Now showing 1 - 5 of 5
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Enhancement receiver sensitivity under heavy attenuation effect for FSO system via double transmission technique

2024-02-08 , Thai S.A.K. , Rahman A.K. , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Norshamsuri Ali @ Hasim , Mohd Rashidi Che Beson

This paper focus on improvement of receiver sensitivity for free space optical communication. FSO communication is frequently drop performance when facing bad weather. In this research proposed new development of transmitter and receiver design in order to reduce the impact of atmospheric attenuation and increase receiver sensitivity. The analysis performance will compare with conventional amplitude shift keying (ASK) approach. Simulation result will be used to measure the performance and comparison between conventional and new proposed modulation double transmission balance receiver (DTBR) will also presented. The measurement of result will involve the effect of geometrical loss, data bit rate and distance propagation. From the result, the DTBR is increase the receiver sensitivity in term of bit error rate (BER) performance.

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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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Prediction rain attenuation effect on free space optical communication Kuching/Samarahan Region

2024-02-08 , Rahman A.K. , Thai S.A.K. , Rosdisham Endut , Syed Alwee Aljunid Syed Junid , Norshamsuri Ali @ Hasim , Mohd Rashidi Che Beson

Rain attenuation is significantly affecting the FSO performance of a free-space optical communication system. Kuching/Samarahan region is situated in Malaysia state which is under tropical climate zone. The rain distribution is recorded high due to having rain season year-round. It worst when turn to monsoon season where the precipitation rate is expected high and dense. It is crucial to design the effect FSO system to ensure good quality transmission beam signal. This paper is focus on Kuching/Samarahan zone as the preliminary result to investigate the rain pattern and effect over FSO propagation. The investigation it focuses on that region is due to development that area to implement fully digital economy which need supported by high speed and capacity data that can be produced by optical technology. Therefore, FSO technology can perform this task. The rain data is collected from Malaysia Meteorology Department (Met Malaysia) which for three years 2017, 1018 and 2019. The performance will measure the effect of scattering coefficient, rain attenuation and geometrical loss. It is expected heavy rain will contribute the great impact over FSO link.

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Waveguide for vortex mode generation in HVAC cloud management communication

2020-01-08 , Norshamsuri Ali @ Hasim , Amphawan A. , Hafizalshah M.H. , Syed Alwee Aljunid Syed Junid , Rosdisham Endut , Mohd Rashidi Che Beson , Mohd Najib Mohd Yasin , Shapiai M.I.

Optical modes allow for the transmission of data by propagating light in a singular coherent form along the channel. By constructing a special waveguide structure, a unique mode may be formed in a plane perpendicular to the transmission axis. This paper elucidates on the design of a waveguide to generate unique vortex modes and analyses the properties of the generated modes.

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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.