This paper is to study the dielectric properties and microwave absorption of rice husk ash/polyester (RHAP) composites. The RHAP composites prepared with different weight ratio (40-80 wt. %) of rice husk ash (RHA) loading into polyester was fabricated. A rectangular waveguide transmission line method was used to measure the dielectric properties of the RHAP composites. The RHAP samples were designed and simulated with different thickness and percentage of RHA loading by using Computer Simulation Technology Microwave Studio (CST-MWS) software. The materials, their dielectrics properties measurement and microwave absorption result over 12.4-18 GHz (Ku-Band) frequency range are discussed. The dielectric properties of composites increase with increasing loading the RA wt%. The RHAP sample with different thickness was investigated in Ku-Band. The microwave absorption was up to 99.84 %, using 80 % loading of RHA with thickness 15 mm at 13.81 GHz, and showing the RHAP composites is applicable as microwave absorber.

The electromagnetic interference (EMI) absorbing materials in various microwave frequency were required most now due to increasing demand of electromagnetic compatibility (EMC) for electronic devices with various electromagnetic environments. So, absorber materials are needed in RF/Microwave to eliminate and absorb electromagnetic energy. Absorbers can be used to create a free space environment in anechoic chamber. This work describes the performances which are the reflection loss and absorption for composite of sugarcane bagasse mixed with rubber tire dust microwave absorber in Ku Band frequency (12.4-18 GHz). The parameters such as dielectric properties, reflection coefficient (S 11 ) and transmission coefficient (S 21 ) were investigated. The main objectives of this research are to design and develop a microwave absorber with new green materials which are sugarcane bagasse and other waste material such as rubber tire dust. These agricultural wastes can help save the nature and the fabrication cost of microwave absorber can be reduced. Based on the result, it proved that the sugarcane bagasse-rubber tire dust can be a good alternative material to be used as microwave absorber and can operate in frequency range between 12.4 and 18 GHz.

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This project is to present the transient recovery voltage on circuit breaker in power system network. The transient recovery voltage is a characteristic in power system and will found just only microsecond in the power system network. The objective of this project is to simulate and analysis the transient recovery voltage on circuit breaker. It is to investigate the transient recovery voltage before and after the circuit breaker interrupts and also the transient recovery voltage under the fault. The method used in this project is by simulating the circuit using the PSCAD software. This software will simulate the circuit model and collect some data to give more understanding about transient recovery voltage. This project will continue by analyzing the result based on the data collected. The simulation results are same with the expected results and thus, it show that the simulation results are correct and pre theoretical. In conclusion, the transient recovery voltage affects the breaking capacity of the circuit breaker operation and also affects the power system network operation.

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