Enhancement Of Power Transmission Research Articles

Wireless Energy-On-Demand Using Magnetic Quasi-Resonant Coupling

This article proposes and implements a novel magnetic quasi-resonant coupling (MQRC) scheme to realize the concept of energy-on-demand wireless power transfer (WPT). To prevent illegal receivers harvesting wireless energy, the proposed energy-on-demand technology nominates the authorized receiver to take over the initiative and generate a well-defended security key based on a two-dimensional frequency-and-duration chaos. The switched-capacitorless quasi-resonant transmitter flexibly employs a new continuous operating frequency regulation strategy to self-adapt the arbitrary energy-on-demand from the authorized receiver, hence achieving synchronous multifrequency WPT. Moreover, the proposed MQRC-WPT system takes the merit of power transmission enhancement over conventional one while improving the transmission efficiency especially during low power level. Theoretical analysis, electromagnetic simulation, and practical experimentation are provided to verify the feasibility of proposed energy-on-demand MQRC-WPT system with security.

Electric Power Transmission Enhancement: A Case of Nigerian Electric Power Grid

Increase in economic activities resulting from increase in population and social advancement has led to increase in electrical energy demands. This has increased the burdens on the existing transmission assets and in some cases, has caused the loading of the transmission assets beyond their design limits with consequent reduction in power quality and power outages in extreme cases. Many techniques have been developed to enhance the capabilities of the power grids. This paper looks into these techniques with the view to exploring their applicability to the Nigerian 330KV electric power grid, towards seeking ways to enhancing the performance of the grid for better asset utilization. A typical transmission line in the grid was modeled to assess its strengths and weaknesses. Enhancement techniques were then applied to assess their impacts on the line.

이식형 보청기에 의한 자기공명 영상의 인공음영 축소를 위한 외부 코일 시스템 설계

Recently, several implantable hearing aids such as cochlear implant, middle ear implant, etc., which have a module receiving power and signal from outside the body, are frequently used to treat the hearing impaired patients. Most of implantable hearing aids are adopted permanent magnet pairs to couple between internal and external devices for the enhancement of power transmission. Generally, the internal device which containing the magnet in the center of receiving coil is implanted under the skin of human temporal bone. In case of MRI scanning of a patient with the implantable hearing aid, however, homogeneous magnetic fields of the MRI might be interfered by the implanted magnet. For the above reasons, the MR image is degraded by large area of artifact, so that diagnostics are almost impossible in deteriorated region. In this paper, we proposed an external coil system that can reduce the artifact of MR image due to the internal coupling magnet. By finite element analysis estimating area of MR artifact according to varying current and shape of the external coil, optimal coil parameters were extracted. Finally, the effectiveness of the proposed external coil system was verified by confirming the artifact at real MRI scan.

FSS-based approach for the power transmission enhancement through electrically small apertures

In this paper, a novel approach, based on the employment of frequency selective surfaces, to enhance the power transmission through sub-wavelength apertures at the microwave frequencies is presented. A heuristic interpretation of the phenomenon is given, as well as an analytical model, based on the transmission line network representation. Finally, the performance of the proposed structure is validated through a set of full-wave numerical simulations.

The Effect of Insulating Layers on the Performance of Implanted Antennas

This work presents the analysis of the influence of insulation on implanted antennas for biotelemetry applications in the Medical Device Radiocommunications Service band. Our goal is finding the insulation properties that facilitate power transmission, thus enhancing the communication between the implanted antenna and an external receiver. For this purpose, it has been found that a simplified model of human tissues based on spherical geometries excited by ideal sources (electric dipole, magnetic dipole and Huygens source) provides reasonable accuracy while remaining very tractable due to its analytical formulation. Our results show that a proper choice of the biocompatible internal insulation material can improve the radiation efficiency of the implanted antenna (up to six times for the investigated cases). External insulation facilitates the electromagnetic transition from the biological tissue to the outer free space, reducing the power absorbed by the human body. Summarizing, this work gives insights on the enhancement of power transmission, obtained with the use of both internal, biocompatible and external, flexible insulations. Therefore, it provides useful information for the design of implanted antennas.

Achieving Power Transmission Enhancement by Using Nano-Rings Made of Silver Spheres

In this letter, we propose the employment of nano-rings made of silver spheres, to enhance the transmission through a subwavelength aperture drilled in a metallic screen at optical frequencies. We show that the increase in the transmission is due to the excitation of a strong magnetic resonance in close proximity of the aperture. Compared to similar configurations presented in the literature, the proposed layout allows us to significantly reduce the size of the setup. The effectiveness of the approach is demonstrated through proper full-wave simulations, taking into account material dispersion and losses. In addition, it is shown how the nano-ring response can be tuned by embedding the structure in a host material, doped with liquid crystals.

Power transmission enhancement by means of planar meta-surfaces

In this paper, the analysis and design of a planar meta-surface based on dipoles and wires is presented. The unit cell is formed by three layers, two parallel dipoles and one continuous wire. The transmission response and dispersion diagram of the unit cell are analysed step by step in order to determine the effect of each element; one dipole, two parallel dipoles and finally the two dipoles and wire unit cell. For a normally incident plane wave excitation with the E field parallel to the wires and the H field axial to the dipoles, a strong magnetic dipole moment is induced which produces a pass band around the resonant frequency and a stop band at higher frequencies. This cell is used to create meta-surfaces for antenna gain enhancement. Two configurations are analysed; the first one is a superstrate of a dipole antenna with the pass band tuned to the resonant frequency of the dipole. Due to the resonance of the superstrate inclusions, a uniform illumination is achieved, which produces high aperture efficiency and an increase of the directivity up to 6.31. By adding a meta-substrate with the stop band tuned to the resonant frequency of the dipole, an enhancement versus the conventional dipole of five times in the boresight radiation and 795 times in the front–back ratio is obtained.