Mohd Asri Jusoh

Circular Polarized Patch Antenna for 1.8 and 2.4 GHz Applications

This paper presented a patch circular polarized antenna for GSM technology at 1.8 GHz and WLAN technology at 2.4 GHz. A traveling wave microstrip array antenna consisting of square truncated patch operated as circular polarized has been designed, fabricated and measured. The inter element spacing; length and width of the square and circular patches of the array antenna were optimized by successive simulations using the CST software. This antenna had radiated at 1.8 and 2.4 GHz of resonant frequency with −38.563 and −24.967 dB of return loss respectively. The axial ratio for RHS circular polarized is 0.95 < 3 dB at 2.4 GHz.

Performance of Sugarcane Bagasse and Rubber Tire Dust Microwave Absorber in Ku Band Frequency

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 (S11) and transmission coefficient (S21) 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.

Composites Based on Rice Husk Ash/Polyester for Use as Microwave Absorber

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.

Efficient Power Generation for Smart Homes Based Titanium Dioxide (TiO2)

Smart home uses a combination of the renewable energy power resources, the use of power generation from solar cells based on titanium dioxide (TiO2) which acts as the only type which produces an efficient solar cell power to obtain the electricity to recharge the standby storage device from the sunlight. The thin film of Titanium dioxide is synthesized by the sol-gel spin coating techniques at 2000 rpm on the glass. The films have a constant thickness of ~240nm. The annealing process consists of 150°C, 250°C and 350°C. The study of the absorbance and the wavelength values are important. At this condition, for the solar cell, the wavelength is around ~280nm to ~330nm. As the temperature of annealing increases the higher absorbance would be produced. The refractive index of TiO2 film is estimated at different annealing temperatures and it increases with the increasing of the annealing temperature. The application is suitable to smart home design. The dynamic output voltage obtained from the solar cells is interfaced with other circuitry such as inverters and interface charging circuit in order to inject the generated power into the standby storage device. The calculated result of this application is efficient to reduce the electrical bill by almost 30% of its original value.

Investigation of Rice Husk/CNTs Composites Performance in Microwave Properties

This paper is to study the performance of rice husk and carbon-nanotubes nanotubes (RH-CNTs) composite material as a microwave absorber. The rice husk (RH) is a lossy material that contains dielectric properties which suitable used as microwave absorber. The dielectric properties are playing a main role in microwave absorption of any material. The dielectric properties of materials were measured using an Agilent dielectric probe. The microwave absorption performance of rice husk and CNTs composites was investigated by using rectangular waveguide transmission line in simulation. The microwave absorbers were designed and simulated using the Computer Simulation Technology Microwave studio software (CST-MWS). The ability of microwave absorption between rice husk and RH-CNTs was compared in 8.2–12.4 GHz. The microwave absorption with different thickness of RH-CNTs samples was investigated. The results show that the RH-CNTs composites have a better ability of microwave absorption compared than pure rice husk.

Two Small Antenna Designs for Ultra-Wideband Wireless Systems

This chapter focuses on designing small antennas used by Ultra Wideband (UWB) wireless systems. The study has been taken from the conventional rectangular manuscript patch antenna to miniaturize the size of used antenna to be more suitable for future 5G system applications. These applications are dealing with high data transmission rates over a very large spread spectrum frequency (3.1–10.6 GHz), so that, many challenges are provided in the antenna design. The main objective of this research is to design, and analyze two small manuscript patch antennas to satisfy UWB technology requirements. Several techniques were used to optimize the UWB bandwidth performance such as radiator dimensions, planar ground plane, and unprinted gaps between ground plane and radiators. Therefore, this work introduces two designs of microstrip-fed, small, and low profile which are called ax-shaped and socket-shaped patch antennas. It has been demonstrated numerically that the proposed antennas are suitable for UWB systems. They can provide satisfactory frequency domain performance (less than −10 dB return loss), including ultra-wide bandwidth with nearly omni-directional radiation patterns, and relatively good current density over the radiator parts of the proposed antenna designs.

Strength Pareto Evolutionary Algorithm 2 in Optimizing Ninth Order Multiple Feedback Chebyshev Low Pass Filter

Circuit design optimization has become a common research to reduce the manpower and computational resource required for circuit design industries. Despite the involvement of multiple design objectives, higher order circuit designs are often more complicated and difficult to be optimized using conventional circuit tuning method. This paper proposed Strength Pareto Evolutionary Algorithm 2 (SPEA2) to optimize a ninth order multiple feedback Chebyshev low pass filter. This research aims to search the best trade-off solution that could minimize the passband ripple, maximize the gain and achieve the targeted cutoff frequency. The NGSPICE circuit simulator is interacted with SPEA2 algorithm to perform the circuit optimization. The results obtained show the reliability of the algorithm in achieving the required optimization objectives.

CPW Circular Patch Antenna for Ground Penetrating Radar Applications

A Co-planar Waveguide (CPW) Circular patch antenna for Ground Penetrating Radar (GPR) applications is presented in this paper. The antenna is designed on Rogers substrate RO 3010 with dielectric constant of 10.2 with a thickness, h = 1.22 mm and tangent loss = 0.0022 operates from 1.1 to 5.5 GHz with the overall size is 140 mm × 140 mm. CPW was used as an input method for the antenna with 50 Ω impedance matching and Computer Simulation Technology (CST 2013) has been used as simulation tools to observe the antenna performances. In order to produce antenna with high gain performance, a reflector is located at the back of the antenna. The antenna parameters such as simulated return loss, gain, radiation pattern and current distribution of the antenna is presented.

Comparison of Operational Losses under Rated and Nonlinear Loads for 2 kVA Three-Phase Three Legged Dry Type Power Transformer

This paper produces experimental results comparing operational loss of a power transformer under rated and nonlinear load. A 2kVA three phase three legged dry type power transformer is primarily designed for rated loss; however it is operated with a nonlinear load. Three phase rectifier with variable capacitors is the selected current harmonic source and the distortion at current waveform is controlled by the capacitance values. Initially the operation losses under rated load is measured and then followed with measurement with nonlinear load. At the end of this paper, both type of operation losses is compared and differentiated.

Study on Dielectric and Magnetic Properties of MWCNTs/Polyester Composites

This paper is to study the dielectric properties, magnetic properties, and dielectric conductivity of Multi-walled carbon nanotubes (MWCNTs) and polyester (PE) composites. The composites with different amount of MWCNTs (5-15%) have been studied in the Ku-Band range (12.4-18 GHz). The rectangular waveguide (WR-62) was used to measure the dielectric properties and magnetic properties of the samples. The results show the dielectric properties and conductivity of MWCNTs/PE composites is increasing with the MWCNTs filler increases. The real part of dielectric properties values increase from 5.5 to 26.6 with increasing the MWCNTs loading from 5 % to 15 %. The increasing of MWCNTs filler in the MWCNTs/PE composites does not effects on magnetic properties, the real part and imaginary part of magnetic properties are approximate to 1 and 0. The highest conductivity of 15 % MWCNTs loading is reach to 11.02 (S/m) at 18 GHz. Keywords: composites, dielectric properties, magnetic properties, conductivity