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Summary: This article presents a quad element wideband multiple‐input multiple‐output (MIMO) antenna consisting of human face‐shaped patch radiators with defected ground structure (DGS) having rectangular split ring resonator (RSRR) in ground surface. The measured bandwidth of the proposed MIMO antenna is 3.0–6.5 GHz, and the isolation between the ports is more than 16 dB. Additionally, simulated diversity characteristics like the channel capacity loss (CCL), channel capacity (CC), total active reflection coefficient (TARC), mean effective gain (MEG), and envelope correlation coefficient (ECC) are investigated with the measured value and observed to be within the acceptable ranges over the operating frequency band. The suggested antenna can be used in the wireless local area network (WLAN) (i.e., 4.9–5.725 GHz), wireless fidelity (Wi‐Fi) (i.e., 5.15–5.85 GHz), and 5G under 6 GHz (3.3–5.0 GHz) frequency ranges. [ABSTRACT FROM AUTHOR]

In this paper, a planar of small size Tapered slot Vivaldi antenna for mm‐Wave 5G application is proposed. The main goal can be presented by designing of a small size antenna with good performance antenna for mmWave and massive MIMO applications. The suggested antenna structure is portrayed by a size of 6.4 × 6 × 0.254 mm3 printed on a dielectric substrate (Roger/RT Duroid −5880) with εr = 2.2, and tanδ = 0.0009. The antenna displayed a small size and good performance with an impedance bandwidth equals 17.9 GHz ranging from 22.1 GHz to 40 GHz with the value of S11<−10 dB, which covers all mm‐Wave frequency bands. The antenna gain is found fluctuating from 6.2 dB up to 7.1 dB in the whole band, which the maximum gain value is found at 22.1 GHz. The radiation of the antenna is found the end‐fire type. The HFSS software package was used to design and simulate the proposed antenna structure. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Summary: A novel pattern reconfigurable antenna is proposed in this letter. The overall dimension of the antenna is 11 × 11 × 0.787 mm. The proposed antenna is fabricated on Rogers RO4003C substrate. The antenna has two meandered monopoles and two straight monopoles. Two PIN diodes are connected between meandered monopoles and feed. The proposed design has three states of switching, that is, ON‐ON, ON‐OFF, and OFF‐ON. The antenna radiates from 18.5 to 26.25 GHz band with more than 5 GHz (−10 dB) bandwidth for all states. The proposed geometry exhibits 270° radiation beamwidth with 45° and 135° directions for ON‐OFF and OFF‐ON state, respectively. [ABSTRACT FROM AUTHOR]

Summary: A four‐element hexa‐band inverted U‐shaped merged stubs miniaturized Multiple‐Input Multiple‐Output (MIMO) radiator, operating in 2.10–2.17 GHz for 3G (2.17 GHz) band, 2.52–2.60 GHz for 4G (2.5 GHz) band, 3.31–3.46 GHz for 5G (3.4 GHz [n77 and n78]) bands, 3.66–3.72 GHz for 5G (3.7 GHz [n77 and n78]) bands, 4.53–4.62 GHz for 5G (4.5 GHz [n79]) band, and 5.15–6.02 GHz for 5.5 GHz WLAN bands, is developed. The radiator and ground planes comprise of multiple inverted U‐shaped stubs and slots to form the proposed configuration having overall compact dimensions of 62 × 62 × 1.6 mm3. The peak gain and radiation efficiency of the antenna are found to be 1.31 dBi and 77.48% at 2.17 GHz, 0.98 dBi and 63.3% at 2.55 GHz, 2.9 dBi and 71.13% at 3.38GHz, 1.6 dBi and 66.68% at 3.68 GHz, 2.58 dBi and 77% at 4.57 GHz, and 3.27 dBi and 68.68% at 5.52GHz. The arrangement of four antenna elements is orthogonal (rotationally symmetric) to minimize the mutual coupling, and hence, a minimum isolation of more than 15 dB is noted between all the antenna ports. Furthermore, Envelope Correlation‐Coefficient (ECC) in desired bands is lower than 0.012. Channel Capacity‐Loss (CCL) and Diversity‐Gain (DG) are also good with 0.015 bits/s/Hz and 9.96 dB, respectively. The fabricated structure measurement results agree well with simulation outcomes. These facts result that the proposed MIMO structure is a promising module for the usage in WLAN, 4G, and 5G band applications. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a compact (20 × 20 × 1.59 mm3), (0.34λg × 0.34λg × 0.01λg at 2.4 GHz) triple band monopole antenna for Internet of Things (IoT) applications. The geometry of the antenna consists of (i) U‐shape monopole with feed line, (ii) stubs, and (iii) modified ground to achieve three independent operating bands ranging from (i) 2.4–2.48 GHz for industrial, scientific, and medical (ISM)/3G; (ii) 3.4–3.6 GHz for 4G/5G; and (iii) 5.725–5.825 GHz for 5.8G Wi‐Fi/extended 5G. Various parameters, input impedance, and current distribution of the proposed structure are carried out to investigate the effects of stub, ground plane and analyze the radiation. The measured result covers the three individual bands in range of 2.38–2.48 GHz, 3.41–3.61 GHz, and 5.76–6.04 GHz, respectively, and exhibits stable omnidirectional radiation patterns, acceptable antenna gain, and efficiency in the operating bands. The experimental result of the fabricated antenna closely matches with the simulated result. Therefore, satisfactory result ensures its ability to work for 3G/4G/5G/extended 5G IoT portable applications. [ABSTRACT FROM AUTHOR]

Summary: The rapid growth in wireless communication technology and the proliferation of multimedia applications, specifically Voice over Wireless Fidelity (VoWiFi), necessitate the exploration of innovative techniques for improving network performance and quality‐of‐service (QoS). This research paper presents an innovative approach to enhance VoWiFi cell capacity using aggregate medium access control protocol data unit (A‐MPDU) frame aggregation for variable bit rate (VBR) traffic. In this research article, we investigated the effect that the retransmission of voice packets has on the cell capacity of a wireless local area network (WLAN) standard that provides VoWiFi service while taking into account the A‐MPDU approach. When taking into consideration the constant bit rate (CBR) and VBR traffics, we compared the results obtained using WiFi 6 (i.e., IEEE 802.11ax) with older WLAN standards such as IEEE 802.11b/g/n/ac. [ABSTRACT FROM AUTHOR]

Summary: The past decade has brought prolific developments to power systems that range from large‐scale renewable integration to digital twins. Modern power systems consist of highly variable generation clusters. Hence, monitoring and prediction of power generation has become a vital part of today's power systems. On the other hand, detailed real‐time information of power usage is also a key parameter for the control algorithms used for the demand side management. With this information flow, power systems become smart grids which offer improved service and enable many advanced operations. In this regard, the home area network (HAN), which collects the power consumption/generation of household devices, plays a key role. So far, a number of technologies such as ZigBee, Z‐Wave, and Power Line Communication (PLC) have been considered for the HAN. Yet, widely used wireless local area network (WLAN) technology, Wi‐Fi, was not identified as a prominent candidate due to the limitations in its latency and reliability. However, with the introduction of the IEEE 802.11ax standard, Wi‐Fi 6 was developed, and it demonstrates guaranteed latency and reliability for its users. Thus, with its widespread deployment in households, Wi‐Fi is becoming a natural candidate for HAN. In this article, we present a comprehensive HAN protocol based on Wi‐Fi 6 which can achieve guaranteed latency and reliability for HAN users. The results show that when an efficient resource allocation mechanism is in place, using Wi‐Fi for HAN does not adversely affect the other Wi‐Fi users in the normal WLAN. [ABSTRACT FROM AUTHOR]

Summary: A new structure of an asymmetrical switched‐capacitor‐based multilevel inverter topology is proposed. The circuit is capable of generating 17‐level boosted output utilizing 11 switches and two DC sources in the ratio of 1:2, having a voltage gain of 2.6 times the input voltage. The boosting capacitors were properly charge‐discharged during one complete cycle without requiring any complex control circuit for voltage balancing. The simulation model of the proposed circuit is developed in MATLAB, and the performance of the circuit is experimentally validated. The thermal modeling using PLECS software for power loss evolution is performed, and the maximum efficiency of 97.70% is achieved by implanting a low switching frequency scheme. The comparison with the other similar topologies shows the proposed topology is better than the other compared topologies in many parameters. The boosted output voltage utilizing reduced components makes the proposed topology feasible for various applications, including solar PV system. [ABSTRACT FROM AUTHOR]

Conventionally, both electrically larger (EL) arrays and sparse arrays offer the advantage of element number reduction but disadvantage of high sidelobe levels. A new scheme of planar EL sparse array antenna based on a genetic algorithm (GA) to achieve low sidelobe with element number reduction is proposed. To begin with, EL sparse array antenna optimisation models based on GA for both linear and planar arrays are analysed. Then, an EL slot antenna element based on a 3 × 3 substrate integrated waveguide cavity is designed. An 8‐element linear EL sparse array antenna is designed and compared with a uniform array antenna, demonstrating a reduction in the maximum sidelobe level (MSLL) by nearly 4.6 dB. After that, a 4 × 8 element planar EL sparse array antenna is fabricated and measured. Compared to an 8 × 16 element planar EL uniform array antenna, the number of antenna elements is reduced by 75%, while the MSLL is reduced by approximately 3 dB. The measured −10 dB impedance bandwidth ranges from 25.3 to 27.8 GHz. At the central frequency, the radiation pattern achieves a peak gain of 29.6 dBi, exhibiting low sidelobe levels below −15.0 dB. [ABSTRACT FROM AUTHOR]

Reflectarray (RA) antennas are gaining recognition as a high‐performance alternative for antenna design. They combine the functionalities of standard parabolic reflectors and phased array antennas without a feed network. However, the design of RA models requires a model that exhibits exceptional performance while meeting contradictory requirements such as size and operation band. An effective and computationally efficient approach is to employ a rapid and precise unit element model for the design of reflective antennas. Artificial intelligence (AI) regression techniques have been developed to predict electromagnetic behavior efficiently and accurately in microwave device design. A cross‐shaped 3D printable RA was examined as a case study, and a design‐ready surrogate model was developed with a mean absolute error of approximately 5° using only 800 data samples. The method can be considered a feasible substitute for current surrogate‐assisted RA design techniques due to its computational efficacy and dependability. [ABSTRACT FROM AUTHOR]

This paper presents a novel circular fractal ring monopole antenna for ultra‐wideband (UWB) hardware with dual band‐notched properties. The proposed antenna consists of four crescent‐shaped nested rings, a tapered feeding line at the front of the dielectric material, and a semicircular ground plane on the backside. In this design, the nested rings are used both as a radiation element and a band rejection element. The proposed antenna has a bandwidth of 9.03 GHz, which works efficiently in the range of 2.63 GHz–11.66 GHz with the dual notched bands of Worldwide Interoperability for Microwave Access (WiMAX) at 3.15 GHz–3.66 GHz and wireless local area network (WLAN) at 4.9 GHz–5.9 GHz, respectively. The antenna has a compact size of 20 mm × 30 mm × 1 mm (0.177 × 0.265 × 0.0084 λ0) and is implemented using a flame‐retardant type 4 (FR4) material. It has a maximum gain of approximately 4 dB in its operating range, and experimental results support the simulation predictions with high accuracy. The findings of this study imply that the designed antenna can be utilized in UWB applications. [ABSTRACT FROM AUTHOR]

Summary: A small size, dual‐band and dual‐sense monopole antenna is proposed to improve the axial ratio bandwidth (ARBW). The proposed antenna is considered on a low‐cost lossy FR4 substrate with parasitic strips (PSs) and partial ground plane of half guided wavelength dimensions. The dimension of the antenna in terms of wavelength is 0.27λ0×0.29λ0×0.02λ0, where λ0 is the wavelength at the lowest resonant frequency. The circularly polarized (CP) mode is created for strong orthogonal electric fields EX and EY. The obtained phase difference (PD) between two electric fields EX and EY is varied from 86° to 96° under ARBW. The achieved ARBW is 3.68–3.8 GHz, 4.84–12.58 GHz, and impedance bandwidth (IBW) is 3.51–3.82 GHz and 4.28–15 GHz. The applications of the proposed antenna are International Telecommunication Union (ITU) for 5G, C‐band IEEE 802.11a wireless local area network (WLAN) at 5 GHz (5.15–5.825 GHz) and X‐band wireless systems. [ABSTRACT FROM AUTHOR]

This paper presents the design and prototype development of a compact frequency‐selective surface (FSS) for shielding WLAN signals. The FSS unit‐cell geometry is evolved by modifying the arms of the conventional crossed dipole element. The footprint of the unit cell is only 6 mm × 6 mm × 1.6 mm. The proposed FSS offers stop band characteristics at 5 GHz for both transverse electric (TE) and transverse magnetic (TM) modes. In addition, the FSS offers angular stability up to 60°. A prototype of the proposed FSS is fabricated and measured to validate its simulations. Measured bandwidth of the stop band is 410 MHz, referenced at −20 dB for both TE and TM modes. Equivalent circuit model of the FSS is derived and the results are compared with the simulations. [ABSTRACT FROM AUTHOR]

A novel‐shaped dual‐polarized low‐profile multiple‐input multiple‐output (MIMO) antenna with high isolation is proposed for 5G/WLAN application. An 8‐element MIMO antenna design comprises two unique planar radiators (chamfer, circular). Each radiator has dual feed and dual polarization characteristics. The prototype is fabricated with an FR‐4 dielectric substrate. A decoupling structure maintains desirable isolation for self‐isolated elements (≤ $\le $−12 dB) using substrate integrated waveguide stubs between inter‐ports and high isolation among the adjacent radiating elements (≤ $\le $−15 dB). The simulation was performed by using CST microwave studio. The simulated results of the proposed MIMO antenna are compared with the measurement results. Furthermore, ECC and DG are investigated. [ABSTRACT FROM AUTHOR]

This work investigates a switchable 4G/5G dual-antenna system designed for laptops. The dual open-slot antenna structure is straightforward, with a slot width of only 2 mm. Each individual antenna features two different feed sections located in two separate regions between the slots. Port 1 is a direct-feeding design with 3.6 pF chip capacitance, while Port 2 is only a direct-feeding design. When Port 1 is excited and Port 2 is terminated to 50-Ω, the antenna is functional in long-term evolution (LTE) low-band (617-960 MHz) and 5G sub-6 GHz band (3300-5000 MHz). On the other hand, when Port 2 is excited and Port 1 is terminated to 50-Ω, the antenna is functional in the LTE medium/high bands between 1710 and 2690 MHz. The measured isolation consistently exceeded 30 dB, and the efficiency remained above 48% across the entire frequency range. The calculated envelope correlation coefficients derived from the complex E-field radiation pattern measurements were consistently below 0.02. These findings indicate that the system is exceptionally well-suited for applications characterised by integrated metallic environments and a high display-to-body ratio. [ABSTRACT FROM AUTHOR]

This letter proposes a broadband mono‐cone antenna with a shorted parasitic ring and parasitic metal pillars. Four parasitic metal pillars expand the high‐frequency operation band, while a shorted parasitic ring increases the current flow path and expands the low‐frequency operation band. A 148.3% impedance bandwidth for VSWR ≤ 2 from 0.831 to 5.6 GHz is attained. The antenna has stable radiation performance across the entire operation spectrum. The simulated and measured results show a good agreement. It is exceptionally compatible with GSM900, DCS1800, PCS1900, UMTS, IMT2000, WiBro, WiMAX2350/3500, LPWAN, wireless LAN (IEEE 802.11b), and a portion of the WLAN/Wi‐Fi frequency spectrum. Indoor applications such as wireless energy collection, partial discharge detection, and so on are possible for the proposed antenna. [ABSTRACT FROM AUTHOR]

Optically transparent dual‐band frequency‐selective surfaces (FSSs) are promising candidates to address the specific design challenges of the Internet of Things. This paper demonstrates their potential by discussing different configurations of the two single‐layer FSS designs on an innovative optically transparent polyvinyl chloride surface material. First, FSS cells consist of two cross dipoles placed forming angles of ±45∘ $\pm 4{5}^{\circ }$, where each rotated dipole structure parallel to the other. Then, in the second design, each one of the two cells is mirrored to enable polarization control for each band. As a proof‐of‐concept, five prototypes of each design having a unit cell size of 0.43λ0×0.43λ0 $0.43{\lambda }_{0}\times 0.43{\lambda }_{0}$ are fabricated through a combination of cost‐effective printing and shearing. The manufactured prototypes yield more than 93% transparency and robust dual‐band performance. Moreover, more than 20 and 40 dB isolation for lower‐ and upper‐frequency bands are achieved from the fabricated prototypes. High‐transparency, cost‐effectiveness, and robust high performance in terms of suppression make both structures suitable for sub‐6‐GHz fifth generation applications. [ABSTRACT FROM AUTHOR]

Securing internal wireless communication of a corporate network from external eavesdropping requires electromagnetic (EM) shielding of the whole building, which may also block useful communication bands, such as mobile phone, radio, security, and television networks. Frequency selective surfaces provide selective spatial filtering of EM signals. A dual concentric modified square loop of unit‐cell dimension 26.16×26.16 mm2 $26.16\times 26.16 {\mathrm{mm}}^{2}$, fabricated on a window blinds material with dielectric constant 1.63 is presented for shielding indoor wireless network. The design resonates at WiFi and Bluetooth frequencies of 2.4 and 5 GHz and offers a measured suppression of at least −45 dB at both the frequency bands. Simulation and experimental results have been presented which exhibit stable and polarization insensitive responses in both, transverse electric and transverse magnetic modes, as well as angular stability for oblique incident angles up to 60°. The proposed Frequency Selective Window Blinds provide on‐demand, passive EM shielding and are easy to develop, install, and use. [ABSTRACT FROM AUTHOR]

In this letter, we present a new frequency selective surface (FSS) for shielding 2.4–2.5 and 4.98–5.825 GHz wireless local area network (WLAN) bands. This FSS structure is based on the traditional Sierpinski octagon and we improve it. Compared with the traditional structure, the improved one has a smaller element size and better angular stability. The design is realized on float glass with a relative permittivity (εr ${\varepsilon }_{r}$) of 8, and the unit cell size is 0.1152λ0 × 0.1152λ0 (λ0 is the free space wavelength at the first resonant frequency). Wide rejection bandwidths (−10 dB) of 910 and 1630 MHz are obtained at 2.4–2.5 and 4.98–5.825 GHz, respectively. The surface current distribution and the equivalent circuit model are illustrated to explain the resonance behavior of the proposed FSS. Furthermore, this FSS exhibits stable frequency response to incident angles of 0°–80° under transverse electric and transverse magnetic polarizations. Finally, this FSS structure was fabricated and measured. The measured results demonstrate that this FSS structure has good performance in WLAN applications. [ABSTRACT FROM AUTHOR]

This paper presents the design of a novel dual‐band quasi‐Yagi antenna for on‐body communications. The proposed antenna is designed on 0.05 mm thin microwave laminate and is designed to cover the 2.45 and 3.5 GHz spectrum to meet the needs of on‐body Internet of Things networks. Microstrip to slot‐line transition is used for the excitation of the feeder element. The conventional feeder of the quai‐Yagi is replaced with F‐shaped radiators to obtain a dual‐band response. In addition, a pair of directors are used to enhance the antenna gain. The proposed quasi‐Yagi antenna is optimized using the spider monkey algorithm. The chosen algorithm is used to synthesize the dimensions of the dual‐band radiator and is preferred to obtain quick convergence, unlike the traditional optimization algorithms. The optimized planar quasi antenna offers 5% bandwidth in both operating bands with a measured gain of 5.7 and 5.8 dBi, respectively. The optimization time is also considerably reduced in comparison with traditional optimization algorithms. The simulated and optimized antenna is fabricated and tested. [ABSTRACT FROM AUTHOR]

A slotted microstrip patch antenna for fifth‐generation (5G) mobile applications is presented in this paper. The proposed antenna addresses the intrinsic narrow bandwidth of patch antennas by introducing rectangular slots in the form of a disjointed H‐slot to broaden the bandwidth. The patch design and the slots introduce two extra resonances to broaden the bandwidth of the antenna. An impedance bandwidth of 26.6% from 24.95 to 32.6 GHz was achieved. A measured peak gain of 9.44 dBi was also achieved with a minimum half‐power beamwidth of 36° over the entire bandwidth. The proposed slotted patch antenna is implemented on a 44.6 mm × 26.3 mm × 0.8 mm RT5880 Printed Circuit Board. [ABSTRACT FROM AUTHOR]

A multiband half‐mode substrate integrated waveguide (HMSIW) slotted antenna is developed for ISM/WiMAX/WLAN applications. HMSIW technique has been utilized to acquire antenna compactness. Two inverted L‐shaped slots of half wavelength are embedded onto a HMSIW rectangular cavity for attaining a hybrid mode (i.e., Half‐mode of TE110+ ${\mathrm{TE}}_{110}+\phantom{\rule{}{0ex}}$ Half‐mode of TE120 ${\mathrm{TE}}_{120}$), which induces a lower resonance at 2.4 GHz. An inverted L‐shaped slot is influenced to radiate hybrid mode at 2.4 GHz, while the innermost inverted L‐shaped slot radiates modified TE110 ${\mathrm{TE}}_{110}$ mode at 3.30 GHz. A multiband is obtained by amalgamation of hybrid mode (at 2.4 GHz), modified TE110 ${\text{TE}}_{110}$ mode (at 3.30 GHz) and modified TE120 ${\mathrm{TE}}_{120}$ mode (at 5.38 GHz). The radiating modes are elucidated by using mode theory methodology for ascertaining the resonance characteristics of the prototype antenna. The antenna parameters have been optimized by artificial neural network technique using MATLAB. The antenna geometry possesses a shrinkage size of 30 × 16 × 1.6 mm3, which has been designed on FR‐4 substrate. To vindicate the simulated consequence, the fabricated prototype has been tested. It contributes the fractional bandwidth of 6.4% (2.09−2.23 GHz) in the hybrid mode at 2.18 GHz, 9.03% (2.89−3.17 GHz) in the half cavity mode TE110 ${\mathrm{TE}}_{110}$ at 3.10 GHz and 9.96% (5.11−5.65 GHz) in the half cavity mode TE120 ${\mathrm{TE}}_{120}$ at 5.42 GHz, respectively, which is beneficial for ISM, WiMAX and WLAN band wireless applications. [ABSTRACT FROM AUTHOR]

This article presents a ±45° dual‐band dual‐polarized filtering antenna. The filtering antenna element is a dual‐polarized patch antenna that loads a parasitic patch with two rectangle slots to achieve compact multi‐array. Multi‐array consists of three 1×2 subarrays arranged, which are designed for 1.8/2.1 GHz FDD band applications. Very close‐arranged antennas exhibit radiation pattern invariance as well as in‐band radiation property. Radiation patterns are conformal with a compact subarray distance of 45 mm (0.29λ0), which is 56% smaller than that of the array using traditional filtering elements. Moreover, the total width is only 180 mm for three subarray‐composed antenna arrays. The average gain is 8.7 dBi with a low profile of 0.069λ0. The proposed array exhibits the filtering property of the subarrays with a very simple structure. [ABSTRACT FROM AUTHOR]

A two‐layered wideband single‐fed circularly polarised (CP) antenna is presented by the authors. A single‐fed corner‐truncated square patch with four identical rectangular matching branches acts as a bottom‐driven patch to generate CP radiation. To broaden the 3‐dB axial ratio (AR) bandwidth, a similar patch with a larger size is loaded atop the driven patch as a parasitic patch. The measured results show that the proposed CP antenna has a 17.9% impedance bandwidth from 2.13 to 2.55 GHz and an 11% 3‐dB AR bandwidth from 2.15 to 2.4 GHz, respectively. The measured total gain is 7.1 dBic. The results indicate that the proposed antenna is a good candidate for Wireless Local Area Network band applications. [ABSTRACT FROM AUTHOR]

Summary: In this paper, an equivalent circuit model‐based electrically small patch antenna is designed for sub‐6 GHz 5G application (3.5 GHz) using 50‐Ω microstrip line feed. The overall size of the proposed antenna is 0.33λ0 × 0.4λ0 × 0.019λ0 (28 × 34 × 1.6 mm3) at 3.50 GHz frequency. The proposed antenna has a tilted Y‐shape slot, two rectangular shape slots, and two rectangular shape notches in the radiating patch. The proposed antenna is resonating from 3.21 to 3.74 GHz covering the entire sub‐6 GHz 5G band (3.3–3.8 GHz). The impedance bandwidth (simulated) of the proposed antenna has been obtained 530 MHz resonating at 3.50 GHz frequency. The good return loss of −23.62 dB is also obtained at 3.50 GHz resonant frequency. The simulation results and geometry of the proposed antenna are validated with equivalent circuit model and experimental measurement of prototype antenna using vector network analyzer (VNA) and anechoic chamber. In the whole operating frequency range, the measured findings show reasonable agreement with the simulated ones. The measured impedance bandwidth of the proposed antenna has been obtained 480 MHz (3.21–3.69 GHz) resonating at 3.48 GHz frequency with a return loss of −21.61 dB, while the theoretical impedance bandwidth of the proposed antenna has been obtained 720 MHz (3.18–3.90 GHz) resonating at 3.58 GHz frequency with a return loss of −21.5 dB. The peak gain of 3.39 (simulated) and 3.2 dB (measured) is obtained at 3.50 GHz frequency. Moreover, the antenna shows 97% (simulated) and 95% (measured) efficiency at 3.50 GHz frequency. [ABSTRACT FROM AUTHOR]

Summary: This research describes the detailed analysis and design of the compact complex‐free structural metamaterial quad band radiating element applicable for Bluetooth, WiMAX, WLAN, and fixed‐satellite service. The radiating element designed is composed of an inner angle‐rotated circular Split Ring Resonator (SRR) placed within the outer square‐shaped SRR interlinked by a strip to design the multiband operational characteristics and is fed by a coplanar waveguide. Suggested radiating element is imprinted over the FR4 substrate material with the electrical dimension of 28 × 31.26 × 0.8 mm3. The initial outer‐closed square ring offers dual‐band operation by resonating at 2.8 and 8.5 GHz frequencies, and the incorporation of a circular SRR offers quad‐band operation. The unique negative permeability feature of the proposed Square and Circular Split Ring Resonator (SCSRR) structure is extracted, and its band characteristics are analyzed. Results obtained from the simulated radiating element are validated with the fabricated antenna. The measured E plane pattern resembles a numeric eight shape, and the H plane pattern is omnidirectional. Suggested SCSRR antenna offers a gain of above 3.2 dBi in all the operating bands. [ABSTRACT FROM AUTHOR]

This article presents the design steps of a planar circularly polarized (CP) bowtie‐shaped antenna for 2.4–2.5 GHz industry, science, and medicine band. Using these design steps, an antenna model is developed. The antenna design is extensively described, simulated, measured, and analyzed. The antenna is simulated using the HFSS software and produced by laser etching of copper on a low‐cost Taconic RF‐35 substrate. The presented method of this design is easy to fabricate and is tunable to different frequencies. The produced CP planar antenna has a size of 55 × 55 × 0.25 mm3, a measured axial ratio bandwidth ranging from 2.33 to 2.49 GHz, and a measured peak gain of 3.21 dBiC. The produced antenna is fully planar, compatible with the printing process and thus suitable for Internet of Things applications. [ABSTRACT FROM AUTHOR]

This paper investigates a wideband omnidirectional antenna that possesses 124.7% of fractional bandwidth. The antenna's two crescent‐shaped radiating patches and their ultrawideband matching structures are printed on two laminates that are crossly placed vertically over the ground plane. Simulation shows that the structure on a single laminate radiates an "8"‐shaped pattern on the horizontal plane. The cross formation of the two printed laminates generates an omnidirectional radiation pattern by superimposing two "8"‐shaped patterns perpendicularly. The proposed antenna is fabricated and measured for demonstration. The measured results agree well with the simulation, indicating the omnidirectional antenna works from 1.38 to 5.95 GHz with a return loss of −10 dB. Simulation and measurement also show the gain variation on the xoy plane is 2 dB in the band of interest, which is small if the ultrawide bandwidth is considered. The above features make the proposed antenna a promising candidate for applications in the digital cellular system (DCS1800), long‐term evolution (LTE2300/2600), wireless local area network (WLAN2400), and IEEE 802.11p. [ABSTRACT FROM AUTHOR]

To effectively support low‐latency e‐health applications, a novel artificial intelligence‐based wireless local area network (WLAN) channel access control scheme named intelligent hybrid channel access (IHCA) is proposed and studied. In the IHCA scheme, each beacon interval comprises multiple cycles, with each cycle containing a contention‐free period (CFP) and a contention period (CP). By adopting an artificial neural network (ANN) and utilizing its calculation outputs to (1) decide whether to poll a hub during the CFP and (2) determine the initial backoff count (IBC) of each hub, polling of empty hubs during CFP can be reduced, and collisions during CP can be relieved. The authors' simulation results show that the IHCA scheme can effectively reduce latency compared to the Hybrid coordination function Controlled Channel Access (HCCA) and the Request based Polling Access (RPA) reference designs. [ABSTRACT FROM AUTHOR]

In this letter, an ultra‐wideband (UWB) eight‐element multiple‐input multiple‐output (MIMO) antenna system with multi‐loop modes for fifth‐generation (5G) smartphones is presented. The antenna unit has a simple structure and is composed of an inverted U‐shaped feeding strip and an L‐shaped grounding radiation strip with a hollow out in the middle. Owing to the generation of two coupling loop modes, the working bandwidth of the proposed antenna unit covers 3.2−6.4 GHz. Besides, the simulated and measured results show that the isolation between any two antennas is better than 12.0 dB, and the total efficiency of each element is higher than 50%. Meanwhile, the measured radiation pattern, envelope correlation coefficients, channel capacity loss, mean effective gain, and diversity gain are also given in this letter. The above results demonstrate that the MIMO system has the advantages of simple structure, convenient manufacture, and superior performance. [ABSTRACT FROM AUTHOR]

The uniplanar compact, affordable, and unique slot‐based multiband frequency selective surface (FSS) of periodic cell size 0.14λc × 0.14λc (λc is wavelength at the initial stopband resonance) is presented in this article. The quadband FSS is analyzed using full‐wave simulation, circuit simulation (ECM), and experimental measurement where good agreement is attained. The FSS offers polarization independence with steady responses for all angular variations in the TE plane and up to 45° in the TM plane. The FSS offers dual stopbands at 2.75–4.15 and 9.45–12.48 GHz and dual passbands at 0.001–0.8 and 4.74–5.6 GHz that includes spectrum coverage of GSM, LTE, WLAN, ISM, WiMAX, and most part of X‐band communication. [ABSTRACT FROM AUTHOR]

Summary: A reconfigurable MIMO antenna for heterogeneous vehicular networks is reported in this paper. The frequency and bandwidth characteristics of the MIMO antenna can be reconfigured to meet multi‐standard and multi‐frequency requirements in automobiles. The antenna element evolved from an edge‐chamfered ultra‐wideband (UWB) antenna operating from 2.1 to >15 GHz. The bandwidth reconfiguration is achieved through the selection of excitation paths connecting the feed and radiator. The feedline selection is performed using PIN diodes, making the antenna operate in three distinct modes, namely, UWB mode (Mode 1: 2.1–>15 GHz), industrial, scientific and medical/Internet of Things (ISM/IoT) mode (Mode 2: 2.45 GHz), and wireless local area network (WLAN) mode (Mode 3: 5–6 GHz). The feed path corresponding to Mode 2 and Mode 3 is incorporated with a suitable filtering network to shape the frequency response of the antenna based on the user's requirements. Owing to the requirement of cognitive selection of frequency bands, the frequency tunability in Mode 2 is realized using varactor diodes. The varactor‐incorporated feed path reconfigures the center frequency between 2.45 and 3.5 GHz. The proposed MIMO antenna offers gain and total efficiency greater than 2.94 dBi and 76%, respectively. The prototype of the 4‐port MIMO antenna is being fabricated to test its functionality in real time. [ABSTRACT FROM AUTHOR]

A low profile four‐element multiple‐input multiple‐output (MIMO) array of printed dipole antenna (PDA) backed by second iteration of Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for broadband wireless communications. First, a suggested PDA with a pair of microstrip E‐shaped dipoles excited by an E‐shaped microstrip feedline is used to expand the bandwidth in the range of 5.47–6.92 GHz (S11 ≤ −10 dB). Then, the suggested 4 × 4 Giuseppe Peano fractal AMC reflector is loaded into the PDA to exhibit −10 dB measured impedance bandwidth from 4.21 to 7.06 GHz (50.61%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The proposed four‐element MIMO array loaded by 6 × 6 AMC reflector with diverse polarizations of elements introduces a low profile wideband structure. The measured results of four elements include the broad bandwidths from 4.3 to 7.05 GHz with enhanced gains (more than 8 dBi) and high efficiencies. The high isolations between the four elements with diverse polarizations are obtained larger than 26.5 dB and they reach 66 dB over the operating bandwidth for MIMO systems. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 51.33%, enhanced radiation efficiency up to 94%, and excellent impedance matching with uni‐directional radiation patterns. [ABSTRACT FROM AUTHOR]

Convolutional neural networks (CNN) have a strong feature extraction ability for images and present a high level of efficiency and accuracy in object detection and image recognition. When CNN is used to model microwave devices, the existing literature generally uses its size parameters as one-dimensional (1-D) input, which does not give full play to the image-processing ability of CNN. In order to make full use of the characteristics of CNN, this letter converts the 1-D input of microwave devices into the form of an image model, that is, the 1-D input is transformed into a two-dimensional (2-D) matrix composed of 0 and 1 as the input. The image model is combined with CNN, called image-based CNN (ICNN), which establishes a deep learning surrogate model between the physical parameters and electrical properties of microwave devices and improves the accuracy and generalization ability of the model. Taking the resonant frequency of the microstrip antenna as a simulation example, modelling was carried out by the proposed ICNN and compared with the mainstream machine learning methods. The results show that the proposed method has high convergence and fitting accuracy. [ABSTRACT FROM AUTHOR]

A low‐profile 16‐element printed dipole antenna (PDA) array backed by a planar artificial magnetic conductor (AMC) is introduced for multiple‐input multiple‐output (MIMO) wireless communications. The proposed 16‐element MIMO array loaded by a 13 × 13 AMC reflector with various polarized directions exhibits a low‐profile wideband structure, which includes the broad measured bandwidths from 4.25 to 7.25 GHz with increased gains (>8 dBi) and high efficiency. The high isolation between the 16 elements with diverse polarizations is larger than 27 dB and reaches 67 dB over the operating band for MIMO systems. The suggested PDA with a microstrip V‐shaped dipole excited by a V‐shaped microstrip feedline is used to expand the broad simulated band spanning 5.34–6.70 GHz (S11 ≤ −10 dB). Moreover, the suggested 13 × 13 planar fractal AMC reflector is loaded into the PDA array to exhibit a reflection coefficient, S11, of less than −10 dB across the band of 4.26–6.90 GHz for wireless local area network and worldwide interoperability for microwave access applications. The proposed design with AMC compared to the design without AMC exhibits a size reduction of 50.3%, increased gain up to 8.2 dBi, and excellent impedance matching with unidirectional radiation patterns. The novel AMC unit cell is realized based on the planar patch with inserted slots to operate at 6.10 GHz with an AMC band spanning 5.15–7.10 GHz (32%). Plain Language Summary: A low profile sixteen‐element multiple‐input multiple‐output (MIMO) array of printed dipole antenna backed by planar artificial magnetic conductor is introduced for broadband wireless communications. It shows an enhanced features such as high stable gains, efficiencies, bandwidth, reduced size and high isolation for diverse elements of MIMO array. Key Points: Wiced gain and isolationLow‐profile multiple‐input multiple‐output array with enhanced isolation between elements can be used for wireless systemsArtificial magnetic conductors as periodic structures have been applied in microstrip antennas to improve their radiation performance [ABSTRACT FROM AUTHOR]

Summary: This paper presents the design of a miniaturized broadband monopole antenna for 5G and Wireless Local Area Network (WLAN) applications in mobile handsets. The proposed monopole evolved from a rectangular geometry of size 12 × 5 mm. The slot and stub loading techniques are used to improve the impedance matching offered by the antenna. Furthermore, bandwidth broadening is achieved using lumped elements loaded onto the aperture of the antenna. The proposed miniaturized antenna exhibits a measured impedance bandwidth of 63.6% (3.0–5.8 GHz) covering the 5G spectrum allocations under sub‐6 GHz and the WLAN services. The antenna elements are replicated along the sides of the mock mobile handset PCB to study the functionality of the eight‐element MIMO antenna. The prototype MIMO antenna fabricated and tested in the laboratory offers a peak gain of 3 dBi and total efficiency greater than 72%. Owing to miniaturization, the spatial distribution of the antenna element provides a low envelope correlation (ECC) of less than 0.2 and good diversity gain (DG) greater than 7.8 dB. In addition, the mean effective gain (MEG), channel capacity loss (CCL), multiplexing efficiency (ME), and total active reflection coefficient (TARC) are evaluated and presented. The estimated MIMO metrics are within the desired range of operation and hence make the antenna suitable for a complex propagation environment. The prototype antenna is developed on a thin microwave laminate with low‐loss characteristics and tested under laboratory conditions. The outcomes indicate that the proposed eight‐element antenna can be applied to 5G MIMO communications. [ABSTRACT FROM AUTHOR]

A capacitive coupling dual‐band circular patch antenna for on‐/off‐body communications is proposed for 3.5 GHz world interoperability for microwave access band and 5.8 GHz industrial scientific medical band. The antenna has a compact structure with a single substrate made of polydimethylsiloxane which is flexible and easy to wear. To realise off‐body mode, the antenna adopted bias feeding. The on‐body mode is achieved by symmetrically loading four shorting vias on the edge of the patch to stimulate TM41 mode, which tends to bring a high gain of the antenna. The measured operating bandwidths of the antenna for off‐body and on‐body modes are 120 MHz (3.45–3.57 GHz) and 360 MHz (5.54–5.90 GHz) respectively. The peak gains are 5.99 dBi for off‐body mode and 5.46 dBi for on‐body mode. Moreover, the antenna displays robust performances when it is bended or closed to human bodies. Meanwhile, low specific absorption rate values are proving that the antenna is safe to wear on human bodies. [ABSTRACT FROM AUTHOR]

In this letter, a single‐layer differential‐fed dual‐band filtering antenna for wireless local area network application is proposed. The proposed antenna consists of a square patch, and two pairs of stepped impedance resonators (SIRs). The lower operating passband is realized by exciting the square patch with a pair of differential ports. Then, a pair of SIRs is connected with the radiating edge of the square patch to introduce another resonance, thus forming the upper passband. And a radiation null is simultaneously produced to enhance the frequency selectivity between the two passbands. Moreover, another pair of SIRs is utilized to connect with the nonradiating edge of the square patch, which generates an additional high‐frequency in‐band resonance and a radiation null to further improve the bandwidth and frequency selectivity of upper passband. The developed prototype was fabricated and measured to verify the design concept. The measured results are in good agreement with the simulated ones, demonstrating that it exhibits −10 dB fractional impedance bandwidths of 3.68% and 7.35%, maximum realized gains at boresight direction of 5.5 and 8.7 dBi, and cross‐polarization levels smaller than −30 dB, in lower and upper passbands, respectively. [ABSTRACT FROM AUTHOR]

In this letter, a cavity‐backed annular slot antenna with a reconfigurable dual‐linear polarization of ∓45° employing two PIN diodes for wireless internet of things (IoT) applications was proposed to address issues such as bulky size, circuit complexity, and structural stability. The front‐to‐back ratio and gain enhancements of the proposed antenna with an overall size of 0.44 λ0 × 0.44 λ0 × 0.17 λ0 at 2.545 GHz were designed and accomplished utilizing a cavity‐backed reflector. The impedance bandwidth based on the 10 dB return loss and the peak gain of the proposed antenna are approximately 18.8% (2.26–2.73 GHz) and 7.42 dBi, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a simple and compact monopole antenna with a high bandwidth ratio (BDR) of around is investigated for super wideband (SWB) applications. Using an F4B substrate with a dielectric constant of 2.65, loss tangent of 0.002, and connecting it to a triangular tapered 50‐Ohm line, the suggested antenna achieves its performance objectives. The proposed antenna has an electrical dimension of 0.14λ × 0.22λ and spans the SWB frequency range of 2.89–60 GHz with a 181.5% fractional bandwidth and reflection coefficient S11 < −10 dB. It has been revealed that the results of both experiments and simulations are remarkably similar to one another in terms of their conclusions. In comparison to other SWB antennas, the suggested antenna has a greater BDR, a larger bandwidth, and a more compact size. Apart from that, the antenna has good gain and good radiation characteristics over the whole operational frequency range. [ABSTRACT FROM AUTHOR]

With the rapid development of electromagnetic (EM) wave manipulation technique, programmable metasurfaces with real‐time EM responses (e.g., phase, amplitude) have emerged as a new type of wireless communication transmitter, which has the advantages of simple architecture and low cost. Here, it has been proposed a design strategy of dual‐band wireless communication system based on a spatial‐division‐assisted multi‐level amplitude‐programmable metasurface. The carrier frequency and modulation scheme of each physical channel can be independently designed by changing the external bias voltages and the spatial‐coding sequences applied onto the metasurface. As the proof‐of‐concept, experiments are conducted to prove the feasibility of the system in sub 6G communication band. Two pictures are successfully transmitted via high and low‐frequency channels using binary amplitude‐shift keying and 4 amplitude‐shift keying modulation schemes, respectively. [ABSTRACT FROM AUTHOR]

Broadband millimeter Wave (mmWave) transmission at the 60 GHz band is a great prospect to meet the demanding high data rate requirements of future wireless personal area network (WPAN) and wireless local area network (WLAN) 5G networks. This paper proposes a single layer H‐plane sectoral horn mmWave antenna at 60 GHz using substrate integrated waveguide (SIW) technology for the future high‐speed short range WPAN and WLAN networks. The benefits of the proposed antenna are high gain, low cost, small size, and ease of integration with other planar circuits. The proposed SIW horn is constructed with RT/duroid 5880 substrate, which has a relative permittivity ε=2.2$ \epsilon = 2.2$ and loss tangent tan(δ)=0.002${\rm{tan}}(\delta) = 0.002$ with a thickness of 0.508 mm. The novelty of this work is; a wider bandwidth is achieved by adding striplines at the horn aperture to match the antenna with air and to increase the antenna operating bandwidth. In addition, the antenna gain is improved by adding a dielectric lens with the striplines at the radiating end. During these steps, the antenna parameters are tuned and optimized to achieve the best results as compared to related previous studies. The proposed antenna's performance is analyzed in terms of gain, return loss (S11) and radiation pattern at a frequency of 60 GHz. Simulation results are carried out by using industry standard software, Computer Simulation Technology (CST) microwave studio. The designed antenna achieves a peak gain of 13 dB and impedance bandwidth when S11<−10dB$S11 < - 10{\rm{\ dB}}$, 8.6 GHz (13.688%) for the reflection coefficient of −38dB$ - 38{\rm{\ dB}}$. The results show that the proposed antenna achieves stable tunable 60 GHz frequency performance, which makes it feasible to deploy in WLAN/WPAN operating in mmWave bands. [ABSTRACT FROM AUTHOR]

Summary: A small size neutralization line integrated flower‐shaped MIMO antenna is designed and analyzed for sub‐6 GHz type 5G NR frequency bands like n79 (4400–5000 MHz), n78 (3300–3800 MHz), n77 (3300–4200 MHz), and WLAN (5150–5825 MHz) applications. The novel approach of theory of characteristic mode analysis (TCMA) is introduced to provide physical insight of the designed structure and its characteristics behavior. Due to the suggested modifications in the geometry, the isolation among the patches is greatly increased. The overall miniaturized dimension of the MIMO antenna is 25 × 40 mm2. The edge‐edge spacing among the elements is 0.0233λ. The prototype antenna is fabricated and measured that shows good agreement compared with simulated results. The designed MIMO antenna without the presence of decoupling structure offers an isolation of 28 dB, gain of 3.6 dBi, and radiation efficiency of 69.7% at the resonant frequency. The proposed MIMO antenna covers a broad range of frequency band from 3.296 to 5.962 GHz with −10 dB impedance bandwidth of 2666 MHz and maintains a good isolation of greater than 50 dB for the entire operating band. The tested radiation efficiency and gain are 85.3% and 6.22 dBi at 3.5 GHz. Moreover, the diversity parameters of the neutralization line integrated MIMO antenna, that is, channel capacity loss (CCL) isolation, mean effective gain (MEG), total active reflection coefficient (TARC) diversity gain (DG), and envelope correlation coefficient (ECC), are analyzed and discussed in this article. [ABSTRACT FROM AUTHOR]

Summary: The most well‐known sort of remote Internet connection is wireless local area networks (WLANs) due to its unsophisticated operation and deployment. Subsequently, the quantity of gadgets getting to the Internet through WLANs, for example, PCs, cell phones, or wearables, is expanding radically at the equivalent time that applications' throughput necessities do. To provide wireless networks with supplementary spectral resources, the researchers are considering the aggregation of frequency spectrums in licensed, unlicensed, and shared access (SA) bands. Channel aggregation/channel bonding (CA/CB) techniques accumulate quite a few channels together as one channel for the purpose of achieving better bandwidth utilization. In this study, we focus on reliable CA/CB techniques in different wireless networks. CA/CB procedures are utilized for empowering higher information rates by transmitting in more extensive channels, accordingly expanding range proficiency with the assured secure channel for communication. We also discuss the spectral scarcity issues in today's wireless IoT network. This paper presents an extensive survey on CA/CB procedures and methods, issues and challenges, and open research areas related to IoT devices. We analyze the performance of channel CA/CB strategies in the different wireless networks too. [ABSTRACT FROM AUTHOR]

Summary: This work proposes an electrical compact triple‐bands antenna founded on a composite left‐/right‐handed approach. This structure contains a rectangular patch combined with two unit cells based on the metamaterial properties that are used to produce wide electrical lengths in miniature physical sizes. Thus, the presented antenna is designed with a lower resonant frequency and miniature physical dimensions compared to conventional antennas. The suggested antenna has been produced on top of the FR4 substrate having tan δ = 0.022, εr = 4.58, and a size of 28 × 16 × 1.6 mm3. This structure provides three bandwidths of (2.391–2.54 GHz), (3.42–3.56 GHz), and (5.02–11.40 GHz). Additionally, a multi‐input multioutput (MIMO) antenna is designed by placing two similar radiating patches in a perpendicular shape. Therefore, this design approach has been used to achieve an important isolation among ports and less than −30 dB at frequency bands. The results of radiation patterns, envelope correlation coefficient, diversity gain, and channel capacity loss are below to 0.06, 10 dB, and 0.4 b/s/Hz respectively, which confirms that the MIMO antenna is compatible with wireless MIMO devices. These antennas have been modeled and experimentally confirmed, and the results have proven that the suggested antennas are useable and can support multi‐standard wireless applications. [ABSTRACT FROM AUTHOR]

A dual‐wideband planar dipole antenna for WLAN and WiMAX applications is proposed. The antenna is mainly composed of a U‐shaped dipole which is fed by a parallel double transmission line. The U‐shaped dipole is employed to generate a wide lower band and a narrow higher band. To expand the higher band, two pairs of strips are used to symmetrically embed in the U‐shaped arms of the dipole. The tested results demonstrate that this antenna achieves two wide bandwidths about 53.6% (2.33–4.02 GHz) and 23.7% (5.04–6.45 GHz) at the higher and lower frequency band, which can satisfy the requirement of the whole 2.4/5.2/5.8‐GHz WLAN and 2.5/3.5/5.5‐GHz WiMAX bands. [ABSTRACT FROM AUTHOR]

In this article, we evaluate the first experience of computation offloading from drones to real fifth‐generation (5G) operator systems, including commercial and private carrier‐grade 5G networks. A follow‐me drone service was implemented as a representative testbed of remote video analytics. In this application, an image of a person from a drone camera is processed at the edge, and image tracking displacements are translated into positioning commands that are sent back to the drone, so that the drone keeps the camera focused on the person at all times. The application is characterised to identify the processing and communication contributions to service delay. Then, we evaluate the latency of the application in a real non standalone 5G operator network, a standalone carrier‐grade 5G private network, and, to compare these results with previous research, a Wi‐Fi wireless local area network. We considered both multi‐access edge computing (MEC) and cloud offloading scenarios. Onboard computing was also evaluated to assess the trade‐offs with task offloading. The results determine the network configurations that are feasible for the follow‐me application use case depending on the mobility of the end user, and to what extent MEC is advantageous over a state‐of‐the‐art cloud service. [ABSTRACT FROM AUTHOR]

A dual‐band printed dipole array antenna for a wireless local area network (WLAN) application is presented. A radiation element consists of four pairs of printed dipoles, and two radiation elements are collinearly arrayed. A broadside coupling microstrip line‐based two‐sectional impedance transformer is used to feed the radiation elements in parallel. The proposed dual‐band antenna is designed to cover the dual‐frequency bands (2.4–2.48 and 5.15–5.825 GHz) which are the lower‐ and upper‐frequency bands for WLAN operation. The experimental results support the proposed design theory and also exhibit the gain values of 3.89–4.88 and 5.79–7.18 dBi at the lower‐ and upper‐bands, respectively, maintaining the omnidirectional radiation pattern. The measured radiation efficiencies at each frequency points, 2.4, 5.2, and 5.5 GHz are 87.39%, 75.43%, 69.96%, and 73.07% $ \% $, respectively. In addition, for mass production, the effect from a low‐cost flexible coaxial cable, and polyethylene housing on the antenna performance is also investigated in this letter. [ABSTRACT FROM AUTHOR]

The presented article represents the rudimentary‐shaped effective 1 × 2 MIMO antenna structure. The five variation types in the ground region shape are analyzed. The structure's total dimensions are 40 × 36 × 1.6 mm3. For efficiently manufacturing, the low‐profile substrate FR4 is employed, and the reflectance response of a simulated and modelled design is compared. The placement of two T‐shaped slits in the ground area aids in achieving a wider bandwidth, multiband response, excellent Gain, and directivity. Overall, the PW:4 has a minimum reflectance coefficient of −34.54 dB, a broad bandwidth of 3.38 GHz, a peak gain of 13.02 dB, maximum narrow band isolation of 62 dB, and a maximum normalized directivity of 156°. The Envelop Correlation Coefficient, Channel Capacity Loss, Total Active Reflection Coefficient, and Diversity Gain for MIMO design are also examined. These findings indicate the provided design's behavior as per the standard requirements. [ABSTRACT FROM AUTHOR]

This article presents an electrically small asymmetric coplanar strip (ACS)‐fed metamaterial‐inspired antenna for multiband operation. The design employs a simple monopole, a set of rectangular split ring resonator (SRR), an inverted U‐shaped stub, and a rectangular complimentary split ring resonator (CSRR) in the ground plane to realize four operating bands. The antenna operates at 2.46, 5.8, 6.78, and 10.46 GHz with a bandwidth of 270 MHz, 340 MHz,180 MHz, and 1.16 GHz, respectively. The proposed structure has an electrical size of 0.186λ0×0.11λ0 $0.186{\lambda }_{0}\times 0.11{\lambda }_{0}$×0.013λ0 $\,\times \,0.013{\lambda }_{0}$ at 2.46 GHz. The experimental results are found to be in close proximity to the simulated ones. The presented electrically small antenna possesses a radian sphere (ka) of 0.68 and achieves an adequate gain of 2.37dBi with requisite radiation characteristics suitable for WLAN and satellite‐based applications. [ABSTRACT FROM AUTHOR]