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Muhd-Yassin S.Z.,Telekom Malaysia Research and Development | Khairul Anuar M.S.,Telekom Malaysia Research and Development | Zulkifli M.I.,Telekom Malaysia Research and Development | Harun S.W.,University of Malaya | And 2 more authors.
Optik | Year: 2012

An efficient erbium/ytterbium co-doped fiber amplifier (EYDFA) is demonstrated by using a dual-stage partial double pass structure with a band pass filter (BPF). The amplifier achieves the maximum small signal gain of 56 dB and the corresponding noise figure of 4.66 dB at 1536 nm with an input signal power and total pump power of -50 dBm and 140 mW, respectively. Compared with a conventional single-stage amplifier, the maximum gain enhancement of 16.99 dB is obtained at 1544 nm with the corresponding noise figure is improved by 2 dB. The proposed amplifier structure only uses a single pump source with a partial double pass scheme to provide a high gain and dual-stage structure to provide the low noise figure. © 2012 Elsevier GmbH. All rights reserved.


Salleh M.K.M.,University Technology of MARA | Yahya M.,University Technology of MARA | Awang Z.,Telekom Malaysia Research and Development | Muhamad W.N.W.,Telekom Malaysia Research and Development | And 2 more authors.
2011 IEEE International RF and Microwave Conference, RFM 2011 - Proceedings | Year: 2011

This paper presents experimental results of our study on multi-layer microwave absorbers synthesized using coconut shells as the source of activated carbon. In this investigation, activated carbon with content variation of 0, 10, 15, 20, 25 and 30 wt% were mixed with Flaxane-80 to study the microwave properties of the absorbers. Three- and four-layer microwave absorbers with various carbon contents were fabricated to study their reflection properties. A microwave non-destructive testing (MNDT) set-up was used to evaluate the microwave properties. Samples with 30 wt% carbon composite showed the highest relative permittivity of 17. All the four-layer absorbers fabricated in this work showed excellent performance in absorbing microwave signals, exhibiting respectable wideband performance with bandwidths up to 38%. © 2011 IEEE.


Salleh M.K.M.,University Technology of MARA | Yahya M.,University Technology of MARA | Awang Z.,Telekom Malaysia Research and Development | Muhamad W.N.W.,Telekom Malaysia Research and Development | And 2 more authors.
2011 IEEE International RF and Microwave Conference, RFM 2011 - Proceedings | Year: 2011

This paper presents results of a study on multi-layer binomial radar absorbers constructed from rubber latex using coconut shells as fillers. The microwave properties of the absorbers were measured using a microwave non-destructive testing (MNDT) technique. The performance of single layer, two-layer and three-layer absorbers were simulated using a commercial 3D electromagnetic simulator. Single layer and two-layer absorbers have bandwidths of 11% and 8% respectively, while the three-layer absorber exhibited the widest bandwidth of 85%. The effect of carbon content and the absorber thickness has been studied and show that increasing absorber thickness and carbon content in the samples shifted the reflection frequency while the bandwidth remained. © 2011 IEEE.


Ashraf Q.M.,Telekom Malaysia Research and Development | Habaebi M.H.,International Islamic University Malaysia | Islam M.R.,International Islamic University Malaysia
IEEE Access | Year: 2016

Recent research on Internet of Things (IoT) has focused on the adaptation of the autonomic computing paradigm to make IoT self-sufficient. Service arbitration is one aspect which can greatly benefit from the adoption of the autonomic theory. Instead of allowing all deployed devices to be active, only a selected set of devices can be utilized to provide a particular service. This paper proposes a dynamic service arbitration scheme for this purpose. The approach for the service arbitration scheme is based on the technique for order preference by similarity to ideal solution (TOPSIS) algorithm. This method supplements existing autonomic frameworks with the aim to minimize user intervention as well as imparting self-configuration in the system. The analysis through TOPSIS can be extended to any number of permutations and combinations of alternatives and system policies. © 2013 IEEE.


Salleh M.K.,Telekom Malaysia Research and Development | Yahya M.,Telekom Malaysia Research and Development | Awang Z.,University Technology of MARA | Muhamad W.N.W.,University Technology of MARA | And 2 more authors.
RFM 2013 - 2013 IEEE International RF and Microwave Conference, Proceedings | Year: 2013

This paper presents the use of Chebychev transformer in the design of multi-layer microwave absorbers constructed of coconut shells. The two, three and four multi-layer absorbers were modelled based on measured permittivity. The permittivity were obtained using microwave non-destructive testing (MNDT) from previous experiment. Then the permittivity of each layer was calculated using Chebychev multi-section transformer to provide a proper transition impedance. These microwave absorbers were modelled and simulated in MATLAB. The simulations were carried out from 1 GHz to 15 GHz to analyse the absorbers performance. The two-layer absorbers showed the multiple resonant frequencies. The permittivity of back layer influences the resonant frequency. A higher permittivity reduces the resonant frequency to a lower value. The two and three-layer absorbers showed an excellent bandwidth up to 110% and 120% respectively. The bandwidth can be improved by adding more layers to provide a smooth transition impedance between layers. © 2013 IEEE.


Fikry A.,University Technology of MARA | Hussein Z.,University Technology of MARA | Yusob R.,Telekom Malaysia Research and Development
BEIAC 2013 - 2013 IEEE Business Engineering and Industrial Applications Colloquium | Year: 2013

This study aims to diagnose the significant differences between the Malaysian demographic profile and intention to adopt healthcare services in digital home. By using two stage experiment involving 105 respondents who resides in Malacca, Kuala Lumpur and Selangor has been selected for this study, 105 questionnaires were distributed to respondents before and after the exposure to healthcare services materials (slides, bunting and pamphlet). The results of the study revealed that there is a significant difference between educational level and intention to adopt healthcare services in digital home. Thus, it is suggested that educational level should be given some consideration in future research efforts. The research and practical implications of these results are discussed and opportunities for future research are provided. © 2013 IEEE.


Salleh M.K.M.,Telekom Malaysia Research and Development | Yahya M.,Telekom Malaysia Research and Development | Awang Z.,University Technology of MARA | Muhamad W.N.W.,University Technology of MARA | And 2 more authors.
IEEE Region 10 Annual International Conference, Proceedings/TENCON | Year: 2011

This paper presents a study of single layer radar absorbing material made using coconut shell-based activated carbon. Flaxane-80 was used as binder and was mixed to give 10 wt%, 15 wt%, 20 wt% and 25 wt% variation of activated carbon obtained from coconut shell to study the microwave properties of the absorber material. An industry standard electromagnetic simulator was used to predict the absorber behaviour, while microwave non-destructive testing (MNDT) technique was used to measure microwave properties and reflection characteristics of the samples. The relative permittivity of 25 wt% carbon sample was found to be the highest with a value of 12. The sample also has the highest tan δ of 0.4. The thicknesses of absorbers made of 25 wt% carbon were varied at 3.2 mm, 6.4 mm, 9.6 mm and 13.8 mm to determine the reflection characteristics. The 6.4 mm sample was found to offer minimum reflection at 9.6 GHz with -22 dB reflection loss. Sample 9.6 mm has a minimum reflection loss of -17dB at 11.3 GHz. The results of this study offer great opportunities for RF application seeking for low cost and light-weight radar absorber material using coconut-shell. © 2011 IEEE.

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