A high-isolation eight-antenna multi-input multi-output (MIMO) array operating in the 3.5 GHz band (3.4-3.6 GHz) for future smartphones is proposed. Here, a novel balanced open-slot antenna is ...designed as an array antenna element, in which this antenna design can yield a balanced slot mode (with reduced ground effects) that can enhance the isolation between two adjacent input ports. Furthermore, by meticulously arranging the positions of the eight antenna elements, desirable polarization diversity can also be successfully achieved, which further mitigates the coupling between antenna elements. A prototype was manufactured to validate the simulation. A good impedance matching (return loss > 10 dB), high isolation (>17.5 dB), high total efficiency (>62%), and low envelope correlation coefficient (ECC, <0.05) were measured across the desired operation bandwidth. To verify the MIMO performance, ergodic channel capacity using the Kronecker channel model was calculated. The effects of hand phantom were also studied.
The design of a novel practical 28 GHz beam steering phased array antenna for future fifth generation mobile device applications is presented in this communication. The proposed array antenna has 16 ...cavity-backed slot antenna elements that are implemented via the metallic back casing of the mobile device, in which two eight-element phased arrays are built on the left- and right-side edges of the mobile device. Each eight-element phased array can yield beam steering at broadside and gain of >15 dBi can be achieved at boresight. The measured 10 dB return loss bandwidth of the proposed cavity-backed slot antenna element was approximately 27.5-30 GHz. In addition, the impacts of user's hand effects are also investigated.
In this paper, a compact building block composed of a slot antenna and a loop antenna is proposed. The slot antenna and the loop antenna share a rectangular clearance, which improves the compactness ...of the building block effectively. Although the slot and the loop have overlapped completely, the proposed building block exhibits good isolation (better than 19 dB) without any external decoupling structure. Four such building blocks are used to implement a compact eight-port multiple-input multiple-output (MIMO) array operating at 3.5 GHz band (3.4-3.6 GHz) for fifth-generation (5G) metal-rimmed smartphone applications. The proposed eight-antenna MIMO array exhibits good isolation of better than 16 dB across the whole operating band. The measured efficiencies of the proposed MIMO array were between 59% and 73%, and its corresponding measured envelope correlation coefficients (ECCs) were better than 0.05. Furthermore, the calculated channel capacity of the proposed MIMO array with 20 dB signal-to-noise ratio (SNR) was about 38.2-39.8 bps/Hz across the desired bands (3.4-3.6 GHz). The measured results confirm that the proposed MIMO array is a good candidate for 5G terminals.
A 12-port antenna array operating in the long term evolution (LTE) band 42 (3400-3600 MHz), LTE band 43 (3600-3800 MHz), and LTE band 46 (5150-5925 MHz) for 5G massive multiple-input multiple-output ...(MIMO) applications in mobile handsets is presented. The proposed MIMO antenna is composed of three different antenna element types, namely, inverted <inline-formula> <tex-math notation="LaTeX">\pi </tex-math></inline-formula>-shaped antenna, longer inverted L-shaped open slot antenna, and shorter inverted L-shaped open slot antenna. In total, eight antenna elements are used for the <inline-formula> <tex-math notation="LaTeX">8 \times 8 </tex-math></inline-formula> MIMO in LTE bands 42/43, and six antenna elements are designed for the <inline-formula> <tex-math notation="LaTeX">6 \times 6 </tex-math></inline-formula> MIMO in LTE band 46. The proposed antenna was simulated, and a prototype was fabricated and tested. The measured results show that the LTE bands 42/43/46 are satisfied with reflection coefficient better than −6 dB, isolation lower than −12 dB, and total efficiencies of higher than 40%. In addition to that, the proposed antenna array has also shown good MIMO performances with an envelope correlation coefficient lower than 0.15, and ergodic channel capacities higher than 34 and 26.5 b/s/Hz in the LTE bands 42/43 and LTE band 46, respectively. The hand phantom effects are also investigated, and the results show that the proposed antenna array can still exhibit good radiation and MIMO performances when operating under data mode and read mode conditions.
A multi-band 10-antenna array working at the sub-6-GHz spectrum (LTE bands 42/43 and LTE band 46) for massive multiple-input multiple-output (MIMO) applications in future 5G smartphones is proposed. ...To realize <inline-formula> <tex-math notation="LaTeX">10\times 10 </tex-math></inline-formula> MIMO applications in three LTE bands, 10 T-shaped coupled-fed slot antenna elements that can excite dual resonant modes are integrated into a system circuit board. Spatial and polarization diversity techniques are implemented on these elements so that the improved isolation and mitigated coupling effects can be achieved. The proposed antenna array was manufactured and experimentally measured. Desirable antenna efficiencies of higher than 42% and 62% were measured in the low band and high band, respectively. Vital results, such as the envelope correlation coefficient, channel capacity, and mean effective gain ratio, have also been computed and analyzed. The calculated ergodic channel capacities of the <inline-formula> <tex-math notation="LaTeX">10\times 10 </tex-math></inline-formula> MIMO system working in the LTE bands 42/43 and LTE band 46 reached up to 48 and 51.4 b/s/Hz, respectively.
A compact size, coplanar waveguide (CPW) fed two‐antenna multiple input multiple output (MIMO) with high isolation and excellent impedance matching operating in n77/n78/n79 5G NR ...sub‐6 GHz/Wi‐Fi‐5/V2X/DSRC/Wi‐Fi‐6/INSAT‐C is proposed for future wireless applications. Each antenna element is a CPW‐fed antenna type composed of an “inverted‐A,” “y‐shaped,” and “small extended stub” structures. The two‐antennas are deployed in the same orientation at an edge‐to‐edge distance of 0.06λ (λ represents free‐space wavelength at 3.70 GHz) on a shared rectangular substrate having designed footprint of 0.57λ × 0.39λ. To attain high isolation of greater than 20 dB in the desired bands of interest, a novel comb‐shaped isolating structure is deployed between the two antenna elements. From the measured results, the proposed MIMO antenna has exhibited wide 10‐dB impedance bandwidth of 88.57% (3.00‐7.70 GHz), good gain above 3 dBi and efficiency larger than 78% throughout the desired operating bands. Moreover, the MIMO diversity performance metrics including envelope correlation coefficient (ECC), diversity gain (DG), mean effective gain (MEG), total active reflection coefficient (TARC), channel capacity and channel capacity loss (CCL) are also achieved.
A dual-polarized hybrid eight-antenna array operating in the 2.6-GHz band (2550-2650 MHz) for 5G communication multi-input multi-output (MIMO) operation in the smartphone is presented. The proposed ...hybrid antenna array elements are symmetrically placed along the long edges of the smartphone, and they are composed of two different four-antenna array types (C-shaped coupled-fed and L-shaped monopole slot) that exhibit orthogonal polarization. Therefore, coupling between the two antenna array types can be reduced, and the MIMO system performances are enhanced. A prototype of the proposed eight-antenna array is manufactured and measured. A good impedance matching (10 dB return loss or better), desirable cross-polarization discrimination (better than 15 dB), and an acceptable isolation (better than 12.5 dB) are obtained. Envelope correlation coefficient and channel capacity are also calculated to evaluate the MIMO performances of the proposed antenna array.
An 8-element dual-band multiple-input-multiple-output (MIMO) antenna operating in the 5G New Radio band n77 (3300-4200 MHz) and 5 GHz band (4800-5000 MHz) in mobile handsets is presented. The ...8-element MIMO antenna is formed by employing four sets of dual-antenna arrays (DAAs) that are symmetrically printed along the two long side-edge frames of the smartphone. Each DAA is composed of two double-branch monopoles and a T-shaped decoupling stub, in which good mutual coupling reduction can be realized via the decoupling structures. Furthermore, the decoupling structures can also aid in improving the impedance matching of the array units for achieving wideband operation.
A tri-polarized antenna with diverse radiation characteristics is proposed in this paper. This design mainly consists of two pairs of loop radiating dipoles and an omnidirectional monopole antenna ...element, which are used for the fifth generation (5G) and vehicle to everything (V2X) communications, respectively. By adding eight pairs of inverted L-shaped patches with unequal sizes around the proposed dipoles, wide beamwidths in both E- and H-planes can be obtained across the desired lower and upper frequency bands. Furthermore, by employing eight fork-shaped microstrip stubs to combine the circular monopole antenna element and the L-shaped patches, the flare angle of the conical beam can be increased to 180<inline-formula><tex-math notation="LaTeX">^{\circ }</tex-math></inline-formula>, which results in gain enhancement in the azimuth plane. Finally, the proposed loop radiating dipoles are excited by a pair of symmetrical differentially-fed feeding lines. Consequently, high port isolation for the proposed loop radiating dipoles as well as low gain variations for the monopole antenna element can be achieved. Measured results show that the impedance bandwidths of 32.84<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> (2.8-3.9 GHz) and 18.18<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> (4.5-5.4 GHz) can be achieved for the 5G communications. Wide half power beamwidths (HPBW) of larger than 103<inline-formula><tex-math notation="LaTeX">^{\circ }</tex-math></inline-formula> in E-plane and 91<inline-formula><tex-math notation="LaTeX">^{\circ }</tex-math></inline-formula> in H-plane can be achieved across the operating bands. In addition, a bandwidth of 5.5<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> (5.82-6.15 GHz) with gain of 2.47 <inline-formula><tex-math notation="LaTeX">\pm</tex-math></inline-formula> 0.69 dBi in the azimuth plane can also be obtained for V2X communications.
A hybrid antenna is proposed for future 4G/5G multiple input multiple output (MIMO) applications. The proposed antenna is composed of two antenna modules, namely, 4G antenna module and 5G antenna ...module. The 4G antenna module is a two-antenna array capable of covering the GSM850/900/1800/1900, UMTS2100, and LTE2300/2500 operating bands, while the 5G antenna module is an eight-antenna array operating in the 3.5-GHz band capable of covering the C-band (3400-3600 MHz), which could meet the demand of future 5G application. Compared with ideal uncorrelated antennas in an 8 × 8 MIMO system, the 5G antenna module has shown good ergodic channel capacity of ~40 b/s/Hz, which is only 6 b/s/Hz lower than ideal case. This multi-mode hybrid antenna is fabricated, and typically, experimental results such as S-parameter, antenna efficiency, radiation pattern, and envelope correlation coefficient are presented.
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