A design of an ultra-wideband eight-port multiple-input multiple-output (MIMO) antenna array in a smartphone with an open-slot metal frame for fifth-generation (5G) communications is presented. Each element is fed by a microstrip line with a tuning stub, consisting of a U-slot on the ground plane and an open slot on the metal frame. Each slot element on the ground only occupies an area of 15 ×3 mm. The antenna array can operate in 3.3-6 GHz (S 11 < −6 dB) that is ultra-wide bandwidth for the future 5G communications. The antenna array is manufactured and measured. Measured antenna isolation is higher than 11 dB without any decoupling structures applied. Moreover, measured radiation patterns, antenna efficiencies, and envelop correlation coefficients are also given in this paper. High agreement between the measured and simulated results is obtained, which means that the proposed antenna is promising in engineering application. INDEX TERMS 5G communication, metal frame, MIMO antenna, smartphone, ultra-wideband.

A wideband 8-antenna Multiple-Input Multiple-Output (MIMO) array covering 3.3-7.1 GHz for Fifth-Generation (5G) sub-7 GHz and New Radio Unlicensed (NR-U) applications in metal-rimmed smartphones is presented in this paper. In this design, the open slot loaded metal rim is directly fed by microstrip line. Hybrid Inverted-F Antenna (IFA) and slot modes are generated. Utilizing impedance matching and reactance loading, the two modes are moved and combined, so as to achieve size reduction and wideband coverage. The size of the ground slot (clearance) is only 12.4 mm × 1.5 mm (0.136 λ×0.016 λ at 3.3 GHz). The proposed MIMO antenna array is fabricated and measured. Results show that in the desired wide frequency band, the proposed design can achieve desirable antenna performances, including isolation >11 dB, total efficiency >47%, and calculated Envelope Correlation Coefficient (ECC) <0.09. Besides, antenna gain, radiation pattern and calculated ergodic channel capacity are demonstrated as well. The proposed metal-rim-integrated MIMO antenna array features small size, simple structure and wide bandwidth. It can be a good application-oriented design in next-generation 5G mobile communication.

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Micro thin film thermocouples (TFTCs) can provide measurements with high spatial and temporal resolution. If these micro sensors can be embedded in metals, tremendous benefits can be achieved for real industrial applications. In this study, a novel batch microfabrication technique, based on the thin film transfer technique and wafer-scale embedding process, was developed to fabricate and embed thin film sensors into an electroplated nickel structure. To investigate the performance of metal embedded TFTCs and the effect of size on their temporal and spatial resolution, TFTCs with different junction sizes and film thicknesses were fabricated and characterized. The dynamic response time of the sensor on a metal substrate, as measured by the pulsed laser heating method, indicates that TFTCs have a significantly faster response than conventional thermocouples. The static response of the embedded sensor is found to be linear with temperatures up to 900 °C while the thermal sensitivity of the embedded TFTCs (film minimal thickness > 100 nm) matched well with that of a standard K-type thermocouple. As the junction size is incremented, no significant differences in the thermal sensitivity were observed, nevertheless the temporal resolution reduced. Thinner film thickness results in a faster response but reduced thermal sensitivity for embedded TFTCs.

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Biocoordination polymer (BCP) nanowires are successfully constructed through self-assembly of chiral cysteine amino acids and Cd cations in solution. The varied chirality of cysteine is explored to demonstrate the difference of BCP nanowires in both morphology and structure. More interestingly and surprisingly, the electrical property measurement reveals that, although all Cd(II)/cysteine BCP nanowires behave as semiconductors, the conductivity of the Cd(II)/dl-cysteine nanowires is 4 times higher than that of the Cd(II)/l-cysteine or Cd(II)/d-cysteine ones. The origin of such chirality-discriminated characteristics registered in BCP nanowires is further elucidated by theoretical calculation. These findings demonstrate that the morphology, structure, and property of BCP nanostructures could be tuned by the chirality of the bridging ligands, which will shed light on the comprehension of chirality transcription as well as construction of chirality-regulated functional materials.

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As a typical layered inorganic analogue of graphene, molybdenum disulfide (MoS2) has gained intensive attention and become a research hotspot due to its unique two dimensional nanostructure and excellent properties.