, the broadband characteristic can be realized by effectively exciting the ideal modes. And the dual‐polarized characteristic is also achieved by exciting the ideal modes. The overall size of the proposed antenna is λ×λ×0.258λ (λ is the free‐space wavelength at 4.3 GHz) and it is fabricated and tested. The measured bandwidth can achieve 47.2% (3.19 ~ 5.22 GHz) for S11 <−10 dB and S21 < −26 dB, and the half‐power beam width (HPBW) is 55 ± 6° within the working band. The antenna gain attains 8.3 ± 1.6 dBi with a good stable radiation pattern. These features make the antenna more attractive for 5G sub‐6 GHz communication applications. [ABSTRACT FROM AUTHOR]

In this article, compact inverted F‐antennas (IFAs) operating in the 3.5 GHz band is proposed for future 5G smartphone applications. The conventional IFA is modified to make the structure compact and efficient. The additional IFAs are aligned in face‐to‐face configuration to reduce the coupling between them up to some extent. Furthermore, a novel decoupling element is incorporated between antenna pairs to effectively enhance the isolation. As a result, the proposed building block exhibits isolation higher than 28.2 dB between two adjacent ports. Based on highly isolated building blocks, a 4 × 4 and 8 × 8 multi‐input multi‐output (MIMO) antenna array is designed and investigated which is operated in 3.5 GHz (LTE band 42). The proposed 8 × 8 MIMO antenna array has four compact building blocks and reserves sufficient space for integrating other antennas such as 2G/3G/4G antennas. To validate the simulated results, a prototype of the proposed antenna is fabricated and tested. Over the entire operating frequency, the fabricated 8 × 8 MIMO antenna array obtain high isolation of more than 27.3 dB, and high antenna efficiency (>61%). Also, its corresponding measured envelope correlation coefficients are lower than 0.04 and channel capacity was about 39.1–40.6 bps/Hz. The measured results show that the proposed MIMO antenna array is a good candidate for future fifth‐generation smartphone applications. [ABSTRACT FROM AUTHOR]

A multi‐band, small, high gain, low specific absorption rate (SAR), and circularly polarized (CP) textile wearable antenna fed using aperture coupled technique is designed on two layers of denim (εr=1.2, h = 0.787 mm as feeding layer) and felt (εr=1.3, h = 1.5 mm as a resonating layer) textile substrates. The antenna is designed on two layers with two relative permittivities to enhance the BW and reduce the negative mutual coupling. Afterward, another layer of denim with the complete ground of ShieldIt conductor is added to decrease the SAR value along with the directive gain. The antenna works for Industrial, Scientific, and Medical (ISM), 5G, and sub‐6 GHz communication systems as it operates at 2.45–2.55 GHz and 3.8 GHz (3.6–4.15 GHz), and 5.6 GHz (5.55–5.65 GHz), respectively. The proposed antenna has the maximum directive gain of 8.35 dBi, acceptable SAR values at a 10 mm distance from the human body for both standards. In addition, the antenna's CP is examined, showing AR values of <2.5 dB at the working BW. Finally, the proposed antenna is measured and compared with the simulation results. A good agreement exists between simulation and measurement results. [ABSTRACT FROM AUTHOR]

A compacted dual‐polarized base station antenna with filtering characteristics and enhanced broadband is proposed for sub‐6 GHz applications in this letter. The lower stopband radiation null is thus generated by the parasitic loops on the back of the substrate. In order to achieve the filtering response and extend the bandwidth of at the upper edge of the passband, a split strip‐type dipole arm is added to the inner part of the annular dipole to form the radiation null. On the flip side, by changing the shape of the Balun ground, another filtering null is generated at the upper‐band to suppress the second harmonic, achieving better broadband suppression performance. The experimental results show that the antenna has a 42.9% (3.3–5.1 GHz) impedance bandwidth, and the in‐band average gain reaches 8.3 dBi, while the out‐of‐band gain suppression is greater than 17 dB. [ABSTRACT FROM AUTHOR]

In this article, a compact dual‐band antenna is presented for sub‐6 GHz base station applications. The main radiator of the antenna is composed of ring‐shaped dipoles and Y‐shaped dipoles. Broadband impedance matching is achieved by complementarily coupling between the two types of dipoles. The measured results show the bandwidth of the proposed antenna can cover from 2.06 to 3.69 GHz in the low‐frequency band with an around isolation of 30 dB, and cover from 4.79 to 5.02 GHz in the high‐frequency band with an around isolation of 25 dB. The in‐band peak realized gain is 9.12 ± 1.02 dBi. Since the proposed antenna operates at N41, N78, and N79 bands in China, it can be a potential element for full sub‐6 GHz base station applications. [ABSTRACT FROM AUTHOR]

A compact dual‐band antenna is designed in this paper, which consists of a pair of lower band (LB) element and four higher band (HB) elements operating at 0.69 to 0.96 GHz and 3.3 to 3.6 GHz, respectively. Four HB elements are put between the adjacent dipole arms of LB element. All of elements are at the same height, and having their own reflector. A designed dual‐band dual‐polarized antenna at high frequency ratio will be fulfilled without added any other structure. The fabricated antenna sample has been measured, results show that the average gains of LB and HB elements are 8.48 dBi and 8.44 dBi and the half power beam widths are 69.1° ± 9° and 60.7° ± 8.5°, respectively. Moreover, dual‐polarized property of both LB and HB is checked. The cross‐polarization discrimination values are greater than 15 dB. The proposed antenna is implemented the coverage of two bands with high frequency ratio with a simple structure, and the antenna with both low profile and high gain characteristics. All of the results demonstrate that the antenna radiation boasts its favorable performance and can be a good candidate in 5G mobile communication system for sub‐6 GHz base stations. [ABSTRACT FROM AUTHOR]

In this article, a dual‐band circularly polarized multiple‐input‐multiple‐output (MIMO) dielectric resonator antenna (DRA) is proposed for 3.5 and 5.5 GHz bands, both being located under 6 GHz. Known as sub‐6 (or as mid‐band), they provide good coverage and capacity in the newly targeted fifth‐generation (5G) systems. The proposed structure consists of two ring DRAs (RDRAs) etched on a 0.8 mm thick RT Duroid substrate. Measured impedance bandwidths in broadside direction are 3.1‐3.75 GHz (19%) and 5.3‐5.6 GHz (9.4%) and circular polarization (CP) bandwidths are 3.425‐3.6 GHz (5%) and 5.45‐5.55 GHz (2%), respectively. CP is achieved by exciting HE modes using two probes placed orthogonaly to each other, that is, at an azimuthal angular distance of 90∘. Varying the lengths of the probe allows achieving the necessary time‐phase quadrature between modes. Comparison between recent multiband circularly polarized MIMO DRAs and proposed prototype has revealed that CP bandwidth in both bands is one of the highlighting advantages of the present configuration. [ABSTRACT FROM AUTHOR]

A method to tilt the beam of a planar antenna in the E‐plane is demonstrated by implementing a metamaterial (MM) structure onto the antenna substrate at the fifth‐generation (5G) band of 3.5 GHz. The beam tilting is achieved due to the phase change that occurs when the electromagnetic (EM) wave traverses through two media with different refractive indices. A new adjacent square‐shaped resonator (ASSR) structure is proposed to achieve the beam tilting in a dipole antenna. This structure provides a very low loss of −0.2 dB at 3.17 GHz. The simulation and measurement results illustrate that the radiation beam of the dipole antenna is tilted by +25° and −24° depending on the position of the ASSR array onto the dipole antenna substrate. In addition, no degradation in the gain is observed as in the conventional beam‐tilting methods; in fact, gain enhancement values of 3 dB (positive deflection) and 2.7 dB (negative deflection) are obtained compared with that of a dipole antenna with no ASSR array. The reflection coefficient of the dipole antenna with ASSR array has a good agreement with that of the dipole antenna with no ASSR array. The measured results agree well with the simulated ones. [ABSTRACT FROM AUTHOR]

A metal‐frame‐integrated eight‐antenna array operating in the long term evolution bands 41/42/43 (2.496 GHz‐2.69 GHz, 3.4 GHz‐3.8 GHz) for future fifth generation multiple‐input multiple‐output (MIMO) applications in smartphones is presented and discussed. The proposed eight‐antenna MIMO array is formed by integrating four identical building blocks, each of which consists two dual‐mode monopole antenna elements with a neutralization line (NL) embedded in between. Part of the metal frame is exploited to increase the effective resonant length of the monopole antenna. By using the wideband NL, two transmission dips can be generated, and thus an improved isolation (>10 dB) is achieved. The proposed antenna array was simulated and experimentally tested. Good antenna efficiency (>44%) and low envelope correlation coefficient (<0.2) were obtained in the bands of interest. In an 8 × 8 MIMO system with 20 dB signal‐to‐noise ratio, the calculated ergodic channel capacity was as high as 38 bps/Hz in the low band, and 38.3 bps/Hz in the high band. Details of the proposed antenna array are described. The simulated, measured, and calculated results are presented. [ABSTRACT FROM AUTHOR]