Akaa Agbaeze Eteng

Bio: Akaa Agbaeze Eteng is an academic researcher from University of Port Harcourt. The author has contributed to research in topics: Antenna (radio) & Wireless power transfer. The author has an hindex of 9, co-authored 33 publications receiving 211 citations. Previous affiliations of Akaa Agbaeze Eteng include Universiti Teknologi Malaysia.

Multiobjective Beampattern Optimization in Collaborative Beamforming via NSGA-II With Selective Distance

Abstract: Collaborative beamforming is usually characterized by high, asymmetrical sidelobe levels due to the randomness of node locations. Previous works have shown that the optimization methods aiming to reduce the peak sidelobe level (PSL) alone do not guarantee the overall sidelobe reduction of the beampattern, especially when the nodes are random and cannot be manipulated. Hence, this paper proposes a multiobjective amplitude and phase optimization technique with two objective functions: PSL minimization and directivity maximization, in order to improve the beampattern. A novel selective Euclidean distance approach in the nondominated sorting genetic algorithm II (NSGA-II) is proposed to steer the candidate solutions toward a better solution. Results obtained by the proposed NSGA with selective distance (NSGA-SD) are compared with the single-objective PSL optimization performed using both GA and particle swarm optimization. The proposed multiobjective NSGA provides up to 40% improvement in PSL reduction and 50% improvement in directivity maximization and up to 10% increased performance compared to the legacy NSGA-II. The analysis of the optimization method when considering mutual coupling between the nodes shows that this improvement is valid when the inter-node Euclidean separations are large.

Low-power near-field magnetic wireless energy transfer links: A review of architectures and design approaches

Abstract: The elimination of physical conductors as media for power transmission is an important step towards reducing the bulk of waste material generated when electronic gadgets are disposed of. In addition, the increasing deployment of low-power autonomous electronics in less accessible environments has provided an impetus for the development of wireless energy transfer alternatives to wired power delivery. This paper presents a review of near-field magnetic wireless energy transfer link architectures, and design approaches for realizing performance objectives specifically suited to low-power deployments. First, the paper provides a brief history of low-power magnetic wireless energy transfer development. This is followed by a fundamental description of the spatial regions surrounding an electromagnetic field source. Then, the paper presents a summary of basic topologies of magnetic wireless energy transfer link implementations, while emphasizing their distinctive features. Design approaches, which enable the realization of various link performance criteria, are also discussed. Finally, this paper highlights emergent wireless energy transfer link design trends inspired by communication network paradigms.

Wireless Nonradiative Energy Transfer: Antenna performance enhancement techniques.

Abstract: In recent times, wireless nonradiative energy transfer has elicited considerable research interest. Its varied applications range from contactless battery charging and power delivery to sensors, near-field communications, and radio-frequency identification (RFID). Antenna performance plays a key role in the successful deployment of a wireless energy transfer strategy. This article presents an integrated survey of metrics and methods that have been employed to evaluate and improve antenna performance in nonradiative energy transfer schemes.

A Review of Metasurfaces for Microwave Energy Transmission and Harvesting in Wireless Powered Networks

Abstract: Wireless energy transmission and harvesting techniques have recently emerged as attractive solutions to realize wireless powered networks. By eliminating fundamental power constraints arising from the use of conventionally battery sources, wireless modes of energy transmission provide viable means to power wireless network devices away from the grid. Metasurfaces have emerged as key enablers for the use of microwave energy as a power source. Their unique abilities to tailor electromagnetic waves have motivated significant research interest into their use for power-focused microwave systems. This article provides an overview of progress in the development of metasurface implementations for microwave energy transmitters and energy harvesters. First, the paper provides a basic introduction to metasurfaces, after which it reviews research progress in metasurfaces for microwave energy transmission and harvesting. Also highlighted are key parameters by which the performance of such metasurface designs are characterized. In addition, an overview of studies on metasurfaces as reconfigurable intelligent surfaces in wireless networks supporting the simultaneous transmission of information and energy is presented. Finally, the paper highlights existing challenges, and explores future directions, including opportunities to control radio environments through ambiently energized reconfigurable intelligent surfaces in next-generation wireless networks.

Two-Stage Design Method for Enhanced Inductive Energy Transmission with Q-Constrained Planar Square Loops.

Abstract: Q-factor constraints are usually imposed on conductor loops employed as proximity range High Frequency Radio Frequency Identification (HF-RFID) reader antennas to ensure adequate data bandwidth. However, pairing such low Q-factor loops in inductive energy transmission links restricts the link transmission performance. The contribution of this paper is to assess the improvement that is reached with a two-stage design method, concerning the transmission performance of a planar square loop relative to an initial design, without compromise to a Q-factor constraint. The first stage of the synthesis flow is analytical in approach, and determines the number and spacing of turns by which coupling between similar paired square loops can be enhanced with low deviation from the Q-factor limit presented by an initial design. The second stage applies full-wave electromagnetic simulations to determine more appropriate turn spacing and widths to match the Q-factor constraint, and achieve improved coupling relative to the initial design. Evaluating the design method in a test scenario yielded a more than 5% increase in link transmission efficiency, as well as an improvement in the link fractional bandwidth by more than 3%, without violating the loop Q-factor limit. These transmission performance enhancements are indicative of a potential for modifying proximity HF-RFID reader antennas for efficient inductive energy transfer and data telemetry links.

An overview of metamaterials and their achievements in wireless power transfer

Abstract: Metamaterials have been deployed for a wide range of fields including invisible cloak, superlens, electromagnetic wave absorption and magnetic resonance imaging, owing to their peculiar electromagnetic properties. However, few investigations on metamaterials were focused on wireless power transfer (WPT). WPT is the transmission of electrical energy from a power source to an electrical load without conductors like wires or cables. Metamaterials can enhance the transfer efficiency and enlarge the transfer distance due to their ability of focusing magnetic flux, which opens up a novel approach to promoting the development and application of WPT. This review paper aims to provide an overview of the fabrications, exotic properties, and their applications especially in the WPT field. Meanwhile, the perspective and future challenges of metamaterials and WPT are proposed.

Distributed and Collaborative Beamforming in Wireless Sensor Networks: Classifications, Trends, and Research Directions

Abstract: Distributed and collaborative beamforming (DCBF) scheme in wireless sensor networks (WSNs) is receiving new-found interest in recent times due to the rapid advancements in wireless technology and embedded systems. Although studies on distributed and collaborative beamforming have been carried out for more than ten years, the DCBF was initially considered impractical due to high complexity and hardly achievable requirements. It gained prominence only in the past few years as small wireless communication electronic sensors with high processing capability became easily available. Recent works showcasing distributed and collaborative beamforming as a suitable solution for 5G communication systems such as mm-wave communication and machine to machine communications has further ignited the interest in this research field. Motivated by these factors, this paper presents a survey on the research trends of distributed and collaborative beamforming in WSNs. We provide classifications of the DCBF research areas and conduct an extensive review of the various proposals which have appeared in the literature for each classification. This survey uncovered that majority of existing research can be broadly divided into four major research trends: beampattern analysis, power and lifetime optimization, synchronization, and finally, prototype design. The inherent features, constraints and challenges of each research category in the distributed and collaborative beamforming are presented and the lessons learned from the shortcomings of previous research are summarized. Finally, this paper has unveiled open research directions in the field of distributed and collaborative beamforming in WSNs.

A review of recent trends in wireless power transfer technology and its applications in electric vehicle wireless charging

Abstract: Recently, electric vehicles (EVs) are becoming increasingly popular, as they decrease reliance on fossil fuels and reduce greenhouse gas emissions. However, there are still many challenges hindering the adoption of EVs. For example, EVs have short driving ranges and long charging times. To overcome these challenges, wireless power transfer (WPT) is emerging as a promising solution. WPT enables the efficient wireless charging of EVs to increase driving range, while simultaneously decreasing battery size and improving convenience. This paper presents a comprehensive overview of recent trends in WPT technologies and applications to wireless charging of EVs. The fundamental principles of WPT are briefly explained. The state-of-the-art technical progress in the field of WPT is explored in detail. The latest applications of WPT to charging EVs are thoroughly investigated, including stationary and dynamic wireless charging. Moreover, the economic feasibility of stationary and dynamic wireless charging of EVs is analyzed. Finally, to address safety issues related to human exposure to electromagnetic fields (EMFs), methods for EMF shielding are proposed.

6G Wireless Communications: Future Technologies and Research Challenges

Abstract: 5G wireless communications technology is being launched, with many smart applications being integrated. However, 5G specifications meagre the requirements of new emerging technologies forcefully. These include data rate, capacity, latency, reliability, resources sharing, and energy/bit. To meet these challenging demands, research is focusing on 6G wireless communications enabling different technologies and emerging new applications. In this paper, the latest research work on 6G technologies and applications is summarized, and the associated research challenges are discussed.

The state-of-the-arts of wireless electric vehicle charging via magnetic resonance: principles, standards and core technologies

Abstract: With the growing adoption of electric vehicles (EVs), there is a pressing need for constructing charging infrastructures. In this context, wireless charging technology has been under development for the past few decades. Dispensed with awkward plugs and wires, wireless power transfer (WPT) technology is very safe, convenient and easy-to-use. Researchers have taken sustained efforts to make it an improved technology and automakers also work to provide the wireless charging option for their customers. In this paper, the basic principles of resonant inductive power transfer that is common-used for wireless electric vehicle charging (WEVC) are elaborated. Then, with a different emphasis on WEVC technologies, the key issues in academia and industry are discussed respectively. The core technologies of a fully-function WEVC system in academia are summarized and a comparative study is conducted among the selected WEVC industry standards. In addition, based on the possible technical development and currently valid policies, the author envisions the future of WEVC, followed by some conclusions and helpful advice.