UniversitiTeknikal Malaysia Melaka eM

Melaka, Malaysia

UniversitiTeknikal Malaysia Melaka eM

Melaka, Malaysia
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Abu M.,UniversitiTeknikal Malaysia Melaka eM | Md Ali S.A.,UniversitiTeknikal Malaysia Melaka eM | Mohamad N.R.,UniversitiTeknikal Malaysia Melaka eM | Muhamad M.,UniversitiTeknikal Malaysia Melaka eM
Indonesian Journal of Electrical Engineering and Computer Science | Year: 2017

Flexible dual band dipole antenna incorporates with Electromagnetic Band Gap (EBG) to improve the well-known low profile characteristics of dipole antenna. The antenna operates at 2.45 GHz and 5.8 GHz which is printed on Fast film with 0.13 mm thickness. While the EBG is designed at 5.8 GHz by using Arlon AD350 with 1.016 mm thickness. EBG works as a ground plane for the antenna and helps by improving the realized gainandradiation pattern. Besides, EBG also act as a filter as the resonant frequency of the antenna is close to the EBG band gap. The 2.45 GHz of is eliminated while the performances of antenna at 5.8 GHz is improved. Thus the realized gain is increased up to 6.86 dB and the back lobes are clearly reduced. The designs of dipole antenna with EBG application such as Wifi and others on-body communication devices. © 2017 Institute of Advanced Engineering and Science. All rights reserved.

Hussein S.A.,University of Baghdad | Tahir A.S.M.,UniversitiTeknikal Malaysia Melaka eM
ARPN Journal of Engineering and Applied Sciences | Year: 2017

The amorphous phase which associated the joining of aluminium-to-steel via friction stir welding was investigated. AA5083, AA6061 and zinc coated steel were welded together by a single pass friction stir welding. Heat cycle measurement and scanning electron microscopy were conducted to investigate the effect of using different welding parameter levels on the amorphous phase and intermetallic compound formations. Using of 2000 rpm with 20 mm/min as rotational and welding speeds, respectively, resulted in a long heat cycle. Such long heat cycle could eliminate the amorphous phase and promote thick intermetallic compounds, especially at the AA5083 to steel interface. However, when welding speed was increased, 40 mm/min, a shorter heat cycle was produced, and the amorphous phase was observed. Very high welding speed (300 mm/min) resulted in very short heat cycle with no obvious amorphous phase and very small amount of intermetallic compound at the aluminium-to-steel interface. The formation process of the amorphous phase is schematically explained in this study. © 2006-2017 Asian Research Publishing Network (ARPN). All rights reserved.

Zobilah A.M.,UniversitiTeknikal Malaysia Melaka eM | Zakaria Z.,UniversitiTeknikal Malaysia Melaka eM | Shairi N.A.,UniversitiTeknikal Malaysia Melaka eM
IET Microwaves, Antennas and Propagation | Year: 2017

A selectable multiband isolation of single pole double throw (SPDT) switch with switchable transmission line stub resonators for applications of WiMAX and LTE in 2.3 and 3.5 GHz bands is presented. Two SPDT switches are presented. (Design 2) either allows selecting only one band while unselecting the other or selecting both of them. However, (Design 1) does not allow so. The transmission line stub resonator used in this design is an open stub resonator with quarter wave of the electrical length. By using a simple mathematical model, the theory of the transmission line stub resonator was discussed where it can be cascaded and resonated at centre frequencies of 2.3 and 3.5 GHz. Moreover, the cascaded transmission line stub resonators can be reconfigured between all-pass and band-stop responses using discrete PIN diodes. The key advantage of the proposed SPDT with switchable transmission line stub resonators is a multiband high isolation with a minimum number of PIN diodes. Therefore, the simulated and measured results showed the followings: <3 dB of insertion loss, > 10 dB of return loss and > 30 dB of multiband isolation in 2.3 and 3.5 GHz bands. © The Institution of Engineering and Technology.

Zahari M.K.,UniversitiTeknikal Malaysia Melaka eM | Ahmad B.H.,UniversitiTeknikal Malaysia Melaka eM | Shairi N.A.,UniversitiTeknikal Malaysia Melaka eM | Wong P.W.,UniversitiTeknologiPetronas UTP
2011 IEEE International RF and Microwave Conference, RFM 2011 - Proceedings | Year: 2011

This paper demonstrates a reconfigurable matched bandstop filter. The filter is based on a lossy allpass network. The lossy allpass network demonstrates the concept and design of perfectly matched bandstop response with a perfect matched at all frequencies. The filter is based on the half-wavelength over (λ/2) resonator with gap coupling, parallel with an allpass nominally-90°-phase-shift element, which can be optimized to achieve high Q-factor. The reconfigurable matched bandstop filter can be realized by using PIN diodes as a switching element. This filter provides two state of operation under two conditions. The first condition is that the filter will produce allpass response when the PIN diodes are turned 'ON'. The second condition is that the filter will produce bandstop response when the PIN diodes are turned 'OFF'. Theoretical analysis together with experimental results is presented in this paper. © 2011 IEEE.

Hadi M.H.A.,UniversitiTeknikal Malaysia Melaka eM | Ahmad B.H.,UniversitiTeknikal Malaysia Melaka eM | Shairi N.A.,UniversitiTeknikal Malaysia Melaka eM | Wen Wong P.,Petronas University of Technology
IEEE Symposium on Wireless Technology and Applications, ISWTA | Year: 2013

This paper investigates the effect of a discrete PIN diode on Defected Ground Structure (DGS) where the different resonant frequency between ON and OFF state of the PIN diode is observed. Analytical modeling is determined and analyzed based on equivalent circuit of PIN diode and DGS. Then, a circuit simulation is performed using simulation software with different value of inductance and capacitance of DGS during ON and OFF state of the PIN diode. As a result, the resonant frequency of the PIN diode on the DGS shifted to higher frequency during ON state and shifted to lower frequency during OFF state. Besides, a larger value of inductance with a smaller value of capacitance of DGS will produce a larger range of resonant frequency between ON and OFF state and vice versa. © 2013 IEEE.

Saipullah K.M.,UniversitiTeknikal Malaysia Melaka eM | Ismail N.A.,UniversitiTeknikal Malaysia Melaka eM
2012 IEEE Asia-Pacific Conference on Applied Electromagnetics, APACE 2012 - Proceedings | Year: 2012

Spectral classification for hyperspectral image is a challenging job because of the number of spectral in a hyperspectral image and high dimensional spectral. In this paper, we proposed a method to enhance the spectral classification using the Adaboost for hyperspectral image analysis. By applying the Adaboost algorithm to the classifier, the classification can be executed iteratively by giving weight to the spectral data, thus will reduce the classification error rate. The Adaboost is implemented to spectral angle mapper (SAM), Euclidean distance (ED), and city block distance (CD). From the experimental results, the Adaboost increases the average classification accuracy of 2000 spectral up to 99.63% using the CD. Overall, Adaboost increases the average classification accuracy of ED, CD, and SAM by 2.54%, 1.95%, and 1.67%. © 2012 IEEE.

Azam M.A.,UniversitiTeknikal Malaysia Melaka eM | Dorah N.,UniversitiTeknikal Malaysia Melaka eM | Seman R.N.A.R.,UniversitiTeknikal Malaysia Melaka eM | Manaf N.S.A.,UniversitiTeknikal Malaysia Melaka eM | Kudin T.I.T.,University Technology of MARA
Materials Technology | Year: 2015

A conventional but simple fabrication technique of activated carbon/graphene (AC/G) supercapacitor electrode will be presented in this work. The AC/G electrode was prepared using slurry technique from the mixture of AC and graphene powders, polytetrafluoroethylene as binder and N-methylpyrrolidone as solvent. The AC/G electrode was dried at 120°C in vacuum oven for 6 h followed by immersing in 1M lithium hexafluorophosphate electrolyte for another 6 h. The specific gravimetric capacitance of the electrode was calculated to be 19·45 F g-1 using cyclic voltammetry at a scan rate of 1 mV s-1. Electrochemical behaviour including charge discharge and impedance characteristics confirmed the electrode's ability as a possible active material for use in carbon based supercapacitor. © 2015 W. S. Maney & Son Ltd.

Omar R.,UniversitiTeknikal Malaysia Melaka eM | Sulaiman M.,UniversitiTeknikal Malaysia Melaka eM
International Journal of Applied Engineering Research | Year: 2015

Multilevel inverter using cascaded H-bridge inverter with separated dc source (SDCSs) are introduced in single phase structure. The output voltage is the sum of the output of each H-bridge cell. The output voltage waveform is ideal with suitable switching angle estimation to produce required fundamental voltage. This paper presents the simulation of 5-level cascaded H-bridge multilevel inverter with selecting different switching angle based on Newton-Raphson method is used for angle optimization. Simulation work is done by using MATLAB/Simulink software. © Research India Publications.

Azam M.A.,UniversitiTeknikal Malaysia Melaka eM | Nawi Z.M.,UniversitiTeknikal Malaysia Melaka eM | Azren N.M.,UniversitiTeknikal Malaysia Melaka eM | Zulkapli N.N.,UniversitiTeknikal Malaysia Melaka eM
Materials Technology | Year: 2015

The iron catalyst nanoparticles were prepared on silicon wafers by solution process, which first spins coat the solution of iron (III) nitrate nonahydrate and colloidal solution, and then are heated to obtain the formation of iron nanoparticles. The effects of different spin speed and heat treatment parameters during the solution process were investigated. As a result, the smallest thickness of the Fe catalyst thin films is 78 nm, and the smallest Fe catalyst nanoparticles, i.e. 9·67 nm, were obtained at the highest spin speed of 8000 rev min-1 and 500°C. The uniformity of the thin films was also found to increase with increasing spin speed. The particle and thickness analysis was performed by means of field emission scanning electron microscopy. © 2015 W. S. Maney & Son Ltd.

Zakaria Z.,UniversitiTeknikal Malaysia Melaka eM | Sabah A.,UniversitiTeknikal Malaysia Melaka eM | Sam W.Y.,UniversitiTeknikal Malaysia Melaka eM
ISBEIA 2012 - IEEE Symposium on Business, Engineering and Industrial Applications | Year: 2012

This paper presents a low-loss of coaxial cavity bandpass filter with post-manufacturing tuning capabilities. A systematic filter development using the lowpass prototype as a starting point to produce 4th degreeChebyshevbandpass response is demonstrated. The coaxial cavity filter based upon TEM mode of propagation has the center frequency of 2.5 GHz and bandwidth of 168MHz. The insertion loss of 0.15 dB insertion loss and return loss better than 15 dB areobtained particularly in the passband. This type of microwave filter would be useful in any microwave systems where the low insertion loss and high selectivity are crucial, such as in a base station, radar and satellite transceivers. Copyright © 2012 IEEE.

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