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All Journal TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics
Ahmad Syahiman Mohd Shah
Universiti Malaysia Pahang
Computer Science & IT Electrical & Electronics Engineering

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Flat lens design using phase correction technique for horn antenna applications Nur Hazimah Syazana Abdul Razak; Nur Shahira Mat Hussain; Nurul Hazlina Noordin; Syamimi Mardiah Shaharum; Ahmad Syahiman Mohd Shah; Mohamad Shaiful Abdul Karim
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 19, No 1: February 2021
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v19i1.16212

Abstract

A design of a flat dielectric lens is presented in this study to enhance directivity of a pyramidal horn antenna. The horn antenna is proposed to cover frequency of medical imaging system, which is between 5 and 6 GHz, and dielectric lens is designed based on phase correction techniques. The spherical waves produced by conventional horn antenna is being transform to planar waves by resorting flat lens in order to achieve a highly directive radiation in the farfield region. This is done by drilling numerous holes with different diameters through the dielectric material to produce different phase delay. The radiation characteristics of the lens are simulated using CST Microwave Studio and then compared with measured results. The results showed a good performance for radiation pattern when the lens is attached. This proposed design shows a significant increment of sidelobe level and 3-dB beamwidth between 5 and 6 GHz.
Widespread compact fluorescent lamp evaluations in 50 Hz electrical network Ruhaizad Ishak; Ahmad Syahiman Mohd Shah; Mohd Ikhwan Muhammad Ridzuan; Noraslinda Muhamad Bunnori
Bulletin of Electrical Engineering and Informatics Vol 12, No 3: June 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v12i3.4904

Abstract

Rapid development in electrical technology has imposed strong challenges to modern power system. Power quality has become a great concern due to proliferation of power electronic technology in modern electrical loads. Specifically for lighting load such as compact fluorescent lamps (CFLs), one of the concerning issues is harmonics. CFL is a cost-competitive and energy efficient compared to incandescent lamp. Inevitably, CFL produces harmonics current due to nonlinearity behaviour of the electronic ballast circuit. This paper presents a study on the widespread installation of CFL lamps in electrical power network. Initially, the harmonic current characteristics of local-branded CFL was identified from laboratory measurement. Then, a simulated CFL model was developed in MATLAB/Simulink to replicate the identified characteristics. The same step was repeated for other two different brands where eventually all models were embedded into a distribution network. The results show that at low voltage level, with installation more than 50 units for each type of CFL, the harmonic voltage distortion exceeded the 8% total harmonic distortion (THD) limit as stipulated in EN50160 standard. However, at higher voltage, the amount of THD decreased to average 0.94% and further down to average 0.28% at small transmission voltage level.
Co-Authors Mohamad Shaiful Abdul Karim Mohd Ikhwan Muhammad Ridzuan Noraslinda Muhamad Bunnori Nur Hazimah Syazana Abdul Razak Nur Shahira Mat Hussain Nurul Hazlina Noordin Ruhaizad Ishak Syamimi Mardiah Shaharum