This paper presents the development of digital simulator tool for sensitivity analysis of ac contactor with respect to voltage sag characteristics. The simulator tool allows varying of the sag characteristics for the purpose of evaluating the behavior of ac contactor under very worst conditions of voltage sags. Describing voltage sag characteristics by their magnitude and duration only without consideration of other parameters is no longer suitable to fully assess the equipments sensitivity. Therefore, this paper presents the necessity to include the point-on-wave of sag initiation and phase shift of sag to explain the sensitivity of ac contactor during sags. From the simulation results, the ride through capability curve is constructed to identify ac contactor sensitivity levels. The curve has demonstrated a rather complex behavior of the ac contactor. By having a simulator tool, ac contactor analysis can be simulated for any type of configurations without having to perform laboratory experiments.

This paper will introduce the new technique to design new type of microwave absorber. Microwave absorbers are used in anechoic chamber to diminish the unwanted RF signal, so that the measurement obtain have perfect and good results. The basic theories of slot antenna combining with the theory of microwave absorber are used in this paper. As a result of studies, the new design called as the slot radial array design on hollow pyramidal microwave absorber. The design of pyramidal microwave absorber and the slot was introducing in this paper. The simulation process was done by using CST software. The new design of the absorber was measured to make sure it can be compared in terms of the performance. Lastly, the performance of new slot radial array design pyramidal microwave absorber will be analysed by identifying the characteristics performance. The Slot Radial Array proved to be as one of the way to improve the performance.

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Electromagnetic elimination was used to eliminate unwanted radiation that may interface with machinery or affect human health. The use of microwave absorbers has become necessary for an environment with a safe electromagnetic wave level. The objectives of this project are to design a microwave absorber as a modern biomass wall tile and to investigate the absorbing performance of the modern wall tile absorbers with different materials. The absorber was designed with similar shapes and different biomass materials. The concept of modern wall tile had been applied to design the absorbers in terms of their shape and dimension by using biomass materials. Biomass materials such as kenaf and coconut coir were used in the study due to their lightweight and environmental-friendly material behavior. The simulation was done using CST Suite Studio software to predict the preliminary result of the absorbers. The proposed designs of the modern wall tile from the CST simulation are then fabricated while the mixtures of the materials are moulded into a microwave absorber. NRL Arch free space method was used to determine the absorption performance of the modern wall tile absorbers at a frequency range from 1GHz to 12GHz. Both results of the simulation and free space measurement are analyzed and discussed. This study showed that absorber KCA has the best performance among all the absorbers with the absorption of more than -10 dB. The mixture of biomass material with carbon has a great absorption performance compared to the mixture of biomass material without carbon.

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