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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]

Two dominant driving forces for evolving communication technologies in the current society have been the proliferation of wireless access networks to the Internet and the broadbandization of access and infrastructure networks. Through these evolutions of communication technologies, high-resolution contents are instantly delivered to wireless devices such as mobile phones, wireless tablets, and headsets. Recently, wireless sensor networks, where up to 1000 low-power sensors are wirelessly connected to each other, have been created and connected to the Internet, which presents a new challenge of efficiently coordinating the transmissions of many wireless sensors with minimal transmission overheads. Developing an efficient Medium Access Control (MAC) protocol governing the transmissions of wireless sensor networks is crucial for the success of wireless sensor networks for the realization of the Internet of Things (IoT). In 2023, the node insertion algorithm was proposed to efficiently derive the minimal number of serially connected multipolling sequences of many wireless sensors, by which Access Points (APs) can poll wireless sensors with minimal polling overheads. In this paper, the combined sweeping and jumping method is presented to dramatically enhance the searching performance of the node insertion algorithm. To validate the performance of the combined sweeping and jumping method, simulation results are presented for wireless sensor networks where wireless sensors with varying transmission ranges exist. [ABSTRACT FROM AUTHOR]

This communication presents the design analysis and development of a compact, dual-band, circularly polarized, multilayer antenna for global positioning system (GPS), wireless local area network (WLAN), and Industrial Scientific, and Medical (ISM) applications. The antenna comprises two etched strip radiator and reflector layers on two Kapton substrates situated at a vertical distance of 18.47 mm. The inverted U-strip results in WLAN/ISM band from 2.30–2.62 GHz whereas the semi-circular arc-strip is responsible for generating the lower band from 1.46 to 1.73 GHz. The bottom surface reflector plane is applied below the main antenna radiator which results in a unidirectional radiation pattern with improved front-to-back ratio (FBR), antenna gain, radiation efficiency, and specific absorption rate (SAR). The reflector contains an inner square ring with a circular center ring. The reflection coefficient below −10 dB fractional bandwidth (FBW) is suitable for GPS/ISM/WLAN/Wi-Fi/Bluetooth etc operations. The maximum gain of 5.82 dBi is obtained at a frequency of 2.80 GHz. The antenna is designed on a flexible Kapton substrate of a size 28 × 31 mm². The SAR values below 0.01 W/kg and 0.02 W/kg are obtained at two resonance frequencies 1.60 GHz and 2.41 GHz, respectively. Therefore, the designed antenna is most suitable for indoor/outdoor wearable tracking purposes and also for medical applications. [ABSTRACT FROM AUTHOR]

The advancement of wireless communication technology demands antennas that can achieve significant gain while functioning across diverse frequency ranges. Numerous studies have aimed to enhance the gain and radiation properties of such antennas. However, when these antennas operate near the human body, their performance regarding return loss, gain, radiation pattern, and specific absorption rate (SAR) are influenced by the interaction and absorption of human tissue. To enhance overall antenna performance, artificial magnetic conductor (AMC) surfaces have been introduced. Numerous studies have been conducted to improve antenna performance through the use of AMC surfaces. This paper proposes a coplanar waveguide (CPW)-fed wearable antenna integrated with an AMC array. The integrated antenna is expected to operate at both 2.45 GHz and 5.5 GHz, making it suitable for applications in wireless local area networks (WLAN) and wireless body area networks (WBAN). The study focuses on the benefits of the integrated antenna, highlighting advantages such as improved gain and lowered SAR in comparison to the antenna alone. These improvements are validated through both simulated and measured outcomes. This antenna, featuring a simple feed structure, low cost, and ease of fabrication, is a promising option for wearable medical applications. [ABSTRACT FROM AUTHOR]

Wireless local area networks (WLANs) play a crucial role in the internet of things (IoT) landscape, facilitating constant data exchange among devices. However, the inherent security vulnerabilities in these networks, stemming from limited computational resources, pose significant challenges to deploying robust security measures. This research addresses the security concerns surrounding IoT devices within the IEEE 802.11ah WLAN environment by introducing the SecureScanML algorithm, a novel machine learning (ML) approach designed to optimize Internet-wide port scans (IWPS) for enhanced device security while preserving network performance. The SecureScanML algorithm leverages Q-learning, a reinforcement learning technique, to dynamically adjust the scan rates of IoT devices adaptively. Through this approach, the algorithm effectively reduces vulnerabilities, achieving a notable 35.7% reduction, while maintaining key network performance metrics. With a throughput of 2.8 Mbps, a packet delivery ratio of 97.3%, an adaptability index of 0.91, a convergence speed of 420 s, and a low latency of 42 ms, the proposed algorithm surpasses existing methods such as TA, RA, SSR, CNN-LSTM, RLA, and RSR. Simulation results corroborate the efficacy of SecureScanML in mitigating vulnerabilities without compromising network efficiency. The algorithm strikes a fine balance between proactive vulnerability management and network performance preservation. Moreover, the study explores the impact of security-performance weight parameters on the algorithm's behavior, providing valuable insights for fine-tuning the system to achieve specific security and performance objectives. Notably, for a security-performance weight of 0.5, the algorithm demonstrates high throughput and vulnerability reduction alongside low latency. [ABSTRACT FROM AUTHOR]

Wireless local area networks (WLANs) have recently evolved into technologies featuring extremely high throughput and ultra-high reliability. As WLANs are predominantly utilized in Internet of Things (IoT) and Wi-Fi-enabled sensor applications powered by coin cell batteries, these high-efficiency, high-performance technologies often cause significant battery depletion. The introduction of the trigger frame-based uplink transmission method, designed to enhance network throughput, lacks adequate security measures, enabling attackers to manipulate trigger frames. Devices receiving such frames must respond immediately; however, if a device receives a fake trigger frame, it fails to enter sleep mode, continuously sending response signals and thereby increasing power consumption. This problem is specifically acute in next-generation devices that support multi-link operation (MLO), capable of simultaneous transmission and reception across multiple links, rendering them more susceptible to battery draining attacks than conventional single-link devices. To address this, this paper introduces a Secure Triggering Frame-Based Dynamic Power Saving Mechanism (STF-DPSM) specifically designed for multi-link environments. Experimental results indicate that even in a multi-link environment with only two links, the STF-DPSM improves energy efficiency by an average of approximately 55.69% over conventional methods and reduces delay times by an average of approximately 44.7% compared with methods that consistently utilize encryption/decryption and integrity checks. [ABSTRACT FROM AUTHOR]

This study addresses the limitations of wireless local area networks in indoor localization by utilizing Extra-Trees Regression (ETR) to estimate locations based on received signal strength indicator (RSSI) values from a radio environment map (REM). We investigate how integrating numerous access points can enhance indoor localization accuracy. By constructing an extensive REM using RSSI data from various access points collected by a mobile robot in the intended interior setting, we evaluate several machine learning regression techniques. Our research pays special attention to an optimized ETR model, validated through 10-fold cross-validation and hyperparameter tuning. We quantitatively evaluate the efficiency of our suggested multi-access-point approach using root mean square error (RMSE) for REM evaluation and location error metrics for accurate localization. The results show that incorporating multiple access points significantly improves indoor localization accuracy, providing a substantial improvement over single-access-point systems when assessing interior radio frequency environments. [ABSTRACT FROM AUTHOR]

Over the past years, remote sensing, radar, and imaging applications have all made use of ultra-wideband (UWB) technology. This study undertakes an extensive analysis of tree-shaped monopole antennas tailored for UWB systems. The intended antenna has an incomplete ground plane and a circular radiating patch. To increase bandwidth, two ears have been added to the circular structure. Possessing a dielectric constant of 4.3. The antenna substrate consists of FR-4 material with a dielectric constant of 4.3. To achieve optimal impedance matching for UWB systems, the antenna is fed via a coplanar waveguide (CPW). Design antenna is a simple structure, small size, easy design, and simple integration with the substrate with dimensions of 54 mm ×36 mm ×1.6 mm. All simulation results presented in this article were generated using computer simulation technology (CST) software. He monopole antenna exhibits an impressive impedance bandwidth of 9.6 GHz (146.68%), spanning from 1.99 GHz to 11.56 GHz. Furthermore, the simulated UWB circular monopole antenna exhibits omnidirectional radiation characteristics, boasting a peak gain of 8 dB, and a directivity of 8.2 dBi at the frequency of 5 GHz, and a remarkable radiation efficiency of 97%. With these attributes, the suggested monopole UWB antenna shows significant potential for ground penetrating radar (GPR) applications. [ABSTRACT FROM AUTHOR]

This research designs, analyzes, and studies a 2.45 GHz rectangular microstrip patch antenna (RMPA). The antenna design uses Rogers RT5880 (lossy) substrate material with 2.2 dielectric permittivity, 1.5 mm thickness, and 0.0009 loss tangent. Additionally, the antenna was designed and simulated using computer simulation technology (CST) studio 2019 software. Plot designs were again created using Origin Pro Software. The simulation results showed that the return loss (S11), voltage standing wave ratio (VSWR), gain, directivity, bandwidth, efficiency, and surface current were -45.992 dB, 1.0101, 6.115 dBi, 6.534 dBi, 70.8 MHz, 93.59%, and 49.9 A/m, respectively. This paper aims to increase return loss to a typical VSWR value near 1. Besides boosting antenna gain, directivity, and efficiency, it can be used in future wireless applications, including mobile phones and wireless LANs. The proposed antenna design outperforms earlier experiments, demonstrating that the research has increased performance. [ABSTRACT FROM AUTHOR]

This study presents a quad-band stub-incorporated split octagonal ring antenna specifically designed for wireless applications that rely on satellite communication. The antenna is fabricated on an FR4 substrate with dimensions of 26×21×1.6 mm³ and its performance is simulated using the CST EM Studio software. The device operates in the frequency range from 2.15 GHz to 6.35 GHz, using stub integration and gap modification to achieve resonant bands. The antenna has resonant frequencies of 2.23 GHz, 3.28 GHz, 4.77 GHz, and 5.89 GHz, with corresponding bandwidths of 153 MHz, 9011 MHz, 7692 MHz, and 6813 MHz, respectively. The parametric analysis optimizes the values of the design parameters, while the experimental validation shows the consistency between the measured and simulated results. The antenna is characterized by a small size, a consistent radiation pattern and a wide range of applications including ISM, WIFI, WLAN, WIMAX, 5G, and C-Band Satellite. The device is capable of operating in two frequency bands and consistently maintains a gain of over 1 dBi across its resonating range. [ABSTRACT FROM AUTHOR]

In large indoor environments, accurate positioning and tracking of people and autonomous equipment have become essential requirements. The application of increasingly automated moving transportation units in large indoor spaces demands a precise knowledge of their positions, for both efficiency and safety reasons. Moreover, satellite-based Global Positioning System (GPS) signals are likely to be unusable in deep indoor spaces, and technologies like WiFi and Bluetooth are susceptible to signal noise and fading effects. For these reasons, a hybrid approach that employs at least two different signal typologies proved to be more effective, resilient, robust, and accurate in determining localization in indoor environments. This paper proposes an improved hybrid technique that implements fingerprinting-based indoor positioning using Received Signal Strength (RSS) information from available Wireless Local Area Network (WLAN) access points and Wireless Sensor Network (WSN) technology. Six signals were recorded on a regular grid of anchor points covering the research surface. For optimization purposes, appropriate raw signal weighing was applied in accordance with previous research on the same data. The novel approach in this work consisted of performing a virtual tessellation of the considered indoor surface with a regular set of tiles encompassing the whole area. The optimization process was focused on varying the size of the tiles as well as their relative position concerning the signal acquisition grid, with the goal of minimizing the average distance error based on tile identification accuracy. The optimization process was conducted using a standard Quantum Particle Swarm Optimization (QPSO), while the position error estimate for each tile configuration was performed using a 3-layer Multilayer Perceptron (MLP) neural network. These experimental results showed a 16% reduction in the positioning error when a suitable tile configuration was calculated in the optimization process. Our final achieved value of 0.611 m of location incertitude shows a sensible improvement compared to our previous results. [ABSTRACT FROM AUTHOR]

This study introduces an innovative four-port millimeter-wave (mm-wave) Multiple Input Multiple Output (MIMO) antenna tailored for 5 G applications. Fabricated with a compact size of 25 mm x 25 mm, the antenna employs Rogers RT Duroid 5880 material, which has a thickness of 0.8 mm. This research introduces a high-gain, compact MIMO antenna addressing limitations discussed in related literature, operating at 37–39 GHz and ideal for mm-wave applications due to its small size, low profile, and efficient radiation capability. The antenna operates in the range of 37–39 GHz, with an impressive 10 dB impedance bandwidth. Impressively, the isolation among antenna elements reaches 25 dB, achieved by maintaining an edge-to-edge distance between elements of just 5.45 mm and employing orthogonal arrangements. Through rigorous experimentation, the antenna demonstrates substantial performance metrics, achieving directivity and gain of up to 8 dB and 5 dB, respectively. The fabricated antenna undergoes thorough measurement, and all results are found to be well-correlated with simulated results. This emphasizes the reliability and accuracy of the proposed design. The study establishes the antenna as a suitable contender for future mm-wave applications, providing valuable insights into the potential of compact MIMO configurations in the high-frequency spectrum. The achieved performance metrics and reliable measurements position the proposed design as a promising candidate for advancing communication systems and emerging technologies in the mm-wave domain [ABSTRACT FROM AUTHOR]

In recent years, with the increasing number of terminal connections, high-density deployment scenarios have become important scenarios for future wireless networks. Ultra-high throughput (EHT) in high density deployment scenarios is the technical goal of IEEE 802.11be, the next-generation wireless local area network (WLAN) standard. However, in a high-density deployment scenario, interference suppression between BSSs is serious, which seriously affects the throughput of a WLAN. And the resources available are limited. Therefore, for the next generation WLAN standard, this paper proposes a downlink transmission scheme based on AP coordination and the orthogonal frequency division multiple access (OFDMA) protocol and the non-orthogonal multiple access (NOMA) protocol, named Co-OFDMA–NOMA scheme. The core idea is to transform the interference and suppression relationship between neighboring BSSs into the relationship of mutual coordination and assistance through the Co-OFDMA–NOMA protocol proposed in this paper. Firstly, a downlink transmission scheme named the Co-OFDMA–NOMA protocol is designed. In addition, the protocol and its framework structure have good backward compatibility. Theoretical analysis shows that the proposed Co-OFDMA–NOMA protocol has significant performance gain, and simulation results prove the effectiveness of the scheme. [ABSTRACT FROM AUTHOR]

To solve the problem of antenna miniaturization and mutual interference between the communication band of the UWB system and other wireless communication system bands, this paper proposes a UWB monopole antenna which has frequency notch characteristics. By applying two pairs of Split Ring Resonator (SRR) structures on a CPW transmission line, a coupling resonance is generated in a specific frequency band, and the antenna has a dual frequency notch and a wide band notch function. The measured results show that the antenna has good band-notch characteristics in the frequency ranges of 3.3 GHz to 4 GHz and 5.1 GHz to 6.2 GHz, suppressing ultra-wideband interference between WiMAX (3.3 GHz ~ 3.8 GHz) and WLAN (5.15 GHz ~ 5.35 GHz and 5.725 GHz ~ 5.825 GHz) in a wireless communication system. The volume of the antenna is 40 mm × 36 mm × 1 mm, and the measured results are compared with the simulated model results. Besides, the measured and simulated results have a good consistency. [ABSTRACT FROM AUTHOR]

Wireless network attacks are some of the most common network security threats dealt with daily. Their ease of execution and effectiveness make them commonplace within most public networks. The goal of this paper is to develop a tool which provides defenses against these attacks, one which can also generate the attacks to test its own effectiveness in defending against them. The research involved the design, testing, and implementation of attacks/defenses tool, which benefits from a user-friendly user interface that simplifies the testing process. The attacks were generated using existing tools, linked to one central interface. The defense methodology was scriptbased and created entirely from scratch. It was also linked to a single interface which continuously monitors logs to detect and prevent attacks in an efficient timely manner. The results showed that the proposed defenses to the studied wireless attacks were effective at mitigation, or outright prevention. They were also more lightweight than existing solutions, making them more appealing for less powerful hardware. [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: 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]

Wireless Local-Area Networks (WLANs), as a popular internet access solution, are widely used in numerous places, including enterprises, campuses, and public venues. As the number of devices increases, large-scale deployments will cause the problem of dense wireless networks, including a lot of energy consumption. Thus, the optimization of energy-efficient wireless AP devices has become a focal point of attention. To reduce energy consumption, we have proposed the active access-point (AP) configuration algorithm for WLANs using APs with a dual interface. This uses the greedy algorithm combined with the local search optimization method to find the minimum number of activated APs while satisfying the minimum throughput constraint. However, the previous algorithm basically satisfies only the average throughput among the multiple hosts associated with one AP, wherein some hosts may not reach the required one. In this paper, to overcome this limitation, we propose an enhanced active AP configuration algorithm by incorporating the throughput request satisfaction method that controls the actual throughput at the target value (target throughput) for every host by applying traffic shaping. The target throughput is calculated from the single and concurrent communicating throughput of each host based on channel occupancy time. The minimum throughput constraint will be iteratively adjusted to obtain the required target throughput and achieve the fair throughput allocation. For evaluations, we conducted simulations using the WIMNET simulator and experiments using the testbed system with a Raspberry Pi 4B for APs in four topology cases with five APs and ten hosts. The results show that the proposed method always achieved the required minimum throughput in simulations as well as in experiments, while minimizing the number of active APs. Thus, the validity and effectiveness of our proposal were confirmed. [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]

The sequential layout of a portable ultra-wideband (UWB) monopole antenna, transforming into a compact band-notch (3.15–4.3 GHz rejecting the Wi-Max and the C-Band) multiple-input multiple-output (MIMO) antenna is described in this paper. The diversity layout is designed within a compact size of 39 (l) × 18 (W) mm2. Due to the opposite orientation of the two radiators in the diversity configuration and the use of a rectangular parasitic strip near the feed lines, high and wideband isolation (of >20 dB) is attained over the entire UWB spectrum. The proposed layout depicts a stable omnidirectional radiation pattern and a maximal gain of 1.82 dB. The envelope correlation coefficient (ECC) is found to be below 0.18 for the entire UWB spectrum. Empirical verifications in terms of vital diversity parameters and analogy with competing layouts strengthen the candidature of the intended MIMO layout for UWB wireless 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]

Significant advancement has been witnessed in the field of modern communication technology in last decade. Several wireless systems such as Wireless LAN, Wireless Fidelity (Wi-Fi) etc. are popular to connect devices to facilitate communication between them through internet technology. To access much faster communication, higher data rates are highly sought after with the upgradation of mobile communication generations (1G to 5G). Wideband/multiband antennas usually support multiple devices to get connected over a broad range of communication. As a benchmark of next generation communication technology, Internet of Things (IOT) is gaining a huge popularity in the field of wireless network. It ensures faster and secure communication among devices and cloud with high data rate. With this aim, we have proposed a new monopole antenna for IOT applications. The design consists of a new concentric ring based split ring patch and partial ground plane. It is implemented with characteristic mode analysis. The designed antenna operates in the ultra-wideband region with multiband characteristics at four bands of (1.5-1.9 GHz), (3.9- 4.2 GHz), (5.9-6.9 GHz) and (7.4-11.8 GHz) to cover for various IoT communication applications. The suggested design is inspected using analysis of characteristic mode, characteristic angle, eigen values, and modal significance. The distribution of surface current for the proposed circular shaped patch antenna is analyzed for mode of propagation by the theory of characteristic modes (CMA). [ABSTRACT FROM AUTHOR]

Printed antenna technology gained has become centre of attraction for designing MIMO antenna system for future communication applications. Antenna is an essential component for 5G communication system. MIMO technology is highly preferrable due to high data rate and simultaneous data transmission establishment. In this article, a curved slot incorporated circular shaped antenna is constructed and tested for performance utilizing conventional ground planes in an eventual Fifth Generation (5G) mobile communication network. The proposed single element system is operating from 2.6 to 12.9 GHz with an 85.84% efficiency throughout the band. The substrate of the radiator is 30 mm 30 mm 1.6 mm, where a circular patch is used whose size is 9.35 mm. A partial ground structure of 30 mm 10 mm is used to obtain high efficiency and wide bandwidth. The structured antenna system has a maximum directivity of 4.8, efficiency of 89%, and maximum gain of 1.68 dB which are desired in any MIMO system to tolerate interference and maintain user bandwidth. The proposed micro strip patch two element antenna covers 10 dB return loss frequencies from 2.6 GHz to 11.8 GHz than the conventional method. The total size of the MIMO antenna system is 70 mm 60 mm 1.6 mm. The 2-element MIMO antenna simulated results are determined by the HFSS software with their performance. [ABSTRACT FROM AUTHOR]

A novel, compact, monopole apple-shaped, triple-band metamaterial-printed wearable antenna backed by a uniplanar compact electromagnetic bandgap (UC-EBG) structure is introduced in this paper for wearable wireless and medical body area network (WBAN/MBAN) applications. A tri-band UC-EBG structure has been utilized as a ground plane to minimize the impact of antenna radiation on the human body and improve antenna performance for the proposed wearable antenna. Metamaterial triangular complementary split ring resonators (TCSRRs) are incorporated into the antenna and UC-EBG structure, resulting in a compact UC-EBG-backed antenna with an overall size of 39 × 39 × 2.84 mm3 (0.41 λg × 0.41 λg × 0.029 λg). The printed textile antenna operates at 2.45 GHz for the wireless local area network (WLAN), 3.5 GHz for 5G new radio (NR), and 5.8 GHz for the industrial, scientific, and medical (ISM) bands with improved gain and high-efficiency values. Furthermore, the performance of the antenna is analyzed on the human body, where three models of curved body parts are considered: a child's arm (worst case) with a 40 mm radius, an adult's arm with a 60 mm radius, and an adult's leg with a 70 mm radius. The results demonstrate that the proposed antenna is an attractive candidate for wearable healthcare and fitness monitoring devices and other WBAN/MBAN applications due to its compact size, high performance, and low SAR values. [ABSTRACT FROM AUTHOR]

This research paper covers a comprehensive investigation into the design, analysis, and performance evaluation of frequency reconfigurable antennas. The relentless advancement of wireless communication technology has necessitated the development of antennas that can adapt seamlessly to a wide range of operating frequencies. The proposed antenna design incorporates a circular ring configuration with a PIN diode for dynamic frequency tuning. The reconfigurable element allows for versatile operation across multiple frequency bands, avoiding the requirement for separate antennas and simplifying system integration. The performance evaluation encompasses key parameters such as radiation pattern, gain, bandwidth, and efficiency, assuring optimal performance across the specified frequency range. The measured and simulated results validate the accuracy and effectiveness of the recommended structure. The research findings contribute to the state-of-the-art advancements in frequency reconfigurable antenna engineering, enabling efficient wireless communication systems for several applications, such as cellular networks, WLANs, satellite communication systems, and cognitive radio networks. [ABSTRACT FROM AUTHOR]

This paper presents a compact 8×8 multiple-input-multiple-output (MIMO) antenna system designed to operate across two wide frequency bands suitable for fifth-generation (5G) mobile network and wireless local area network (WLAN) applications. Each antenna element comprises a radiator, a feeding line, and a defected ground plane. Each radiator consists of a first L-shaped radiator (FLR), a second L-shaped radiator (SLR), and an extra radiator (ER). To enhance the isolation, a defected ground structure (DGS) is employed between the antenna elements. The presented antenna operates across three frequency bands, namely, 3.5 GHz (3.3 GHz-3.8 GHz) and 4.9 GHz (4.8 GHz-5 GHz) 5G frequency bands, and 5.7 GHz (5.15 GHz-5.85 GHz) WLAN frequency band, exhibiting excellent isolation, surpassing 15 dB in both lower and higher frequency bands. The overall efficiency exceeds 58%, with an envelope correlation coefficient (ECC) value below 0.125. The simulation and measurement results are in good agreement. [ABSTRACT FROM AUTHOR]

A miniaturized ultra-wideband (UWB) antenna with quadruple reconfigurable characteristics is proposed in this paper. The first step involves the development of an elementary rectangular patch antenna of size 40 × 40 mm2, which is subsequently modified to demonstrate UWB properties. To incorporate quad-band notch features, the radiating surface of the patch antenna is etched with four Ushaped slots. The antenna has an impedance bandwidth ranging from 2.2 GHz to 12 GHz, with four specific notches located at 3.3 GHz (3.1-3.5 GHz), 3.8 GHz (3.6 GHz-4 GHz), 4.6 GHz (4.5 GHz-4.7 GHz), and 5.2 GHz (5.1 GHz-5.3 GHz). By incorporating four PIN diodes, the antenna is capable of attaining a range of sixteen reconfigurable states across the UWB spectrum. The design of this system successfully addresses the issue of interference caused by WiMAX, downlink C-band, Indian national satellite system, and Wireless LAN. A prototype is fabricated and tested. The simulated and experimental results are in good agreement. [ABSTRACT FROM AUTHOR]

This research presents an innovative dual-band microstrip patch antenna design enhanced with defected ground structures (DGS) and barium strontium titanate (BST) thin film, tailored for wireless local area network (WLAN) and WiMax applications. The first design phase involved the development of an microstrip patch antenna (MPA) using an flame retardant (FR4) substrate with a permittivity (er1) of 4.3 and a thickness of 1.524 mm, enhanced with DGS. This configuration achieved a single-band resonance at 4.1 GHz, with a bandwidth of 0.82 GHz and a return loss (S11) of -32 dB. The second phase involved the integration of a BST thin film, with a high permittivity(er2) of 250 and a thickness of 0.1 mm, into the DGS-enhanced microstrip patch antenna (MPA). This modification led to a transformation in the antenna's performance, enabling dual-band operation at resonance frequencies of 2.8 GHz and 5.8 GHz. Further, there was a corresponding substantial increase in bandwidth to 1.34 GHz and 1.25 GHz, respectively, an improvement in S11 values to -16.3 dB and -21.4 dB. Moreover, and antenna's size of 14×10×1.524 mm³. The study underscores the critical role of innovative material use and design optimization in advancing antenna technology, offering significant enhancements in bandwidth, and miniaturization, for wireless communication systems. [ABSTRACT FROM AUTHOR]

Antenna operates at single frequency can be wielding for any one application. If the antenna has to be wield for multiple operations the number of antennas will increase, which in turn increases system size. The proposed printed antenna with novel spiral shaped slot having circular dumble shaped defective structure results in multiple bands can overcome the stated limitation. Printed patch antenna is designed and simulated using High Frequency Structure Simulator software using Glass epoxy substrate. The proposed antenna has a dimensions of 3.34 × 2.47 × 0.16 cm with low cost substrate shows five different working frequencies with good return loss having impedance bandwidth of 7.93% with highest gain of 9.92 dB and virtual size reduction of 28.33%. The proposed antenna is resonating between 4.36 and 15.89 GHz which covers L, C, Ku and K band application. [ABSTRACT FROM AUTHOR]

This paper presents a broadband high-isolated MIMO antenna operating in the C and X bands simultaneously. The antenna is expected to be applied in wireless systems such as satellites and radar. A modified Vivaldi element is firstly designed by etching a rectangular structure out of the top metal, and then arranged symmetrically to form a 2-element broadband MIMO antenna with element spacing of 0.28λ (λ is the wavelength at 9 GHz). The operating frequency the MIMO antenna in terms of S11 ≤ −9.0 dB is from 4.0 GHz to 13.5 GHz. However, the mutual coupling between the two elements is quite strong, which can be as high as 8.0 dB, indicating a severe mutual coupling effect between the elements. To improve the isolation level, a defect-ground structure (DGS) is designed and loaded on the ground plane. The decoupling structure of the DGS achieves decoupling in the C and X bands, with a particular emphasis on decoupling in the C band by blocking the current flow between antenna elements. The simulated result shows that the S21 can be lowered to less than −23.4 dB across the whole operating frequency region, i.e., an isolation improvement of 15 dB is achieved. A prototype is fabricated and measured. The measured results are in good agreement with the simulated ones, indicating that the designed broadband MIMO antenna is a good candidate for reliable communication in the C and X bands. [ABSTRACT FROM AUTHOR]

This paper introduces a 4-port antenna tailored for 5G, operating in the 4.4 to 7.25 GHz (Fractional Bandwidth is 48.9%) range with a 10 dB impedance bandwidth. The operating bandwidth includes the n79 band (4.4–5 GHz), 5G WLAN band (5.125–5.825 GHz), and Wi-Fi 6E band (5.925 to 7.125 GHz). Constructed on a compact FR4 substrate (0.057λ × 0.057λ × 0.0018λ (where λ is the wavelength at 4.4 GHz), it exhibits robust performance in fabrication and measurements. The single antenna covers a total area as small as 20×17.6 mm², which enables the compactness of the MIMO antenna with a gain of up to 6 dBi and 85% radiation efficiency; it supports MIMO with a low correlation coefficient (< 0.02), high diversity gain (up to 9.98 dB), and minimal channel capacity loss (0.25 bps/Hz). The Total Active Reflective Coefficient (TARC) is computed to validate MIMO performance over the operating bandwidth. Featuring bidirectional radiation patterns in both E-plane and H-plane, the antenna is well suited for 5G applications, demonstrating potential for future wireless systems. [ABSTRACT FROM AUTHOR]

This document serves as an introduction to a special issue on wireless sensor networks (WSNs), explaining their structure and applications in various sectors. It also discusses the challenges faced by WSNs, such as limited energy and data management. The special issue features ten research papers on advanced WSNs. [Extracted from the article]

The latest edition of the IETE Journal of Research (Volume 70, Number 6, June 2024) features 45 articles covering a diverse range of topics including communications, electromagnetics, computers and computing, control engineering, electronic circuits, devices and components, instrumentation and measurement, medical electronics, and power electronics. The journal has also appointed three new Deputy Editors-in-Chief to the Editorial Board. The articles delve into various subjects such as wireless communication systems, PAPR reduction in OFDM systems, deep learning classifiers for 5G D2D communication, optimization techniques for IoT relay communication systems, rain attenuation prediction models, adaptive beamforming using convolutional neural networks, and antenna designs for different applications. Other papers explore topics such as geometry word problem resolution, XSS attack detection, video traffic reduction in 5G networks, breast cancer detection in MRI images, multimodal brain image fusion, melanoma skin disease detection, speech enhancement techniques, land cover change detection, medical image encryption, multimedia computation offloading in 5G networks, and priority-based scheduling in hybrid VANETs. These papers provide valuable insights and contribute to the existing body of knowledge in their respective fields. [Extracted from the article]

A miniaturized edge-fed multi-band wideband (WB) sensor complementary split ring resonator (CSRR) and two folded pedal arms loaded antenna for wireless, ISM, military, Radar, and satellite applications is fabricated, tested, and investigated. The reduced ground plane at the bottom to makes the gain positive and leads to improvement in the radiation efficiency. Loading of antenna patch with two folded bicycle pedal-shaped arms results in an increased total electrical length and hence antenna could be tuned up to higher frequency bands. The appended two folded pedal arms enhance the value of gain and CSRR loading introduces additional resonant frequencies below −10dB reflection coefficient. The symmetrical ground width compression results in total antenna size miniaturization to 43.33% concerning the conventional circular microstrip antenna designed at a frequency of 2.45GHz. The antenna has a bidirectional radiation pattern with a gain of 5.21dBi and a radiation efficiency of 90.50%. The antenna exhibits four bands (2.13–2.58GHz), (2.77–3.89GHz), (5.65–6.56GHz), and (7.77–12.98GHz) within a frequency sweep of 1–15GHz, therefore it, is the most suitable element for Bluetooth, PCS, ISM band, 3G/4G/5G, Wi-MAX/WLAN/ Wi-Fi, and wireless, satellite, military, and RADAR applications. These bands are frequency reconfigured by two BAP64-02V PIN diodes in the pedal-arms fold locations with four switching combinations. The measured (frequency sweep: 1–23GHz) and simulated antenna reflection coefficient values are found in match except for a frequency range of 12–14 GHz. The antenna was fabricated on a low-cost FR-4 that holds well <12 GHz frequencies, and >12 GHz frequencies values this shows nonlinear and frequency dispersion. [ABSTRACT FROM AUTHOR]

A novel compact dual-band antenna based on dual-cap metasurface (MS) is proposed. By etching circumferential circular ring slots on one side of the substrate and a large cruciform slot on the other side, the dual-cap MS operates in two frequency bands. In addition, by placing the dual-cap MS at the back of a circular ring planar antenna which serves as a reflector, the impedance characteristic of the antenna in lower band and gain both in two bands are improved. The results show that this dual-cap MS antenna operates in the Wireless Local Area Network (WLAN) bands of 2.43-2.6 GHz and 5.48-6.05 GHz. Moreover, the maximum gains in lower and upper bands can reach 6.9 and 5.8 dBi, respectively. [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 integration of the 60 GHz band into the IEEE 802.11 standard has revolutionized indoor wireless services. However, this band presents unique challenges to indoor wireless communication infrastructure, originally designed to handle data traffic in residential and office environments. Estimating 60 GHz signal propagation in indoor settings is particularly complicated due to dynamic contextual factors, making it essential to ensure adequate coverage for all connected devices. Consequently, empirical channel modeling plays a pivotal role in understanding real-world behavior, which is characterized by a complex interplay of stationary and mobile elements. Given the highly directional nature of 60 GHz propagation, this study addresses a seemingly simple but important question: what is the impact of employing highly directive antennas when deviating from the line of sight? To address this question, we conducted an empirical measurement campaign of wireless channels within an office environment. Our assessment focused on power losses and distribution within an angular range while an indoor base station served indoor users, simulating the operation of an IEEE 802.11ad high-speed WLAN at 60 GHz. Additionally, we explored scenarios with and without pedestrian movement in the vicinity of wireless terminals. Our observations reveal the presence of significant antenna lobes even in obstructed links, indicating potential opportunities to use angular combiners or beamformers to enhance link availability and the data rate. This empirical study provides valuable information and channel parameters to simulate 60 GHz millimeter wave (mm-wave) links in indoor environments, paving the way for more efficient and robust wireless communication systems. [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]

Breast cancer is a medical condition characterized by the uncontrolled proliferation of cells in the breast tissue. Breast cancer can originate from various parts of the breast, and methods such as Breast ultrasound, Diagnostic mammogram, Breast magnetic resonance imaging, and Biopsy are currently used for its diagnosis. However, these methods have certain limitations, and their size can be a hindrance. To overcome this, low-power, flexible antennas can be designed for bio-communication between medical equipment and external instrumentation. Flexible and wearable antennas have advantages such as affordability, ease of fabrication, and high gain. In this article, a microstrip patch antenna operating at 2.45 GHz and made of polyamide material is designed using High Frequency Structure Simulator software. The simulation results show the patch antenna has a gain of 1, −14.81 dB return loss at 2.45 GHz based on |S11| ≤ −10 dB. The directive radiation pattern with axial ratio of 63.39 dB and voltage standing wave ratio ≤ 3. Furthermore, the hardware development of proposed antenna with polyamide substrate provides the resonance frequency nearing to simulation results as 2.318 GHz with return loss of −28.19 dB. Based on mathematical analysis, simulation and hardware results, the proposed antenna is a superior option for breast cancer detection. [ABSTRACT FROM AUTHOR]

This paper introduces a square slot antenna with circular polarization and dual-band capability. The structure of the antenna is similar to an L-shape patch but with modifications in the lower rectangular part of the L, the patch has been transformed into a circle. Additionally, two strips having rectangular shape are located on the ground plane at opposite corners. By adjusting the size of the rectangular strips, the antenna can achieve dual-band and dual-sense circular polarization. The measured results of this design indicate that the Impedance Bandwidths are 45.16% (2.4–3.8 GHz) and 43.75% (5–7.8 GHz), while the Axial Ratio Bandwidths are 45.16% (2.4–3.8 GHz) and 37.4% (5–7.3 GHz) for the lower and upper bands respectively. [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]

Multi-link operation (MLO) is a new and essential mechanism of IEEE 802.11be Extremely High Throughput (Wi-Fi 7) that can increase throughput and decrease latency in Wireless Local Area Networks (WLANs). The MLO enables a Multi-Link Device (MLD) to perform Simultaneous Transmission and Reception (STR) in different frequency bands. However, not all MLDs can support STR due to cross-link or in-device coexistence interference, while an STR-unable MLD (NSTR-MLD) can transmit multiple frames simultaneously in more than two links. This study focuses on the problems when NSTR-MLDs share a link with Single-Link Devices (SLDs). We propose a Contention-Less Synchronous Transmission (CLST) mechanism to improve fairness between NSTR-MLDs and SLDs while increasing the total network throughput. The proposed mechanism classifies links as MLD Dominant Links (MDLs) and Heterogeneous Coexistence Links (HCLs). In the proposed mechanism, an NSTR-MLD obtains a Synchronous Transmission Token (STT) through a virtual channel contention in the HCL but does not actually transmit a frame in the HCL, which is compensated for by a synchronous transmission triggered in the MDL. Moreover, the CLST mechanism allows additional subsequent transmissions up to the accumulated STT without further contention. Extensive simulation results confirm the outstanding performance of the CLST mechanism in terms of total throughput and fairness compared to existing synchronous transmission mechanisms. [ABSTRACT FROM AUTHOR]