Mohd Azlishah Othman

Firefly algorithm for path optimization in PCB holes drilling process

In PCB holes drilling process, the time taken for a task completion heavily rely on the distance travels by the drill bit of the CNC machine. In order to minimize the distance traveled by the drill bit, Firefly Algorithm can be used. The proposed model applies Firefly Algorithm to search for the optimized path in PCB holes drilling process. Each agents position represented a possible path that can be taken by the drill bit. The fitness of the agent is inversely proportional to the distance of the path where the shorter the distance, the better the fitness of an agent. Then, the agents compare their fitness with each other. Agent will try to improve its fitness by moving closer towards other agent with better fitness. The process repeated until maximum iteration achieved. Performance of the proposed model is compared with other literatures using a standard case study.

Investigation of dual and triple meander slot to microstrip patch antenna

A dual and triple microstrip meander slot antenna is presented for Wireless Local Area Network (WLAN) application. The antenna also has the potential to be used as the receiving antenna in an energy harvesting system. The proposed antenna comprises a rectangular microstrip patch element embedded with meander slots. The parametric study is performed to investigate the characteristic of microstrip patch antenna with double meandered slots compared to the same microstrip patch antenna with triple meandered slots. Microstrip patch antenna with dual meander slot can achieve return loss until -24.54dB. However the gain of the antenna, 1.46 dBi is lower than microstrip patch antenna with triple meander slot which is 4.28 dBi. Other antenna parameters are also investigated such as bandwidth, radiation patterns and directivity have been observed and simulated. Measurement results are also recorded in this paper.

Design of wideband antenna for RF energy harvesting system

This paper studies a wideband antenna of ice-cream cone structure and it is integrated with a rectifying circuit which has the potential to be used for RF energy harvesting system. The antenna is designed by using CST Studio Suite 2011 and fabricated on a double sided FR-4 printed circuit board using an etching technique. A single stage rectifying circuit is designed, simulated, fabricated and measured in this work. The design and simulation process was done by using Agilent Advanced Design System (ADS) 2011. Simulation and measurement were carried out for various input power levels at the specified frequency band. An experimental test has been conducted by varying the load, R of the rectifying circuit. For an equivalent incident signal of 20 dB, the system managed to produce 0.09V with load of 20kΩ. This voltage can be used to power low power sensors in sensor networks ultimately in place of batteries.

Tri-band Minkowski Island patch antenna with complementary split ring resonator at the ground plane

The Minkoski Island patch antenna with complementary split ring resonator at the ground plane are proposed in this work. At the first stage, the normal square patch antennas mainly designed. Then, the Minkowski patch antenna was designed using 1st iteration technique and 2nd iteration technique. The Minkowski fractal shape slot was embedded in the center of the patch to form a Minkowski Island patch antenna. The next step is to apply the partial ground technique and embed the split ring resonator at the ground plane. This antenna was operating in tri-band frequency that is at 2.400 GHz, 3.500 GHz and 5.200 GHz with a return loss of - 11.868 dB, - 13.554 dB and - 18.112 dB respectively. The gain measured of this antenna is 1.286 dB, 1.410 dB and 3.945 dB.

Electrical Conductivity Characteristic of TiO2 Nanowires From Hydrothermal Method

One dimensional nanostructures of titanium dioxide (TiO2) were synthesized via hydrothermal method by mixing TiO2 as precursor in aqueous solution of NaOH as solvent. Then, heat and washing treatment was applied. Thus obtained wires had diameter ~15nm. TiO2 nanowires will be used as a network in solar cell such dye-sensitized solar cell in order to improve the performance of electron movement in the device. To improve the performance of electron movement, the characteristics of TiO2 nanowires have been analyses using field emission scanning electron microscopy (FESEM) analysis, x-ray diffractometer (XRD) analysis and brunauer emmett teller (BET) analysis. Finally, electrical conductivity of TiO2 nanowires was determined by measuring the resistance of the TiO2 nanowires paste on microscope glass.

Design of Gaas E-phemt low noise amplifier for WLAN application

This paper describes the design of low noise amplifier using enhancement mode technology for WLAN front-end applications. Typical LNA designed for the IEEE802.1a standard is required to operate with low noise, high gain and exhibit low noise figure. The design uses feedback, and balanced topology to enhance the performance and to achieve the design goal. The LNA is designed operate at 2.4 GHz, noise figure (NF)<; 2dB, gain>;10 dB and with S11 and S22 <;-10 dB. With the voltage supply at 5 V, the total current consumptions for the LNA is 60 Ma.

Advanced Computer and Communication Engineering Technology

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An analysis of low pass filter using bowtie Defected Ground Structure (DGS) at 10 GHz for radar application

price are net prices, subject to local VAT. Prices indicated with * include VAT for books; the €(D) includes 7% for Germany, the €(A) includes 10% for Austria. Prices indicated with ** include VAT for electronic products; 19% for Germany, 20% for Austria. All prices exclusive of carriage charges. Prices and other details are subject to change without notice. All errors and omissions excepted. H.A. Sulaiman, M.A. Othman, M.F.I. Othman, Y.A. Rahim, N.C. Pee (Eds.) Advanced Computer and Communication Engineering Technology

Development of ultra-wideband (UWB) horn antenna using approximation method

This paper describes the design of Low-pass filter using bowtie Defected Ground Structure (DGS). The designing of low-pass filter begins from lumped element in which the filter will be built using capacitors and inductors before converted to open and short circuited stub. The low-pass filter using bowtie Defected Ground Structure (DGS) is required to operate at 10 GHz for radar application. As a comparison, the design of different size and quantity of bowtie Defected Ground Structure (DGS) were analyzed to identify the better performance of the low-pass filter. The design of this filter had been simulated by using schematic and EM Simulation in Agilent Advanced Design System (ADS) software.

A survey on human behavior towards energy efficiency for office worker in malaysia

This paper presents a design of an ultra wide-band (UWB) horn antenna for microwave imaging radar system. The key purpose of the study is to design a horn antenna which is used in medical imaging system. The proposed antenna operates within 3.1-10.6 GHz as it is the band allocated for medical industry usage. The antenna known as a directional antenna which is supported by rectangular waveguide. The horn antenna is purposely chosen to design in order to increase the directivity of the antenna within 15-20 dB and achieve higher gain and wider bandwidth as possible. This horn antenna is capable to produce return loss as minimum as possible. The antenna is designed and simulated using CST Microwave Studio. The simulation results show that the pyramidal horn antenna structure exhibits low VSWR as well as good radiation pattern over 3.1-10.6 GHz frequency band.