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All Journal TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics Indonesian Journal of Electrical Engineering and Computer Science
S. H. Dahlan
Universiti Tun Hussein Onn Malaysia
Computer Science & IT Electrical & Electronics Engineering

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An Upgraded Transverse Electromagnetic Parallel Plates for Dielectric Measurement S. K. Yee; R. Padu; C. K. Sia; X. T. I. Ngu; S. H. Dahlan; M. A. Azlan
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 15, No 3: September 2017
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v15i3.7213

Abstract

A new version of transverse electromagnetic parallel plates with irregular plates’ width and plate separation has been developed for dielectric measurement. The separations between the plates are supported by four rectangular Teflon block and 1 mm of groove is proposed at the center of the upper plate to maintain the measurement repeatability. The groove enables the samples which are slightly higher than 2 cm to be fitted well between the plates without introducing extra force to the plates. Theperformance of both parallel plates has been compared in the frequency range from 100 MHz to 1.1 GHz. It is found that the upgraded parallel plate offers better return loss and insertion loss above 500 MHz compared to the previous parallel plate. It is reported from this work that the return loss of the parallel plate must be lower than -15 dB in order to achieve accurate dielectric constant. However, the insertion loss of the parallel plates does not influence the real permeability significantly. The upgraded TEM parallel plateproduces a consistent reading with a standard deviation of less than 0.05 above frequency 200 MHz. The dielectric measurement of Polypropylene (PP) has proven the capability of this upgraded TEM parallelplate.
A compact dual-band semi-flexible antenna at 2.45 GHz and 5.8 GHz for wearable applications S. M. Shah; A. A. Rosman; M. A. Z. A. Rashid; Z. Z. Abidin; F. C. Seman; H. A. Majid; S. H. Dahlan; S. A. Hamzah; N. Katiran; A. Ponniran; F. Hassan; F. Zubir
Bulletin of Electrical Engineering and Informatics Vol 10, No 3: June 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v10i3.2262

Abstract

In this work, a compact dual-band semi-flexible antenna operating at         2.45 GHz and 5.8 GHz for the industrial, scientific and medical (ISM) band is presented. The antenna is fabricated on a semi-flexible substrate material, Rogers Duroid RO3003™ with a low-profile feature with dimensions of 30×38 mm2 which makes it a good solution for wearable applications. Bending investigation is also performed over a vacuum cylinder and the diameters are varied at 50 mm, 80 mm and 100 mm, that represents the average human arm’s diameter. The bending investigation shows that reflection coefficients for all diameters are almost similar which imply that the antenna will operate at the dual-band resonant frequencies, even in bending condition. The simulated specific absorption rate (SAR) in CST MWS® software shows that the antenna obeys the FCC and ICNIRP guidelines for 1 mW of input power. The SAR limits at 2.45 GHz for 1 g of human tissue is simulated at 0.271 W/kg (FCC standard: 1.6 W/kg) while for 10 g is at 0.0551 W/kg (ICNIRP standard: 2 W/kg. On the other hand, the SAR limits at 5.8 GHz are computed at 0.202 W/kg for 1 g and 0.0532 W/kg for 10 g.
Dual band low loss metamaterial structure at millimetre wave band B. A. F. Esmail; H. A. Majid; M. F. Ismail; S. H. Dahlan; Z. Z. Abidin; M. K. A. Rahim
Indonesian Journal of Electrical Engineering and Computer Science Vol 15, No 2: August 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v15.i2.pp823-830

Abstract

In this paper, the Dual band modified split square resonator (MSSR) metamaterial (MM) structure was designed and numerically investigated at millimetre wave (mm-Wave) frequency range. The proposed structure operated at two resonance frequencies 28 GHz and 32.54 GHz. The dual-band behaviour of the proposed structure because of the self and mutual coupling between two metallic squares of the structure. Furthermore, The MSRR structure performed very well at both resonance frequencies by providing high transmission coefficient, S21, with a loss of -0.3 dB (0.97 linear scale) at lower resonance frequency 28 GHz and -0.18 dB (0.98 linear scale) at upper resonance frequency 32.54 GHz. In this regard, the numerical simulation was conducted to optimize the MSSR structure in such a way that the ratio of effective inductance-to-capacitance (L/C) was raised. As a result, the inherent MM losses were reduced. The robust retrieval algorithm was utilized to reconstruct the refractive index, effective permittivity, and effective permeability and to verify the left-hand property of the proposed structure. The simulation results showed that the MSSR unit cell introduces two regions of the negative refractive index below the lower resonance frequency, 28 GHz and above the upper resonance frequency, 32.54 GHz.
Co-Authors A. A. Rosman A. Ponniran B. A. F. Esmail C. K. Sia F. C. Seman F. Hassan F. Zubir H. A. Majid M. A. Azlan M. A. Z. A. Rashid M. F. Ismail M. K. A. Rahim N. Katiran R. Padu S. A. Hamzah S. K. Yee S. M. Shah X. T. I. Ngu Z. Z. Abidin