Optimum transmitter receiver ratio for maximum wireless energy transfer

Due to high demand of using cordless mobile device, the interest in wireless energy transfer (WET) has been growth intensively. This paper presented a method to obtained optimum transmitter receiver ratio for maximum performance of WET system using different initial antenna size at various distance. An optimized algorithm has been developed to determine the optimum ratios that yield the highest wireless transfer efficiency (WTE) at near field communication (NFC) frequency, 13.56MHz. 30mm × 30mm single square loop antenna is used as initial size of both transmitter and receiver using FR4 with operating distance = 50mm. Operating distance and initial size of the antenna will be varied and the effect to the WTE will be studied using Matlab, verified using Microsoft Studio CST. At distance = 50mm and initial size of the antenna = 30mm × 30mm, optimum transmitter to receiver ratio equal to 1:3 is obtained. The pattern of optimum transmitter receiver ratio between Matlab and CST has met an agreement. This research limited to integer transmitter receiver ratio used only and no decimal number being involved in magnify the transmitter size

Analysis of Concentric Split Ring Square Element for Broadband Reflectarray Antenna

An investigation of phase variation and phase range of concentric split ring square element for broadband reflectarray antenna is presented in this paper. This is realized by exploiting the physical geometry of three element shapes namely square element, concentric ring square element and concentric split ring square element. Modifying the current distribution of basic concentric ring square element, leads to a less steep phase variation and also the bandwidth performance. An analysis of frequency response is described and analysed. The physical interpretation of the elements is also discussed. The proposed antenna element effectively covers two frequency operations (13.44 GHz and 18.36 GHz) in Ku-band range. Bandwidth broadening is achieved by introducing the ring square combination of element and the practical phase range is achieved through the use of RF 35 (thickness = 1.524 mm) as the substrate. The new concept of split initiates to a wider bandwidth (up to 67.6 %) for the antenna and can applied to any two frequency operations of Ku-band applications

Mechanical and wear properties of aluminum coating prepared by cold spraying

In this study, Al powders were deposited onto Al substrates using cold spray to form a coating. The main objective is to investigate and compare the microstructure, mechanical and wear properties of Al coating to that of the Al substrate. The microstructure of the coating and substrate were observed using Scanning electron microscope (SEM),hardness was evaluated using Vickers hardness test and wear properties were investigated using a pin on disc wear test machine

Characterizations of waste soil of open dumping area

The heterogeneous content of waste soil from dumping area are complicated to characterize and classified. The total number of dumping area has been increase with the increase of population in Malaysia. The content of waste dumped at the dumping area is important to analyze because the degradation process change with time. Three categories have been proposed in this paper namely Category I: Soil like and non-soil like, Category II: Waste types and Category III: Waste or Soil. The waste soil are analyzed based on its geotechnical properties such as particle size distribution, specific gravity, shear strength, settlement displacement, compaction curve and triaxial strength and mineral compositions. Two types of representatives samples were collected, one from dumping area at Sri Hartamas and one from non-dumping area located at Bukit Chuping area. The dumping area samples were named as waste soil. It can be concluded that the waste soil consists of high friction angle which range from 11 degrees to 38 degrees, settlement displacement of 0.5 mm/min to 3.5 mm/min for loading of 3 kg, 5kg and 7 kg of applied normal loads. The compaction curve of waste soil has the maximum dry density of 1489 kg/m3 to 1600 kg/m3 and the optimum moisture content of between 27% to 30%. These parameters are important in determining the long-term settlement of the open dumping area

Development of Ray Tracing Algorithms for Scanning Plane and Transverse Plane Analysis for Satellite Multibeam Application

Reflector antennas have been widely used in many areas. In the implementation of parabolic reflector antenna for broadcasting satellite applications, it is essential for the spacecraft antenna to provide precise contoured beam to effectively serve the required region. For this purpose, combinations of more than one beam are required. Therefore, a tool utilizing ray tracing method is developed to calculate precise off-axis beams for multibeam antenna system. In the multibeam system, each beam will be fed from different feed positions to allow the main beam to be radiated at the exact direction on the coverage area. Thus, detailed study on caustics of a parabolic reflector antenna is performed and presented in this paper, which is to investigate the behaviour of the rays and its relation to various antenna parameters. In order to produce accurate data for the analysis, the caustic behaviours are investigated in two distinctive modes: scanning plane and transverse plane. This paper presents the detailed discussions on the derivation of the ray tracing algorithms, the establishment of the equations of caustic loci, and the verification of the method through calculation of radiation pattern

Microwave brain imaging system to detect brain tumor using metamaterial loaded stacked antenna array

In this paper, proposes a microwave brain imaging system to detect brain tumors using a metamaterial (MTM) loaded three-dimensional (3D) stacked wideband antenna array. The antenna is comprised of metamaterial-loaded with three substrate layers, including two air gaps. One 1 x 4 MTM array element is used in the top layer and middle layer, and one 3 x 2 MTM array element is used in the bottom layer. The MTM array elements in layers are utilized to enhance the performance concerning antenna's efficiency, bandwidth, realized gain, radiation directionality in free space and near the head model. The antenna is fabricated on cost-effective Rogers RT5880 and RO4350B substrate, and the optimized dimension of the antenna is 50 x 40 x 8.66 mm3. The measured results show that the antenna has a fractional bandwidth of 79.20% (1.37-3.16 GHz), 93% radiation efficiency, 98% high fidelity factor, 6.67 dBi gain, and adequate field penetration in the head tissue with a maximum of 0.0018 W/kg specific absorption rate. In addition, a 3D realistic tissue-mimicking head phantom is fabricated and measured to verify the performance of the antenna. Later, a nine-antenna array-based microwave brain imaging (MBI) system is implemented and investigated by using phantom model. After that, the scattering parameters are collected, analyzed, and then processed by the Iteratively Corrected delay-multiply-and-sum algorithm to detect and reconstruct the brain tumor images. The imaging results demonstrated that the implemented MBI system can successfully detect the target benign and malignant tumors with their locations inside the brain. 2022, The Author(s).This research work is supported by the Universiti Kebangsaan Malaysia (UKM) research Grant DIP-2020-009.Scopu