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This paper will be focuses on the performance analysis of a microstrip patch antenna with two different feeding techniques; microstrip feedline and coaxial feeding technique. The design simulation is done by using CST Microwave Studio software. Comparative analysis of simulated parameters such as return loss, efficiency, VSWR and surface current distribution are also discussed in this paper. From the analysis, it is found that the MPA with coaxial feed configuration obtained better performance of return loss compared to microstrip feedline technique by 22.5% improvement. The MPA with coaxial feed is fabricated and verified by using Vector Network Analyzer to validate the performance in real life environment.

This paper presents the design of parallel coupled line band pass filter with 10 GHz operating frequency that will be used in 5G applications. As 5G application requires big data usage and to cater the applications, the bandwidth of 5G devices need to be wider enough to support it. Thus, to improve the bandwidth performance of the designed filter, patterned ground structure (PGS) technique is implemented into it. The result shows that the bandwidth of the designed filter has been improved from 0.25 GHz to 4.98 GHz when PGS is implemented.

In the past few decade, longhouse communities in the rural area of Sarawak has been experienced the limitation of electricity supplies. Due to geographic of Sarawak, supply electricity to these rural areas from utility grid through transmission lines also will only results in many losses, the initiation of utilize solar as prime sources is favourable solution. The implementation of DC microgrid system for this area will achieved, as the solar PV system is a DC source to generate electrical supply for appliances in longhouse communities. However, the tropical climate and geographical in Sarawak such as the inconsistent solar radiation, changing temperatures, high humidity and heavy rainfall will be the main restrain to implement solar DC microgrid system. Thus, this paper proposes a comprehensive study about the voltage distribution of DC microgrid configuration in order to investigate system the reliability and efficiency. The configuration of DC micro-grid model has been designed using MATLAB Simulink and an experimental presenting the Simulink also has been developed for validation purposes. The obtained simulation and experimental results confirm that the proposed configuration of the ring system with multiple-sources is more reliable and efficient than radial system with multiple-source configuration in terms of DC voltage distribution at different buses. Thus, the proposed configuration is more reliable according to voltage distribution at each buses.

In the past few years, the prime focus of supplying electricity to the longhouse communities in the rural areas of Sarawak has been initiated based on the utilization of a single-source microgrid configuration. The existing AC power supply-based solar photovoltaic (PV) systems in these areas pose many problems, mainly owing to the stages of conversion, energy losses, and the quality of power transfer. As the solar PV system is a DC source and most of the appliances in longhouse communities could be operated using DC source, an opportunity to design a microgrid with high reliability and efficiency would be achieved by the implementation of an optimal DC microgrid configuration. With this aim, the paper proposes a multiple-source DC microgrid configuration for the longhouse communities in Sarawak. Initially, a framework has been developed to design simulation models for both microgrid configurations (single and multiple sources) using MATLAB Simulink. The configuration of each system consists of a solar PV and energy storage to form a standalone microgrid. Due to the change in system configuration of DC microgrid, in the modeling approach, the standard power flow equations are modified to include solely the DC parameters. To validate the proposed configuration with the associated modeling approach in terms of the power flow reliability, system efficiency, and power-voltage curve, an experimental setup representing the Simulink model has been designed for each standalone microgrid configuration. The configurations have been assessed in the same location with different daily weather conditions. The obtained simulation and experimental results confirm that the proposed configuration of multiple sources is more reliable and efficient than the existing single-source configuration.

This paper focus on the employment of partial coherent beam (PCB) in free space optical communication to reduce the flux variance effects in the system. The implementation of PCB in the free space optical system is significantly able to reduce the flux variance effect. The reduction of the flux variance effect by using PCB in free space optical communication by using Gamma-Gamma distribution is presented in this paper. The analysis result shows that the FSO system with PCB have an improved in performance compares with FSO system without PCB implemented on it as it capable to decrease the flux variance and scintillation index. This can help FSO system to encounter with severe turbulence effect for optimum operation.

This paper focus on performance of code Zero Correlation-Correlation (ZCC) in free space optical communication. The ZCC code has a superior characteristic which eliminate the overlapping code between any users. Due to this high class characteristic, the code improves the performance of the conventional code in free space optical environment. In this paper the analysis performance of bit error rate is considering the avalanche (APD) noise, thermal noise and multiuser interference. The result shows that ZCC code improve the performance of conventional code in term of number of users, power received and data bit rate.

This paper focuses the rain effect over FSO link medium in Malaysia environment. In this work, a rain data samples that collected from Malaysian Meteorological Department (MMD) to determine the scattering coefficient, atmospheric attenuation and total attenuation. From the analysis, the precipitation rate give different impact over FSO link which can cause the attenuation and bit error rate increase. The results also show the comparison parameter for optimal geometrical loss such as beam divergence, aperture size and receiver sensitivity.

Aiming to achieve 3-dB coupling, operating in fifth generation (5G) technologies, this paper introduces a new design of tight coupling coupler that will be operated in 5G technologies. Two stubs and two slots have been implemented into the 3-dB coupler design in order to achieve impedance matching between the ports and to give better coupling performances, respectively. Moreover, a study on the stubs’ and slots’ effects towards the S31 of the 3-dB coupler has also been presented in this paper. The proposed coupler is designed on Rogers RO4003C substrate. The simulation results and the analytical study on the stubs and slots implementation show that both stubs and slots affect the performance of the coupling coefficient.

Polymeric materials are widely used in power apparatus as electrical insulation especially as high voltage cable insulation. Meanwhile, partial discharge (PD) has always been a predecessor to major faults and problem in this field. Recent works showed that combination of natural rubber and polyethylene produces a good match of composite for electrical insulation. In this paper, blends of natural rubber, polymeric-based material of linear-low density polyethylene (LLDPE), nano-sized fillers of silica (SiO2) and titania (TiO2) were prepared by extrusion machine and moulding process. PD tests were carried out on each sample based on CIGRE Method II technique for 3 hours of ageing time. DAQ software was used as a tool to analyse the PD data, which measures PD pulse magnitude and number of PD occurrence. In addition, SEM images and percentage of element from EDX of the samples were taken before and after experiencing high voltage stress. The results revealed that there is a correlation between amount of filler and discharge activities.

Free space optical communication fsoc is vulnerable with fluctuating atmospheric. This paper focus analyzes the finding of new technique dual diffuser modulation (ddm) to mitigate the atmospheric turbulence effect. The performance of fsoc under the presence of atmospheric turbulence will cause the laser beam keens to (a) beam wander, (b) beam spreading and (c) scintillation. The most deteriorate the fsoc is scintillation where it affected the wavefront cause to fluctuating signal and ultimately receiver can turn into saturate or loss signal. Ddm approach enhances the detecting bit ‘1’ and bit ‘0’ and improves the power received to combat with turbulence effect. The performance focus on signal-to-noise (snr) and bit error rate (ber) where the numerical result shows that the ddm technique able to improves the range where estimated approximately 40% improvement under weak turbulence and 80% under strong turbulence.