Nor Azura Malini Ahmad Hambali
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Preferred name
Nor Azura Malini Ahmad Hambali
Official Name
Nor Azura Malini, Ahmad Hambali
Alternative Name
Hambali, N. A. M. Ahmad
Hambali, N. A. M. A.
Hambali, Nor Azura Malini Ahmad
Idris, N. A.
Hambali, N. Azura M. Ahmad
Main Affiliation
Scopus Author ID
27567626900
Researcher ID
JFK-8606-2023

Research Output

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Remazol orange dye sensitized solar cell

2017-01-03 , Siti Salwa Mat Isa , Muhammad Mahyiddin Ramli , Nor Azura Malini Ahmad Hambali , Muda M.R. , Shahrir Rizal Kasjoo , Muammar Mohamad Isa , Nurul Izza Mohd Nor , Norhawati Ahmad , Nazuhusna Khalid , Nur M. Selamat , Nur Asyikin Mohd Anhar

Water based Remazol Orange was utilized as the dye sensitizer for dye sensitized solar cell. The annealing temperature of TiO2 working electrode was set at 450 °C. The performance of the device was investigated between dye concentrations of 0.25 mM and 2.5 mM at three different immersion times (3, 12 and 24 hours). The adsorption peak of the dye sensitizer was evaluated using UV-Vis-Nir and the device performance was tested using solar cell simulator. The results show that the performance was increased at higher dye concentration and longer immersion time. The best device performance was obtained at 0.2% for dye concentration of 2.5 mM immersed at 24 hours.

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Microwave and electrical properties of SrTiO3 for DRA application

2018-12 , Norhizatol Fashren Muhamad , Rozana Aina Maulat Osman , Mohd Sobri Idris , Mohd Najib Mohd Yasin , Mohd Faizal Jamlos , Nor Azura Malini Ahmad Hambali , Mohd Nazree Derman

Appropriate level of dielectric constant and low dielectric loss are basic requirements for microwave device, especially in dielectric resonator antenna (DRA). In this paper, investigation with experimental studies of SrTiO₃ ceramic fabricated as cylindrical dielectric resonator antennas (CDRAs) was conducted. Ceramic powder was prepared using conventional solid state reaction method. X-ray Diffraction exposes physical properties SrTiO₃ which exhibit cubic structure. The electrical properties such as dielectric constant (εᵣ) and dielectric loss (tan δ) were studied in variation of temperatures and frequencies. At room temperature the dielectric constant SrTiO₃ is about 240. The dielectric loss obtain shows very low loss value roughly below 0.07. The return loss and bandwidth of CDRAs at their respective resonant frequencies are shown in this paper.

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Thermal analysis of LED packaging with single-walled carbon nanotube heat sink

2023 , Chu Kok Keong , Nor Azura Malini Ahmad Hambali , Mohamad Halim Abd. Wahid , H. Mohamad , Norshamsuri Ali @ Hasim

The thermal issue is still the bottleneck of a light emitting diode (LED) system to sustain its operational performance. In this paper, we design, simulated, and analysed an LED packaging with single walled carbon nanotubes as a heat sink. The 5W LED packaging is simulated with different types of LED chips materials which comprise gallium nitride, indium nitride, zinc oxide, zinc selenide and titanium dioxide. Using LED chips materials as the heat source, the heat flow is conducted through the bottom layer to the heat sink and dissipates by convection or radiation heat transfer to the surrounding. The addition of thin film on top of the phosphorus layer functions to enhance the recombination rate and guided the flow of heat to the bottom. The 5W titanium dioxide light emitted diode packaging (LED packaging C) has been successfully demonstrated to have overall temperature reduced to around ~10°C by using single walled carbon nanotube heat sink as compared to copper heat sink and aluminium heat sink. Meanwhile, carbon material as thermal interface material and substrate also plays a major role as a thermal cooling solution in LED packaging. For 5W titanium dioxide light emitted diode packaging, under self-heating conditions, the maximum average temperature generated is 81.05 °C. Despite that, under convection conditions, the maximum average temperature generated is 41.53°C.

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Characterization of all-optical Tofolli and Peres gates employing optimized SOA-NOLM

2020-01-08 , Nur Hafizah Ghazali , Mohamad Halim Abd. Wahid , Nor Azura Malini Ahmad Hambali , Nurjuliana Juhari , Zahari S.M. , Shahimin M.M.

In this work, all-optical reversible gates namely Tofolli and Peres are studied and characterized. The gates utilize semiconductor optical amplifier (SOA) in nonlinear loop optical mirror (NOLM). The reversible gates are performed at data rate 10 Gb/s with narrow Gaussian pulses as input signals. Delay of 130 ps and injection current of 170 mA have displayed the optimum outputs in the SOA-NOLM. Extinction ratio is greatly reduced, thus less noise interferes the logic operation in this simple technique. It is observed that Peres gate has shown a higher output power compare to Toffoli gate. This could be due to multiple amplification that are experienced by the signals. Other than the gain, injection current and delay are shown to give major effect in producing the correct bits at the outputs. The SOA-NOLM also can be cascaded for other arithmetic signal processing operation at high frequency. It is also recorded that the design consumes low power especially in small signal gain process. Thus, the design indicates its versatility to be executed in photonic integrated circuits for ultrafast signal control through fiber networks.

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UWB triplet and quadruplet pulses generation employs nonlinear effect in semiconductor optical amplifier nonlinear loop mirror

2020-01-08 , Zahari, Suhaila Mohd , Mohamad Halim Abd. Wahid , Nor Azura Malini Ahmad Hambali , Nurjuliana Juhari , Ghazali N.F. , Shahimin M.M.

Ultrawideband (UWB) triplet and quadruplet pulses generation exploits nonlinear effect in semiconductor optical amplifier (SOA) in nonlinear loop mirror (NOLM) is investigated in this work. Two signals are transmitted through the SOA-NOLM simultaneously to create cross-phase modulation (XPM) effect. Firstly, the XPM causes the production of doublet which later combines for creation of triplet and quadruplet. This technique engages a proper tuning of optical delay and a selection of suitable power in all loops. Besides, injection current of the SOAs also governs the formation of these pulses. Although, frequency of the signals can be varied accordingly, the pulses are limited to certain adjustment that shifted its position in time domain. Furthermore, the set up can also be assessed for monocycle and doublet pulses by extracting the output at several positions. It can be concluded that the design may work as multiple pulses generation. All pulses are examined and compared with their electrical spectrum counterpart for validity of this approach.

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Two dimensional (2D) OCDMA encoder-decoder for various industrial application

2021-12 , Syed Alwee Aljunid Syed Junid , Mohd Arif Anuar Mohd Salleh , A A M Ismail , ND Keraf , R Matem , Mohd Rashidi Che Beson , Norshamsuri Ali @ Hasim , Mohd Shafiq Amirul , Rosdisham Endut , Nor Azura Malini Ahmad Hambali

Future telecommunication systems and networks are expected to provide a variety of integrated broadband services to the customers. There has been a tremendous interest in applying Code Division Multiple Access (CDMA) techniques to fiber optic communication systems. This technique is one of the multiple access schemes that is becoming popular because of the flexibility in the allocation of channels, ability to operate asynchronously, enhanced privacy and increased capacity in bursty networks. This project is focusing on designing 2D OCDMA system with the hardware implementation of design using FPGA. The coding techniques in OCDMA are time versus wavelength and amplitude versus phase. 2D OCDMA coding incorporates both wavelength selection and time distribution. The data bit would be encoded as consecutive chips with various wavelengths. The code architecture seeks to produce codes with high autocorrelation and low cross-correlation properties. Code length is an essential aspect of code and device architecture for coding characteristics. The hardware implementation of the system is designed by using FPGA De1-SoC. The FPGA have the abilities to enhance the transmission of data to the receiver in a short period of time. The performance of 2D OCDMA system is expected to surpass 1D OCDMA system in terms of BER and the number of simultaneous users that can be supported. The system encoder and decoder were designed using optical switch, splitter, combiner and modulator. The performance of 2D OCDMA system in terms of time spreading and wavelength spreading is also compared which shown a huge difference in the results. The best performance of the system is when the number of wavelength (M) is fixed to 18 and the number of times spreading (N) is 31 which can support 350 more simultaneous users.

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Generation Orbital Angular Momentum Modes Using Metasurfaces

2023-10-06 , NHuda S. , Norshamsuri Ali @ Hasim , Amphawan A. , Nor Roshidah Yusof , Rosdisham Endut , Nor Azura Malini Ahmad Hambali , Mohd Najib Mohd Yasin , Syed Alwee Aljunid Syed Junid

The purpose of this study is to investigate how numerous orbital angular momentum (OAM) modes may be produced by mixing acoustic plane beams with different metasurfaces. This study proposes a novel metasurface that may be simulated in order to generate OAM beams. Multi-beam and multi-mode terahertz wave incidence are produced utilizing vortex modes in the beams. The study of suitable OAM superpositions of waveguide eigenmodes is done using COMSOL Multiphysic, followed by a description of the software's usage and examples of challenges involved. With the existence of these studies, we can also prove that the mode can be produced completely with the results that have been studied. Based on the results obtained, an objective was achieved, which is to design the feature of the vortex beam modes. These results include the construction of a multi-functional vortex beam based on a theoretical model of phase gradient distribution. Also, by using metasurface mimics to specify a periodic structure specified by the user from the built-in unit cell, and the beam was attenuated and split into two paths inside the thin layer. Finally, the simulation process between 2D and 3D is very significant because the mesh and geometry in a design are very different, but generating a beam using COMSOL already has a specific module, namely the wave optic module, which can be used to predict the beam modes.

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Geometrical optimization of lithium niobate on insulator rib waveguide for quantum communication application

2020 , Nor Roshidah Yusof , Norshamsuri Ali @ Hasim , P. Kolenderski , Nor Azura Malini Ahmad Hambali , Syed Alwee Aljunid Syed Junid

Recently, thin film Lithium niobate has been recognized as an alternative material to silicon based technology due to its capability to support a broader range for quantum communication system. With the aim to operate within single photon application, we demonstrate the mode distribution, propagation constant and effective refractive indices of the Lithium Niobate on Insulator rib waveguide which operates at both fundamental wavelength, 1550 nm and second harmonic wavelength, 775 nm, respectively by using Finite Element Method. The etched depth and width of the core was varied from 340 to 400 nm and 700 to 1400 nm, respectively with the thickness of slab is fixed at 100 nm. From the result, it shows the effective refractive index increases gradually with the increment of etched depth and width of core, respectively. At second harmonic wavelength, the effective refractive indices and propagation constant shows a significant increment compare to observation at 1550 nm with an ability to produce both fundamental mode and first order mode across the structure.

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Modeling on impact of metal object obstruction in urban environment for internet of things application in vehicular communication

2020-01-08 , Turner J.S.C. , Azizi Harun , Mohd Najib Mohd Yasin , Norshamsuri Ali @ Hasim , Shahriman Abu Bakar , Fadzilla M.A. , Sohiful Anuar Zainol Murad , Nor Azura Malini Ahmad Hambali , Razlan Z.M. , Mohd Sani Mohamad Hashim , Wan Khairunizam Wan Ahmad , Phoon C.Y.

Objects such as vehicles are considered one of challenging obstruction on the road and very little attention has been made to address its significance on the wireless signal. As such, this paper validates the impact of vehicle obstruction on signal propagation using received signal strength indicator (RSSI) based on the wireless channel measurements of realistic environmental obstruction at 2.4 GHz frequency band. Low mobility IEEE 802.15.4 XBee S2C compliant device which is designed to collect received signal power was used and these devices were deployed at area congested with cars. The channel measurements were conducted on LOS car parking area with two scenarios; single-sided and double-sided vehicle obstruction which mimics the obstruction of metal objects. The effect of existing vehicle on the signal propagation is demonstrated based on RSSI and RMSE. The attenuation profile of vehicular obstruction on wireless signal is modeled and compared with large-scale propagation models. Results show that metal object significantly reduce transmission range and signal power. The findings may incite for future implementation of cooperative deployment program and internet of things (IoT) applications in vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication.

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Smart embedded-analytics sensors with cloud-based measurement system for HVAC

2020-01-08 , Aseri N.S.M. , Norshamsuri Ali @ Hasim , Mohd Najib Mohd Yasin , Mohd Rashidi Che Beson , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Nor Azura Malini Ahmad Hambali , Shapiai M.I.

HVAC system is a necessary component of environment to maintain the temperature and humidity to be kept at certain levels by using air taken from outside to ensure the indoor comfort. The purpose of the study is to reduce the electricity energy usage and cost from air conditioning by using smart embedded-analytics sensors to provide the automatic thermal control in an area. In this study, we used sensors such as temperature and humidity sensors to detect and read the currently temperature and humidity of an area monitored by a microcontroller. The cloud-based system and the sensors are connected via wifi in the presence of MQTT protocol. The protocol enables publish and subscribe method which provide the communication between sensors, cloud-based system and HVAC system. This communication can serve thermal control automatically thus resulting the optimize usage of energy from air conditioning according to the external environment temperature and humidity. The control of the temperature and humidity from air conditioning can be designed through the programming embedded in the microcontroller. The monitoring result can be displayed from the control panel to ensure how the system works.

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