Time filter

Source Type

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.

Ramli M.H.,UniversitiTeknikal Malaysia Melaka eM | Aziz M.Z.A.A.,UniversitiTeknikal Malaysia Melaka eM | Othman M.A.,UniversitiTeknikal Malaysia Melaka eM | Dahalan A.H.,University Technical Malaysia Melaka
2016 26th International Conference Radioelektronika, RADIOELEKTRONIKA 2016 | Year: 2016

A multiband planar printed monopole antenna with Minkowski and Lollipop defected parasitic structure (DPS) for wireless communication system is proposed. The proposed antenna can create and work effectively to covers triband resonance frequencies at 2.4, 3.6 and 5.8 GHz within WLAN/WiMAX range in wireless communication system application. The Minkowski and Lollipop DPS has been place in front of and back of the multiband antenna that easily fed by using a 50 Ω microstrip line. The parametric study has been performed to analyze the best range of DPS from the proposed antenna. The simulated and measured impedance bandwidths for 10 dB return loss at first, second and third operating bands can be seen at (135 and 456) MHz, (380 and 272) MHz and (198 and 283) MHz respectively. The additional DPS helps to improve the return loss, bandwidth, gain, directivity. The simulation and measurement performance are well compared and discussed. © 2016 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.

Md. Shukor M.,UniversitiTeknikal Malaysia Melaka eM | Abd. Aziz M.Z.A.,UniversitiTeknikal Malaysia Melaka eM | Ahmad B.H.,UniversitiTeknikal Malaysia Melaka eM | Suaidi M.K.,UniversitiTeknikal Malaysia Melaka eM | Othman M.A.,UniversitiTeknikal Malaysia Melaka eM
Jurnal Teknologi (Sciences and Engineering) | Year: 2014

This paper presents the antenna designed with radiating structure of 3.5 for dual band applications. This antenna is designed and simulated by using CST Studio Suite software at 2.4 GHz and 5.2 GHz based on standard IEEE 802.11a (5.15 GHz-5.35 GHz) and IEEE 802.11b (2.4 GHz-2.48 GHz) frequency bands. The radiating structure 5 and 3 are designed to radiated at frequency 2.4 GHz and 5.2 GHz respectively. Then, both structures are combined to achieve dual band resonant frequencies. The techniques that have been used to achieve dual band resonant are by designing the 3.5 shaped by using planar and coplanar waveguide (CPW) structures. There are three designs of dual band antenna which are Design A, Design B and Design C. The optimum return loss for 2.4 GHz and 5.2 GHz frequency response are -16.44 dB and -18.78 dB respectively achieved by Design C. The changes on the position of radiating structure 3 will effects the frequency response, return loss and gain of the antenna. © 2014 Penerbit UTM Press. All rights reserved.

Saipullah K.M.,UniversitiTeknikal Malaysia Melaka eM | Ismail N.A.,UniversitiTeknikal Malaysia Melaka eM | Soo Y.,UniversitiTeknikal Malaysia Melaka eM
Proceedings - 2012 IEEE International Conference on Control System, Computing and Engineering, ICCSCE 2012 | Year: 2013

This paper present a new feature extractors called the Fractionalized Principle Magnitude (FPM) that is evaluated in the classification of approved Halal logo with respect to classification accuracy and time consumptions. Feature can be classified into two group; global feature and local feature. In this study, several feature extractors have been compared with the proposed method such as histogram of gradient (HOG), Hu moment, Zernike moment and wavelet co-occurrence histogram (WCH). The experiments are conducted on 50 different approved Halal logos. The result shows that proposed FPM method achieves the highest accuracy with 90.4% whereas HOG, Zernike moment, WCH and Hu moment achieve 75.2%, 64.4%, 47.2% 44.4% of accuracies, respectively. © 2012 IEEE.

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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