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Summary: In this communication, a dual port printed multi‐input and multi‐output (MIMO) antenna with high isolation of dimension 12 × 8.5 × 0.8 mm3 is designed, analyzed, and investigated for 28‐GHz 5G mm‐wave applications. The metasurface layer is suspended over the MIMO antenna to convert the linearly polarized (LP) wave to a circularly polarized (CP) wave. The unit cell of the metasurface consists of a square‐shaped conducting strip with one side of diagonal points interconnected. The conducting strip and rectangular gap between the strips etched on the substrate are capable of generating the π/2 phase shifted electric field components (Ex and Ey) resulting in polarization conversion from LP to CP. The machine learning concept is used to characterize the dimensional configuration of the antenna to achieve the optimum throughput. The MIMO diversity performance parameters and antenna essential results are validated by the measured counterparts. [ABSTRACT FROM AUTHOR]

Summary: A novel antenna system that utilizes multiple‐input and multiple‐output (MIMO) technology to suit the requirements of 5G applications is proposed in this article. The antenna has a wide operating bandwidth and high isolation in n257/n258/n261 5G bands. The suggested arc‐shaped MIMO antenna is composed of four similar patch units with modified ground planes arranged in a four‐port configuration and is made on a Rogers RT/duroid 5880 substrate, which measures 31.891 × 37.5885 × 0.508 mm3. The prototype of the suggested MIMO antenna is realized to confirm the obtained simulated results and validate the proposed design. The four‐port MIMO antenna features a broad frequency range of 7.3 GHz from 21.8 to 29.1 GHz, a peak gain of 5.76 dBi at 29 GHz, and a good isolation less than −18 dB. The proposed antenna's MIMO performance is evaluated by analyzing several diversity parameters. The findings of the evaluation demonstrate an envelope correlation coefficient (ECC) value of less than 0.001, a diversity gain (DG) value exceeding 9.995 dB, and an average mean effective gain (MEG) of −3 dB within the operational frequency band. The suggested MIMO antenna's compact size and impressive performance make it a suitable choice for intended n257/n258/n261 5G NR networks. [ABSTRACT FROM AUTHOR]

Summary This article analyses a substrate integrated waveguide (SIW) fractal koch surface (FKS) slot antenna performance for Ka‐band applications. This FKS slot shape is obtained by modifying the conventional rectangular slot with the first iteration of the FKS method. The resultant FKS slot behaves as a radiator in the provided space. A single‐ and two‐element FKS slotted SIW antenna characteristics are analysed on a 20 mil thick RT/Duroid 5880 substrate and compared with the conventional rectangular slot. The proposed antenna with dimensions 15×5×0.508$$ 15\times 5\times 0.508 $$ mm3 achieves an impedance bandwidth from 27.4 to 32.1 GHz with a fractional bandwidth of 15.79% and achieves a gain of 8.3 dBi in broadside direction by improving space filling factor in SIW structure. The prototype of the SIW‐fed FKS slotted antenna array measurement results is satisfactory with the simulation results. [ABSTRACT FROM AUTHOR]

Summary: This article communicates a novel compact four‐element orthogonal cavity‐backed antenna for 5G applications with enhanced isolation. The proposed dumbbell‐shaped substrate integrated waveguide–multiple input/multiple output (SIW‐MIMO) antenna resonate at 5.25 GHz (sub‐6 GHz) based on vias and resonate at 27 GHz (mm‐wave) with copper filling vias using FR‐4 substrate. Both prototypes are separately designed, fabricated, and tested using same dimension (40 mm × 40 mm × 1.6 mm) as well as same radiating structure. Moreover, SIW MIMO antenna design performances are compared between FR‐4 and Rogers RT/Duroid substrate. Deployment of SIW technique in MIMO antenna minimizes the antenna footprint and mutual coupling without involving any decoupling structure. The antenna simulation characteristics of both operating bands are compared and validated with the measurement results. Furthermore, the MIMO diversity parameters are examined. [ABSTRACT FROM AUTHOR]

Summary: This research suggests a compact uniplanar multiple‐input multiple‐output (MIMO) with four ports for n79/n46/millimeter‐wave (mm‐wave) applications. The size of the quad MIMO is only 30 × 30 × 0.8 mm3. MIMO system consists of four identical Z‐shaped radiators and common ground on the same plane and no decoupling structures are used for isolation. The system covers the bandwidth of 1.9 GHz (4.4–6.3 GHz) with a mid‐frequency of 5.6 GHz and also covers the high‐band frequencies ranging from 18 to 30 GHz with a bandwidth of 12 GHz. The suggested quad MIMO is fabricated on an FR‐4 board, and the measured outcomes are well in line with the simulated results. An isolation value of −11 dB has been achieved for mid‐band frequency and −24 dB has been attained for mm‐wave bands. Through the value of DG = 10 dB, ECC < 0.07, TARC < −3 dB, MEG < −5 dB, and the ratio of MEG = 1 dB, uniplanar quad MIMO shows acceptable MIMO diversity performance. The entire system was evaluated for the users' hand specific absorption rate (SAR) impacts and is within the limits. After the complete analysis of the miniature quad MIMO antenna, an 8‐port, and a 16‐port uniplanar MIMO are simulated for smartphone‐sized dielectric substrates and the performances were examined. The suggested MIMO system provides an efficient single‐layer MIMO antenna to 5G smartphones with high bandwidth and low SAR. The proposed quad MIMO systems are suitable for both the sub‐6 GHz band and the mm‐wave band. [ABSTRACT FROM AUTHOR]

The design of short-range high-speed wireless networks for the 60 GHz band requires consideration of factors from a wide range of disciplines. Key system choices that make significant differences to the final cost and performance include the type of antennas, multiple access strategy and channel coding. In this paper we assume a coded orthogonal frequency division multiplexing (OFDM) system providing high-speed communications between low-cost terminals over indoor 60 GHz channels that are frequently non-line-of-sight. Under constraints of low transmit power and high path attenuation, we consider two practical options for using multiple low-cost ‘bond-wire’ antennas, compared with ideal monopole antennas at each terminal. For specified multiple access and channel coding schemes, we show that a sectorized strategy based on simple 2 element phased arrays can provide substantial benefits in system performance and flexibility. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]