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With multi-band rejection characteristics, a new low-profile antenna of size 34 × 34 mm2 is conferred in this article. It consists of quad identical monopole elements (originated orthogonally), contributing ultra-wideband characteristics in the system. The single unit of the proposed design consists of a modified spinning-top shape radiator (MSTSR), excited by a tapered microstrip line feed (TMLF) and semi-circular ground. An excellent bandwidth of 3–12.9 GHz (where S11 < − 10 dB) is obtained at each port. By inserting the structure of four spiral coils, a sharp notch ranging from 7.9 to 8.5 GHz is achieved to filter the X-band satellite communication uplink. In addition, a circular spiral slot in the radiator near the ground plane creates a stop band at 7.35–7.565 GHz band (satellite communication downlink band). Furthermore, symmetrical rectangular trapezoid resonators and inverted symmetrical rectangular trapezoid structures near the feed line are responsible for the elimination of interferences at 5.5 GHz lower WLAN and 3.5 GHz WiMAX respectively. The FR-4 substrate used for the UWB-MIMO design fabrication process and fabricated results are found in good match with the simulated results. Also, the design provides good performance metrics such as total active reflection coefficient, diversity gain, channel capacity loss, isolation, and envelope correlation coefficient. [ABSTRACT FROM AUTHOR]

This article introduces an innovative circular and compact ultra‐wideband (UWB) radiator designed specifically for 5G microwave applications. This antenna incorporates a “TU”-shaped ground plane on its reverse side, with strip lines feeding the circular element on the front side. Notably, the antenna exhibits impressive characteristics, including an outstanding impedance bandwidth of 107%, and an impressive return loss of -32 dB. Its operational frequency range spans from 2.4 GHz to 11 GHz, centered at 6.7 GHz. Extensive simulations were conducted using CST microwave studio software to validate its performance. The antenna’s physical dimensions are defined by a size of 0.12 λ × 0.08 λ × 0.012 λ relative to its wavelength. Furthermore, this antenna demonstrates exceptional stability in its polar patterns and maintains a high-efficiency level, achieving a substantial gain of 3.75 dBi with an efficiency rating of 84.5%. These remarkable attributes make this antenna suitable for a wide range of applications, including Wi-Fi, 5G, WLAN, and various other microwave communication scenarios. [ABSTRACT FROM AUTHOR]

The demand for compact, efficient, and versatile antennas has surged in tandem with the rapid evolution of wireless communication technologies. In response, this paper presents a pioneering Quadport-based fractal compact MIMO antenna designed to meet the stringent requirements of modern communication systems. The antenna incorporates a circular-shaped fractal radiating element and a stub-loaded ground region with a Partial ground, resulting in a significant enhancement of isolation performance. Through iterative optimisation, involving the integration of Partial ground, loading stubs, and fractals into the patch area, the antenna achieves optimal dimensions of 0.66λ × 0.83λ while operating across five distinct frequency bands, thereby catering to a wide range of multiband applications. Remarkable performance metrics are demonstrated, including peak isolation of 35 dB and minimum return loss of − 25.80 dB, alongside a peak electric field of 5.51 × 103 V/m. The polarization response for various resonating frequencies is meticulously analysed. The diverse parameters such as Total Active Reflection Coefficient < − 10, Mean Effective Gain around 0, Diversity Gain is around 10, Channel Capacity Loss < 0.2, and Envelope Correlation Coefficient < 0.1 are achieved. Utilising FR4 material for design enables mass production feasibility, further enhancing the antenna's practicality. Comparative analysis against existing literature underscores its superiority, positioning it as an ideal candidate for applications in 6G networks, WiMax, and weather monitoring. Overall, this Quadport-based fractal compact MIMO antenna represents a significant advancement in antenna offering a compelling blend of compactness, multiband capability, and exceptional performance metrics essential for the next generation of communication applications. [ABSTRACT FROM AUTHOR]

Background: Nowadays, healthcare systems are coping with the challenge of countering the exponential growth of healthcare costs worldwide, to support sustainability and to guarantee access to treatment for all patients. Methods: Artificial Intelligence (AI) is the technology able to perform human cognitive functions through the creation of algorithms. The value of AI in healthcare and its ability to address healthcare delivery issues has been a subject of discussion within the scientific community for several years. Results: The aim of this work is to provide an overview of the primary uses of AI in the healthcare system, to discuss its desirable future uses while shedding light on the major issues related to implications within international regulatory processes. In this manuscript, it will be described the main applications of AI in various aspects of health care, from clinical studies to ethical implications, focusing on the international regulatory framework in countries in which AI is used, to discuss and compare strengthens and weaknesses. Conclusions: The challenges in regulatory processes to facilitate the integration of AI in healthcare are significant. However, overcoming them is essential to ensure that AI-based technologies are adopted safely and effectively. [ABSTRACT FROM AUTHOR]

Microstrip patch antennas are becoming increasingly popular because they are small, have low profiles, are easy to integrate, are very cheap, and work well. For this reason, this antenna could be used for wireless communication systems. This research paper reviews and studies 28 GHz microstrip patch antenna for wireless applications. Different substrate materials have been used to make these antennas, such as FR-4 (loss), FR-4 Epoxy, Rogers RT/droid 5880, TLC-30, Rogers RT/droid 5880 LZ, and others. Different substrate materials and shapes were used to make microstrip patch antennas with a frequency of 28 GHz. This article discusses the different sizes of antennas, the other geometric shapes antennas can take, the different ways antennas' properties can be analyzed, and the different types of antennas. It will also talk about the material, thickness, loss tangent, return loss, bandwidth, voltage standing wave ratio (VSWR), gain, efficiency, and directivity of the substrate. This antenna is used for super-high-frequency (SHF), radars, commercial wireless local area networks (LANs), cell phones, and other wireless communications systems. [ABSTRACT FROM AUTHOR]

In order to provide solution to limited network resources in heterogeneous wireless networks supporting different applications with distinct quality of service (QoS) requirements, call admission control (CAC) schemes are implemented. This work is aimed at investigating three mostpopular CAC schemes employedin mobile worldwide interoperability for microwave access (WiMAX), namely dynamic CAC with bandwidth reservation (DCACBR), QoS-aware CAC (QoSACAC), and QoS guaranteed CAC (QoSGCAC) to identify their shortfalls which will form the focus of future research. A general platform is developed and simulated. The simulation was based on the following KPIs: blocking rate, dropping rate, and throughput for new and handoff connections. Simulation results for new connection shows that QoSGCAC outperforms scheme DCACBR and QoSACAC, having 26.9% and 8.56% improvements in throughput and 63.11% and 24.17% in blocking rate respectively. For handoff connection, QoSACAC showed the best performance having 13.25% and 47.84% improvements in throughput and 6.8% and 49.3% in blocking rate as compared to the DCACBR and QoSGCAC, respectively. Result analysis shows that QoSACAC has the best performance however, it admits new connections and degrade existing connections but failed to consider the delay-intolerant service classes. It is recommended that the QoSACAC be further improved. [ABSTRACT FROM AUTHOR]

This letter constitutes a novel triple-band reconfigurable filtering antenna used for Bluetooth, WiMAX and WLAN applications. First, a compact triple-band reconfigurable filter is instigated which is composed of two pairs of Stepped Impedance Resonators (SIRs) and a pair of Uniform Impedance Resonators (UIRs). The SIRs are entrenched at the upper and lower half of feed lines operating at 2.4 and 5.4 GHz, respectively. A pair of UIRs operating at 3.5 GHz is folded and enclosed near the upper SIR. A shunt stub is tapped at the source-load feeding lines to upgrade the selectivity of the filter. The proposed filter uses four PIN diodes to initiate different reconfigurable multiband operations. A fractal antenna is implemented with a modified binary tree topology. The ground plane of the proposed antenna is reformed with a stub. The improved antenna structure enables three radiating bands with enhanced performance. Later, the designed filter is integrated into the antenna to implement the intended triple-band reconfigurable filtering antenna. [ABSTRACT FROM AUTHOR]

We have presented two-port MIMO antenna designs with low-profile material. Two different MIMO antenna designs are prepared and investigated to observe their effect on the gain, bandwidth, etc. The designs are prepared based on metasurface concepts with one design having a circular ring metasurface design and second having circular disk metasurface design. The designs are showing broadband response covering frequency range of 1.85 GHz to 4.27 GHz. The bandwidth of 2.320 GHz is achieved for this metasurface MIMO antenna design. The gain and directivity results show that highest gain of 5.88 dB and directivity of 6.39 dB are achieved with circular ring metasurface MIMO antenna design. Both metasurface MIMO antenna designs are fabricated, and measured results are also provided to verify the simulation results. The broadband and high gain design are applicable for 5G communication, WiMAX and WLAN applications. [ABSTRACT FROM AUTHOR]

Pass band and stopband frequency selective surface (FSS) structures are extensively applicable in several wireless technologies to pass or stop desired frequency spectrums. A compact single layered frequency selective surface (FSS) with band stops and bandpass characteristic is formed by metal strips of extended Swastika shape on Rogers TMM-4 dielectric with overall periodic component size of 0.19λL × 0.19λL × 0.01λL (λL is wavelength at lowest stopband frequency) is reported in this letter that offers polarization independent and certain (up to 45°) angular insensitive characteristics. The FSS experimental analysis offers dual stopband resonances at 5.45 GHz and 16.1 GHz with bandwidth of 30.9% (4.6–6.28 GHz) and 27.66% (13.58–17.94 GHz) where decent association with full wave and circuit simulation results are attained. The FSS also offers passband resonance at 8.1 GHz. Apart from conventional wireless filtering and reflector applications, the FSS is also suitable for EM shielding applications. Further to proof the design concept, the FSS design parameters are upscaled to realize the WiMAX (3.3–3.8 GHz) stopband coverage. The upscaled similar shaped FSS of periodic component size 0.187λL × 0.187λL gives double stopbands at 2.96–4.18 GHz and 9.2–12.04 GHz and passband resonance at 5.6 GHz. [ABSTRACT FROM AUTHOR]

This paper presents a compact and wideband square microstrip patch antenna using low cost and easy available FR‐4 substrate of ground size 30 mm × 30 mm (0.51 × 0.51λ02 at lowest resonant frequency 5.07 GHz). The radiating patch of antenna is designed by embedding three T‐shape notches of same dimension formed by two rectangular notches of size 6 mm × 5 mm and 3 mm × 2 mm. The radiating patch is optimized by parametric variation of notches and feed line. The wideband fractional bandwidth (S11 < −10 dB) of 47.2% (2810 MHz) is achieved from 4.55 to 7.36 GHz with good return loss of −47.27 dB at 5.07 GHz for an optimized dimension of notches and feed line. However, the measured fractional bandwidth of 43.9% (2340 MHz) is achieved from 4.16 to 6.50 GHz with return loss of −37.34 dB at 5.14 GHz. A stable simulated gain of 4.69 to 5.93 dBi and measured gain of 4.4 to 5.9 dBi is observed in complete resonating band. The antenna is excited by line feed of 50 Ω and simulated by IE3D simulation tool. The entire resonating band 4.55–7.36 GHz is suitable for different applications in C‐band (4–8 GHz). [ABSTRACT FROM AUTHOR]

A compact, coplanar waveguide (CPW)-fed multiband antenna is developed and analyzed in this paper for quad-band applications. Christmas tree-like monopole antennae with three symmetric slots are designed on a low-cost FR4 epoxy substrate with the overall dimensions of 0.312λ1 × 0.364λ1 × 0.0083λ1 where λ1 is the wavelength corresponding to the lower cut-off frequency. Three rectangular-shaped slots of different dimensions are etched on the three triangular-shaped stacked patches to enhance the current carrying path due to which the proposed antenna resonates at the required frequency bands. Different antenna parameters such as reflection coefficient (S11), gain, radiation efficiency, surface current, radiation pattern, group delay and magnitude response of transfer function (S21) are analyzed for inspecting the antenna performance. The quad-band antenna offers measured bandwidths of 3.1–3.9 GHz (22.86%), 5.46–5.98 GHz (9.1%) 9.76–11.74 GHz (18.42%) and 17.55–19.25 GHz (9.24%). The antenna shows nearly omnidirectional radiation patterns in all resonating bands with the highest gain of 4.5 dBi and measured radiation efficiency greater than 70% in all the bands. The antenna also offers stable group delay response and linear S21 response in its operational spectrums. All these characteristics ensure the antenna's applicability in IEEE 802.16 WiMAX band, 5.5 GHz Wi-Fi band, 5.8 GHz ISM band, terrestrial broadband, radiolocation and earth explorer satellite applications. [ABSTRACT FROM AUTHOR]

A novel multiband metamaterial (MTM) unit cell antenna loaded with split ring resonator (SRR) slots that resonates at seven bands, which are (1.91 GHz), (3.6 GHz), (6.25 GHz), and (8.69 GHz, 9.69 GHz, 10.70 GHz), and 12.33 GHz of the spectrum, making it suitable for L-band, worldwide interoperability for microwave access (WiMax), C-band, X-band downlink, and Ku-band applications, respectively, is proposed and discussed in this work. The proposed antenna has a very compact size of 14×15×1.6 mm³ with an FR4 substrate. The simulation results show that the presented antenna attains a reflection coefficient of less than -10 dB (S11 -10 dB) and a radiation pattern across all operating bands. In addition, the suggested antenna provides good gains over the resonant frequency signals with an average of 6.75 db. The antenna simulations and parametric studies have been done using both computer simulation technology microwave studio (CST microwave studio) and high frequency structure simulator (HFSS) to confirm the obtained simulation results. [ABSTRACT FROM AUTHOR]

In this work, a wideband magneto-electric dipole antenna with circular polarization is introduced, which covers the 2G, 3G, LTE, and 5G frequency bands. In the proposed antenna, a planar dipole antenna with triangular corners, which plays the role of an electric dipole with circular polarization radiation, is mounted on a vertically-oriented cavity, which acts like a magnetic dipole. A Y-shaped probe is used to excite the antenna, which improves the axial ratio (AR) diagram due to its unique geometry. A sample of the proposed antenna is fabricated, and its measurement results are presented. The measurement results show an impedance bandwidth of 81.46% from 2.35 to 5.58 GHz, which covers the entire bandwidth required for 5G applications. Also, the measured 3-dB AR bandwidth extends from 2.26 to 5.58 GHz (84.61%). The measurement results show a relatively stable gain over the whole band, with a maximum gain of 9.91 dB at 4.8 GHz. One of the most significant advantages of the magneto-electric dipole antenna is its high front-to-back ratio (F/B). This advantage is also achieved in the proposed antenna, resulting in a maximum measured F/B of 29.3 dB. The simulated and measured results show a good agreement. [ABSTRACT FROM AUTHOR]

The manuscript represents a metamaterial-inspired superstrate patch antenna with a multiband response. The design consists of three superstrate layers over the patch antennaand SRRloaded over parasitic patches. The performance observation is carried out for 2–10 GHz. The simulation and fabrication are taken into consideration, and comparisonsbetween both of them are included. FR4 is used as a substrate material which helps reduce the structure's cost. The metamaterial approach is incorporated over superstrate regions for the improvement of results. The superstrate approach helps for enhancing the strength and Bandwidth of the design. Impedance response is analyzed for different resonating frequencies to check the metamaterial response. Two types of Parametric Analysis are considered to achieve the targeted goal, like changing feed position and the gap among superstrate layers. The presented work shows eight bands of reflectance response with a minimum value of − 44.83 dB with a Bandwidth of 3.139 GHz, peak directivity of 3.16 dB, a gain of 8.02 dB at 9.04 GHz, maximum E-field distribution of 1.160 × 105 v/m at 6.52 GHz. Presented work compared with other design structures to identify the improvement. Many wireless communication-related applications like military, WiMAX, and Maritime mobile services. [ABSTRACT FROM AUTHOR]

More and more CubeSats are being launched. On these small platforms, subsystems such as propulsion and communication ones have to coexist. This article focuses on electromagnetic interaction between these two critical subsystems. Hence, a numerical multi-physics method is proposed in order to quantify perturbation caused by an electric thruster's plume on the antenna of a CubeSat type spacecraft. A plume simulation model has been coupled with electromagnetic simulation software. As an example, the farfield radiation patterns and radioelectric characteristics of a 436 MHz dipole are presented when located near a Hall thruster's plume on a 6U type platform. Changes in radiation patterns are observed in the presence of plume for the dipole antenna. This versatile method makes it possible to represent microwave propagation through a plume for various antennas, thruster's plumes, or relative positions. [ABSTRACT FROM AUTHOR]

The IETE Journal of Research's first issue of Volume 70 covers a wide range of topics in communications, electromagnetics, opto-electronics, computers and computing, control engineering, electronic circuits, devices and components, instrumentation and measurement, medical electronics, and power electronics. The articles in this issue discuss various subjects, including improved network performance in wireless sensor networks, machine learning-based classification of cervical cancer, optimal energy reduction in 5G communication systems, and secure data transmission in the Internet of Things. The issue also includes papers on photonic sensors, detection of diabetic retinopathy, optimisation models for home health care scheduling and wind-integrated power systems, and efficient task scheduling in cloud computing environments. One research paper introduces a smartwatch-based machine learning model for monitoring epilepsy and detecting seizures, achieving a high accuracy of 99.40% in cross-validation. The document provides a summary of articles published in the journal, with authors who are experts in their fields and provide experimental findings and simulations to support their research. [Extracted from the article]

A novel low-profile, compact tri-band linearly and dual-sense circularly polarized (CP) antenna realized using via-less epsilon negative transmission line (ENG-TL) is investigated in this paper. The antenna miniaturization has been achieved by the zeroth-order resonance (ZOR) property of ENG-TL, which is actuated by connecting closed-loop octagonal ring radiator to an elliptical stub through a meandered-line structure. Circular polarization is accomplished by etching an L-shaped slot in the partial ground plane. The measured S11 result demonstrates that the proposed antenna features triple-band characteristics spanning from 2.42 to 2.50 GHz, 3.29 to 3.59 GHz and 5.43 to 5.55 GHz with centre frequencies of 2.46, 3.44, and 5.49 GHz, respectively. The antenna is offering linear polarization (LP) in the first and third bands while radiates left-handed CP in the + Z direction in the second band. An exceptional axial ratio (AR) of 0.062 dB has been achieved at 3.49 GHz with 3 dB axial ratio bandwidth (ARBW) extending from 3.35 to 3.67 GHz. This antenna offers an average simulated gain of 1.7 dBi across the CP band while 2.06, 1.75 and 3.67 dBi are acquired at 2.59, 3.53 and 5.62 GHz, respectively. Beside low-profile (0.013λ0 height) and miniaturized size (0.287λ0 × 0.205 λ0), intended antenna exhibits extended −10 dB impedance bandwidth, wide 3 dB AR bandwidth and reasonable radiation performance. It covers relevant frequency bands; therefore, it has the potential to be employed in 2.5 GHz LTE/UMTS, 3.5 GHz WiMAX, and 5.5 GHz WLAN applications. [ABSTRACT FROM AUTHOR]

In the proposed communication, a 2 × 2 and 4 × 4 antenna array with the capability of rejecting dual interfering bands is presented for multiband wireless applications including Ultrawideband (UWB) and X-band. Reconfiguration of notched bands is controlled using high-frequency switching devices (RF-PIN diodes). MIMO antenna configuration is formed by the combination of the Fork-shaped patch providing wideband bandwidth with Γ-T-shaped stub attached with the patch, which acts as bandstop filters for WiMAX and WLAN bands on one plane. Novel Ω-shaped ground is printed on the opposite plane, which provides good matching of impedance. The good matching of the results suggests accuracy in simulation and measurement environment with prototype in terms of frequency, time-domain, far-field and diversity MIMO performance. [ABSTRACT FROM AUTHOR]

Purpose: In wireless communication system, use of multiple antennas for different requirements of system will increase the system complexity. However, reconfigurable antenna is maximizing the connectivity to cover different wireless services that operate different frequency range. Pattern reconfigurable antenna can improve security, avoid noise and save energy. Due to their compactness and better performance at different applications, reconfigurable antennas are very popular among the researchers. The purpose of this work, is to propose a novel design of S-shaped antenna with frequency and pattern diversity. The pattern and frequency reconfiguration are controlled via ON/OFF states of the PIN diode. Design/methodology/approach: The geometrical structure of the proposed antenna dimension is 18 × 18 × 0.787 mm3 with εr = 2.2 dielectric constant. Three S-shaped patches are connected to a ring patch through PIN diodes. The approximate circumference of ring patch is 18.84 mm and length of patch is 5 mm, so approximate length of radiating patch is 14.42 mm and effective dielectric constant is 1.93. Conductor backed coplanar waveguide (CPW) is used for feeding. The proposed antenna is designed and simulated on CST microwave studio and fabricated using photolithography process. Measurements have been done in anechoic chamber. Findings: Antenna shows the dual band operation at 2.1 and 3.4 GHz frequency. The first band remains constant at 2.1 GHz resonant frequency and 200–400 MHz impedance bandwidth. Second band is switched at seven different resonant frequencies as 3.14, 3.45, 3.46, 3.68, 3.69, 3.83 and 3.86 GHz with switching of the diodes. The −10 dB bandwidth is more than 1.4 GHz. Research limitations/implications: Pattern reconfigurability can be achieved using mechanical movement of antenna easily but it is not a reliable approach for planar antennas. Electronic switching method is used in proposed antenna. Antenna size is very small so fabrication is very crucial task. Measured results are deviated from simulation results due to fabrication error and effect of leads of diodes, connecting wires and battery. Practical implications: The reconfiguration of the proposed antenna is controlled via ON/OFF states of the three PIN diodes. The lower band of 2.1 GHz is fixed, while second band is switched at five different resonant frequencies as 3.27, 3.41, 3.45, 3.55 and 3.88 GHz, with switching of the PIN diodes with all state of diodes and exhibit pattern reconfigurability at 2.1 GHz frequency. At second band center frequency is significantly changed with state of diodes and at 3.4 GHz pattern is also changed with state of diodes, hence antenna exhibits frequency and pattern reconfigurability. Originality/value: A novel design of pattern and frequency reconfigurable antenna is proposed. Here, work is divided into two parts: first is frequency reconfiguration and second is radiation pattern reconfiguration. PIN diodes as switch are used to select the frequency band and reconfigure the radiation pattern. This proposed antenna design is novel dual band frequency and pattern reconfigurable antenna. It resonates at two distinct frequencies, i.e. 2.1 and 3.4 GHz, and has a pattern tilt from 0° to 355°. The conductor backed CPW feed technique is used for impedance matching. [ABSTRACT FROM AUTHOR]

This work presents a printed monopole antenna with a miniature size and enhanced wideband using characteristic mode analysis (CMA). The printed monopole antenna structure comprises one vertical and one horizontal monopole, and a ground plane with a vertical extension. By connecting the horizontal monopole to the ground plane extension through a via hole, a significant enhancement in bandwidth is achieved in both lower and high bands. A 105% increment in bandwidth is achieved with the via hole compared to without it. The influence of the via hole is analyzed using CMA to provide a physical insight into the design. The proposed antenna is compact with an electrical size of 0.01 λ2, leading to a miniaturized design. [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 paper presents a compact, novel, quad patch and triple band single substrate microstrip patch antenna for 5G/6G mm wave applications. The aim is to design an antenna within the K-band with three resonance frequencies at 24, 29, and 34 GHz. The antenna is designed on a volumetric dimension of 11×12.7×1.6 mm³. The substrate used is FR4 (dielectric constant 4.4), having a loss tangent of 0.0022. A microstrip line of width 1 mm for a 50 O impedance line is used to match with the load antenna, which has four rectangular connected patches. Patch dimensions come from standard antenna equations and simulation done on Ansys High-Frequency Structure Simulator software. Validation of simulated results is done through measurements on the prototype antenna. A substantial good agreement is found between the simulated and measured results. The gain of the proposed antenna is 6.16 dBi, with return loss being ≨-10 dB. Bandwidths are 1.1 GHz (23.8 - 24.9 GHz), 0.9 GHz (28.6 - 29.5 GHz), and 0.8 GHz (33.7 - 34.5 GHz), respectively. The far-field radiation characteristics of both E-plane and H-plane are also reported. The proposed design is suitable for mm wave applications, including smart vehicles, global positioning systems, radio frequency identifications, etc. [ABSTRACT FROM AUTHOR]

This letter presents a compact slotted pentaband inset-fed microstrip antenna designed to operate for UMTS, WLAN, WiMAX, C-band and X-band applications. By incorporating equispaced slots of same width and length and also the inset feeding, the antenna generates five bands, allowing for penta-band operation. The antenna is manufactured on an FR4 substrate and is excited by an SMA connector using a microstrip line. With its compact dimensions of 25x25x1.6 mm3, the antenna offers a simple structure. Based on the simulated and measured outcomes, the proposed antenna demonstrates numerous advantages, making it highly suitable for wireless communication systems. These advantages include its ability to operate in multiple bands, its percentage bandwidth, compact size, stable radiation pattern, ease of processing, and costeffectiveness. [ABSTRACT FROM AUTHOR]

This article reports the Modified Microstrip Feed Hybrid Rectangular Dielectric Resonator Antenna (RDRA). The proposed structure has a ground plane with a plus-shaped slot on an FR4 substrate with a height of 1.6 mm and dimensions of 38 mm x 35 mm. The proposed Dielectric resonator antenna is made of a material with 10 as its dielectric constant, and the dimensions of the DR are 19 x 20 x 18 mm3. The DR is connected to a modified microstrip feed with an octagonal ring through the plus-shaped slot in the ground. The proposed structure operates in frequencies from 2.60 GHz - 2.74 GHz, 3.12 GHz - 3.37 GHz, and 4.25 GHz - 4.37 GHz. The resonant frequency of the final proposed RDRA is 2.68 GHz, 3.26 GHz, and 4.31 GHz, which covers WLAN, WIMAX and Wireless Avionics Intra-Communications (WAIC) applications, respectively. The entire structure was simulated using the CST microwave studio. The simulated results agree with the measured results and both are presented. The compact size, stable radiation pattern and reasonable gain make this antenna suitable for the proposed applications. [ABSTRACT FROM AUTHOR]

A single-substrate-layer Frequency Selective Surface (FSS) is designed with a 1.6 mm thick FR4 substrate for triple band-stop frequency filtering applications, that are for Bluetooth, WLAN, WiMAX, and X-band. The proposed FSS unit cell consists of two polygon loops on the front side and a square loop with four annular rings attached to its corners on the backside. The offered design covers three frequency bands: 2.3-4 GHz, 5-6 GHz, and 8-12 GHz. There are three resonances at 3.3, 5.6, and 9.9 GHz. The equivalent circuit model of the proposed structure and the formulas of the LC parameters are presented. A prototype of this structure was manufactured in size of 26 × 26 cm2 and experimentally verified in the antenna and microwave laboratory. The software used for design and simulation is HFSS from Ansys, which uses the finite element method. A comparison with similar structures was performed to demonstrate the performance of the proposed structure. The advantages of the proposed filter include adequate bandwidth, simple structure, as well as small size. In addition, it is unaffected by variant angles of incidence for TE polarization and TM polarization. Furthermore, due to its symmetrical design, it shows a polarization-independent feature. Experimental results for both polarizations verify the merits of the proposed approach, as shown before in the simulation results as well. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) era is driving up demand for wireless connectivity, changing the tech sector. The creation of a compact, inexpensive, and effective antenna is crucial for supporting IoT devices. In this study, a hybrid strategy (HS)-based dense rectangular patch antenna for future Internet of Things applications (IoT) is demonstrated. A slotted patch and a partial ground with defected ground structure (DGS) are combined to create HS, leading to in a small antenna with a large impedance bandwidth, good impedance matching, increased radiation efficiency, and high gain. The antenna is designed on an FR4_epoxy substrate with a compact size of 30 × 20 × 0.8 mm3, a dielectric constant of 4.4, a thickness of 0.8 mm, a loss tangent of 0.02 and fed by a 50 O microstrip feed line. It is analyzed and simulated at the operating frequency of 5.2 GHz for ultrawideband (UWB) (3.1-10.6 GHz) applications using high-frequency structure simulator (HFSS) software. The simulation results reveal that the antenna offers a broad bandwidth of 19.9 GHz (3.10 GHz to 23 GHz), a gain of 7.97 dB with an efficiency of 0.9651 (96.51%). The radiation pattern is bidirectional in both the E-plane and H-plane. Hence, the proposed antenna is very promising for future IoT applications due to its compact size and wide bandwidth characteristics. It also enhances connectivity and performance, lowers interference, opens up new applications, and encourages the widespread use of IoT technology, ultimately leading to the development of a more sophisticated and connected society. [ABSTRACT FROM AUTHOR]

Internet connectivity in WiMAX networks, along with various applications, is increasing rapidly, so the connectivity of internet and data transfer speed are always challenges for effective data transmission in wireless networks. Several factors affect the performance of networks. One important factor is to choose a suitable frame period for effective data transmissions. The performance of different frame periods with Round Robin and Strict Priority is evaluated in this work. A frame period in Round Robin performs better than a Strict Priority in terms of throughput, but a Strict Priority performs better in terms of drop rates. This paper also demonstrates that an effective frame period, when combined with a proper bandwidth allocation algorithm, yields better results. This work gives the analysis that Round Robin performs 83.8847% better while Strict Priority performs 86.0020% better than the earliest deadline first algorithms for 10 subscriber stations in terms of throughput. This work is helpful to researchers and industrialists for actual implementations in WiMAX networks. [ABSTRACT FROM AUTHOR]

This study aims to build a wireless computer network for a large company or university to enhance mobility and allow university users to stay connected at any time or place, which is achieved by applying the Universal Interoperability for Microwave Access (WiMax) technology. WiMax is based on the 802.16 sets of standards and has the most efficient and advanced hardware capabilities to meet the demands of teachers and students to browse the web or download files quickly. OPNET Modeler version 14.5 was used to determine the quality of service parameters of WiMax. [ABSTRACT FROM AUTHOR]

Summary: This paper overcomes two key issues within radiation monitoring networks. Secure and accurate transmission of detected gamma radiation in remote areas is the first challenge. The second one is related to the robustness of transmitted signal under different fading scenarios. These issues are handled during signal transmission over worldwide interoperability for microwave access (WiMax) networks. The signals are experimentally captured using a 137Cs point source, a NaI (TI) detector, and an analog‐to‐digital converter with 16 MS/s. For the first issue, several algorithms are implemented for secure and efficient transmission of gamma‐based signals. These algorithms include encoding of captured signal, decoding, interleaving, and frequency transformation of modulated signal. Encoding and decoding of target signals are conducted using the Reed Solomon technique and convolutional encoding with a Viterbi decoder. A superior algorithm for channel interleaver using the combinational interleaving method is introduced. Fast lifting transform (FLT) is applied for transforming modulated signal into frequency domain. The results declare that CC = 1/2 with BPSK‐1/2 coding rate introduces a better BER of 0.00068. A higher SNR of 1.5 dB is accomplished by the combinational interleaving algorithm. For the second issue, several models are suggested for overcoming channel degradations under gamma, exponential, Poisson, and geometric fading. Closed‐form expressions that describe outage probability, bit error rate (BER), and symbol error rate (SER) are suggested. Geometric and gamma fading achieve respectively a lower BER of 0.18 and 0.48. These channels demonstrate similar channel performances at 3.6 dB. The proposed models are validated through comparison with published work. Finally, the proposed algorithms enable higher data rate transmission of detected 137Cs signals under higher robustness using WiMax networks. [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]

An edge fed, dual band, quarter-wave transformer coupled, monopole, ultra-wideband (UWB), dodecagon-shaped miniaturized frequency reconfigurable antenna for ISM and wireless applications is designed, analysed and investigated. The impedance transformer is utilized in the structure for impedance matching and hence results in lower reflection coefficient values. The antenna uses defected ground structure (DGS) in the bottom and radiating patch that is practically loaded with three numbers of delta structures. The use of DGS reduces the value of gain and provides ultra-wideband bandwidth across the designed frequency. The addition of three delta structures in the patch improves the value of gain. Miniaturizing in the size of the antenna has been achieved by reducing the ground along the width that led to a total 30.41% size reduction in the fundamental circular patch antenna. The antenna exhibits two bands 1.82–3.61 GHz and 5.24–12.43 GHz thus antenna is suitable for ISM band, PCS, 5G, Wi-Fi/WiMAX/WLAN and other wireless applications. The fabricated antenna is frequency reconfigured by utilizing the switching property of four numbers of PIN diodes (BAP64-02V). Frequency reconfigurable antenna is used flexibly and versatile for various microwave applications based on the switching conditions (more than eight digital combination cases) of PIN diodes. The prototype measured results provide good agreements with the simulated reflection coefficients values in some mode of operations. Antenna radiating patch and ground is etched on FR-4 substrate of dimension 52 mm × 59 mm × 1.6 mm using printed circuit board technology. [ABSTRACT FROM AUTHOR]

This paper proposes a four-level iterated snail shell-inspired wideband microstrip fractal patch antenna for Internet of Things (IoT) applications. The antenna comprises a snail-shell-inspired radiating patch, a metallic partial ground plane with a notch, and a microstrip feedline. A modal study has been performed with the help of Characteristics Mode Analysis. The notch and partial ground plane contributed to separating the overlapping modes and reducing the quality factor, which enhanced bandwidth. In order to excite multiple modes and to attain the wider bandwidth, the surface current distribution for various modes has been examined. The antenna uses a low-cost FR-4 substrate with a dielectric constant of 4.4 and a 1.6 mm substrate height. The overall dimensions of the antenna are 40 mm × 40 mm × 1.6 mm. The proposed antenna operates between 2.2 GHz and 5 GHz, with a radiation efficiency of 92%, an impedance bandwidth of 166%, and a peak gain of up to 2 dBi. The simulated antenna performance in terms of S11, VSWR, and gain has been validated using Vector Network Analyzer (VNA) measurements in an anechoic chamber. At 2.4 GHz, an omnidirectional radiation pattern has been observed. The proposed antenna covers Wi-Fi 802.11 standard 2.4 GHz, WiMax (2.5 GHz to 2.7 GHz), WLAN (2.4 GHz–2.48 GHz), 5G (3.6 GHz), and Avionics (4.9 GHz, 4.2 GHz to 4.4 GHz), Industrial Internet of Things (IIoT) in 2.4 GHz applications. [ABSTRACT FROM AUTHOR]

This paper presents a highly isolated pattern diversity multiband MIMO antenna using two ring-shaped radiating elements with a rectangular stub placed inside it. The proposed multiband MIMO antenna is resonating at three frequencies centred at 2.45 GHz, 3.5 GHz, and 5.4 GHz. A high-quality factor U-shaped bandstop filter is designed and placed between the two antenna elements to achieve simultaneous high isolation and pattern diversity. The isolation between the antenna elements at 2.45 GHz, 3.5 GHz, and 5.4 GHz is −25 dB, −20 dB and −35 dB, respectively. The diversity gain is 10 dB, while the ECC is less than 0.05. The antenna is fabricated on a low-cost substrate, FR4, and its dimensions are 31 mm × 31 mm × 0.8 mm. Measured results verify the multiband behaviour of the proposed MIMO antenna. The proposed MIMO antenna is useful for WLAN, WiMAX and 5 G sub-6 GHz-based applications. [ABSTRACT FROM AUTHOR]

This paper presents a hepta-band planar monopole antenna which exhibits circular polarization (CP) at two bands and linear polarization at other five bands. Combination of rectangular slots to form a single E-shaped structure has been introduced in half ground to excite hepta-band operations. Asymmetric trapezoidal parasitic element is also placed under the monopole radiator positioned at upper half ground plane of antenna. Due to asymmetric effect attained by the placement of trapezium, CP is achieved at 4.2 GHz and 10 GHz with 3-dB axial ratio bandwidth of 4.21–4.29 GHz and 9.92–10.01 GHz, respectively. The antenna acquires remaining five resonant modes at 2.4 GHz, 5.4 GHz, 7.2 GHz, 8.86 GHz and 11.8 GHz with 10-dB impedance bandwidth of 90 MHz, 160 MHz, 100 MHz, 200 MHz and 410 MHz, respectively. Sensitive study of the E slot and trapezoidal structured geometry is conducted. The proposed antenna is designed on low cost FR4 (εr = 4.4, tanδ = 0.02). To ensure the practicability, the proposed antenna design is fabricated and measured. A good agreement of simulation and measurement validates the proposed designed. The antenna has potential to cover frequency bands of IEEE802.11, Bluetooth, WLAN, WiMAX, Satellite Communication, Short Range RADARs and Radio band applications. [ABSTRACT FROM AUTHOR]

This paper presents the design of a simple dual-band circularly polarized monopole antenna using characteristic mode analysis. First, a dual-band elliptically polarized "L"-shaped monopole antenna with a partial ground is designed; then, a rectangular stub and a parasitic structure on the ground plane are implemented to achieve dual-band CP operation. To enhance impedance bandwidth and generate circular polarization in the upper band, the rectangular stub is attached to the "L"-shaped strip. The parasitic structure is employed for simultaneous dual-band CP radiation. Characteristic mode analysis is undertaken to predict the performance of the antenna before excitation. The modal analysis which is undertaken before excitation shows the natural modes that can be excited by the antenna structure to generate a dual-band CP response. The analysis gives approximate bandwidths that can be achieved by the antenna even before excitation. The overall dimension of the antenna is 0.379 λ 0 × 0.379 λ 0 × 0.015 λ 0 , where λ 0 is the corresponding free-space wavelength at 5.7 GHz. The measured -10 dB impedance bandwidth (ZBW) is realized to be 75.9% (4.5 GHz–10 GHz). The measured 3 dB axial ratio bandwidths (ARBW) at the lower and upper bands are 6% (5.6 GHz–5.95 GHz) and 28% (6.65 GHz–8.82 GHz), respectively. The proposed antenna features a simple and compact structure for Wi-Fi, WLAN, WiMAX, and C band applications. [ABSTRACT FROM AUTHOR]

The Non Line of Sight (NLOS) broadband wireless access provided by Worldwide Interoperability for Microwave Access (WiMAX) operating in 2-11 GHz frequency is susceptible to the effects of multipath propagation, diffraction fading, vegetation attenuation, shadowing loss etc. In order to overcome these effects effective fade mitigation techniques, have to be implemented. The Orthogonal Frequency Division Multiplexing-Multiple Input Multiple Output (OFDM-MIMO) is an efficient method that helps in combatting the fading and providing higher SNR to the WiMAX system. According to the IEEE 802.16 specification, for QPSK modulation, a threshold SNR of 6 dB is required for the link to operate. In the present work the use of OFDM-MIMO achieves a SNR above this operating threshold. [ABSTRACT FROM AUTHOR]

In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication. [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]

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]