Articles
<![CDATA[Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigurability using EBGs ]]>
<![CDATA[Raimi Dewan]]>;
<![CDATA[M. K. A. Rahim]]>;
<![CDATA[M. R. Hamid]]>;
<![CDATA[M. F. M. Yusoff]]>;
<![CDATA[H. A. Majid]]>;
<![CDATA[B. A. F. Esmail]]>
<![CDATA[ International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 4: August 2018 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijece.v8i4.pp2557-2563
<![CDATA[A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism. By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application.]]>
<![CDATA[The Improvement of first Iteration Log Periodic Fractal Koch Antenna with Slot Implementation ]]>
<![CDATA[N. S. M. Yaziz]]>;
<![CDATA[M. K. A. Rahim]]>;
<![CDATA[F. Zubir]]>;
<![CDATA[N. S. Nadzir]]>;
<![CDATA[R. Dewan]]>;
<![CDATA[H. A. Majid]]>
<![CDATA[ International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 4: August 2018 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijece.v8i4.pp2564-2570
<![CDATA[In this paper, a slotted is introduced at each of the radiating elements on the 1st iteration log periodic fractal Koch antenna (LPFKA). The antenna is designed to testify the appropriate performance at UHF Digital television which operates from 4.0 GHz to 1.0 GHz. The dimension of the conventional 0th iteration LPKFA is successfully reduced by 17% with the implementation of slotted. The results show a good agreement with a stable radiation pattern across the operating bandwidth, stable gain more than 5 dBi and reflection coefficient of below -10 dB over the desired frequency range.]]>
<![CDATA[Switchable Wideband Metamaterial Absorber and AMC reflector for X-band Applications and Operations ]]>
<![CDATA[M. M. Gajibo]]>;
<![CDATA[M. K. A. Rahim]]>;
<![CDATA[N. A. Murad]]>;
<![CDATA[O. Ayop]]>;
<![CDATA[H. A. Majid]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 16, No 4: August 2018 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v16i4.9065
<![CDATA[A single layered metamaterial structure with capabilities of switching from a wideband metamaterial absorber to an AMC reflector and vice versa is presented in this paper. A flame retardant 4 substrate with physical thickness of 1.60mm was used. The absorption rate, reflection rate, reflection phase and surface current distribution were studied and discussed. The operational incidental wave angles were varied from 0o to 65o. A peak reflection of about 90% was achieved at 11.20 GHz with a usable bandwidth (-90 to +90) of 3.01 GHz by the AMC reflector. The metamaterial absorber demonstrated a wideband performance (from 8.10 GHz to 14.30 GHz). It achieved 100% absorption at 11.20 GHz and not less than 65]]>
<![CDATA[Fractal Yagi-Uda antenna for WLAN applications ]]>
<![CDATA[Amerrul Zabri]]>;
<![CDATA[M. K. A. Rahim]]>;
<![CDATA[F. Zubir]]>;
<![CDATA[N. M. Nadzir]]>;
<![CDATA[H. A. Majid]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 5: October 2019 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v17i5.12797
<![CDATA[This paper describes the development of a Fractal printed Yagi-Uda antenna for Wireless Local Area Network (WLAN) applications operating at 2.4 GHz frequency. In miniaturizing the dimensions of an antenna, fractal method is applied where the 1st iteration and 2nd iteration is implemented. The Computer Simulation Technology (CST) software is used as the platform to design and simulate the antenna. The substrate material used is the FR-4 board which has a dielectric constant of 5.4, the thickness of 1.6mm and tangent loss of 0.019. The antenna performance interm of the reflection coefficient, radiation pattern and gain are compared and analyzed. For the 1st iteration, 22.81% of reduction size has been achieved and 30.81% reduction of the antenna size for 2nd iteration has been achieved.]]>
<![CDATA[Mutual Coupling Reduction in Antenna Using EBG on Double Substrate ]]>
<![CDATA[Raimi Dewan]]>;
<![CDATA[M. K.A. Rahim]]>;
<![CDATA[M. R. Hamid]]>;
<![CDATA[M. E. Jalil]]>;
<![CDATA[H. A. Majid]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 15, No 2: June 2017 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v15i2.6123
<![CDATA[In this paper, a mutual coupling studies is conducted between two-element array antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on dual substrate are constructed with one of them is incorporated with three EBG unit cell on the bottom substrate. The radiating patch is on the top substrate, while the EBG unit cells is on the bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements are closely separated by a distance of 22 mm with a significant reduced mutual coupling of -26.61 dB. This correspond to a distance reduction of 34.68%. The proposed structure implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG with the antenna is also presented.]]>
<![CDATA[Meander bowtie Antenna for Wearable Application ]]>
<![CDATA[N. Othman]]>;
<![CDATA[N. A. Samsuri]]>;
<![CDATA[M. K. A. Rahim]]>;
<![CDATA[K. Kamardin]]>;
<![CDATA[H. A. Majid]]>
<![CDATA[ TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 16, No 4: August 2018 ]]>
Publisher : <![CDATA[Universitas Ahmad Dahlan ]]>
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DOI: 10.12928/telkomnika.v16i4.9061
<![CDATA[This paper proposes a flexible compact bowtie antenna for medical application that operates at 2.45 GHz. The proposed antennas are miniaturized using meander technique. Both substrates and conducting material of the antenna are made of flexible material semi-transparent film as the substrate and shieldit fabric as the conducting material which suitable for wearable and on body application. The results show that the total length of the antenna is significantly reduced by up to 38%. However, the gain of the antenna is slightly decreased when the size of the antenna become smaller. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application.]]>
<![CDATA[A compact dual-band semi-flexible antenna at 2.45 GHz and 5.8 GHz for wearable applications ]]>
<![CDATA[S. M. Shah]]>;
<![CDATA[A. A. Rosman]]>;
<![CDATA[M. A. Z. A. Rashid]]>;
<![CDATA[Z. Z. Abidin]]>;
<![CDATA[F. C. Seman]]>;
<![CDATA[H. A. Majid]]>;
<![CDATA[S. H. Dahlan]]>;
<![CDATA[S. A. Hamzah]]>;
<![CDATA[N. Katiran]]>;
<![CDATA[A. Ponniran]]>;
<![CDATA[F. Hassan]]>;
<![CDATA[F. Zubir]]>
<![CDATA[ Bulletin of Electrical Engineering and Informatics Vol 10, No 3: June 2021 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/eei.v10i3.2262
<![CDATA[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.]]>
<![CDATA[A 2.45 GHz microstrip antenna with harmonics suppression capability by using defected ground structure ]]>
<![CDATA[Shaharil Mohd Shah]]>;
<![CDATA[M. Mohamad]]>;
<![CDATA[S. A. Hamzah]]>;
<![CDATA[Z. Z. Abidin]]>;
<![CDATA[F. C. Seman]]>;
<![CDATA[N. Katiran]]>;
<![CDATA[H. A. Majid]]>;
<![CDATA[A. Ashyap]]>;
<![CDATA[S. Mohamad]]>
<![CDATA[ Bulletin of Electrical Engineering and Informatics Vol 9, No 1: February 2020 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/eei.v9i1.1847
<![CDATA[In this work, a microstrip patch antenna with an inset feed and defected ground structure (DGS) is designed at the resonant frequency of 2.45 GHz. The antenna is designed on a FR-4 substrate with a dielectric constant, εr of 4.5, loss tangent, tan δ of 0.019 and thickness, h of 1.6 mm. The technique of DGS is used to avoid the use of additional circuits in the antenna to suppress the harmonics. By introducing a single and additional slots DGS at both ends on the antenna ground plane, the proposed microstrip patch antenna is able to suppress the higher order harmonics. The reflection coefficient, S11 is -38.75 dB at 2.45 GHz. The proposed antenna have suppressed the higher order harmonics effectively from -38.04 dB to -2.61 dB at 4.54 GHz and from -13.08 dB to -1.38 dB at 5.76 GHz. The prototype of the antenna is fabricated for the verification of the design. The simulated and measured results are found to be in a good agreement.]]>
<![CDATA[Negative refraction metamaterial with low loss property at millimeter wave spectrum ]]>
<![CDATA[B. A. F. Esmail]]>;
<![CDATA[H. A. Majid]]>;
<![CDATA[F. A. Saparudin]]>;
<![CDATA[M. Jusoh]]>;
<![CDATA[A. Y. Ashyap]]>;
<![CDATA[Najib Al-Fadhali]]>;
<![CDATA[M. K. A. Rahim]]>
<![CDATA[ Bulletin of Electrical Engineering and Informatics Vol 9, No 3: June 2020 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/eei.v9i3.1853
<![CDATA[The design of the millimeter-wave (MMW) metamaterials (MMs) unit cell operates at 28 GHz is presented and numerically investigated. The proposed structure composed of a modified split ring resonator (MSRR) printed on both sides of the substrate layer. Popular MM structures such as S-shape, G-shape, and Ω-shape are adjusted to operate at the 28 GHz for comparison purpose. MSRR achieves a wide bandwidth of 1.1 GHz in comparison with its counterparts at the resonance frequency. Moreover, the proposed structure presents very low losses by providing the highest transmission coefficient, S21, at the corresponding frequency region. The radiation loss is substantially suppressed and the negativity of the constitutive parameters of the proposed MM structure is maintained. By applying the principle of the electromagnetically induced transparency (EIT) phenomenon, the MSRR unit cell induces opposite currents on both sides of the substrate which leads to canceling out the scattering fields and suppresses the radiation loss. The constitutive parameters of the MM structures are retrieved using well known retrieval algorithm. The proposed structure can be used to enhance the performance of fifth generation (5G) antenna such as the gain and bandwidth.]]>
<![CDATA[X-band Operations Metamaterial Absorber with Extended Circular Ring Topology for Size Reduction ]]>
<![CDATA[M. M. Gajibo]]>;
<![CDATA[M. K. A. Rahim]]>;
<![CDATA[N. A. Murad]]>;
<![CDATA[O. Ayop]]>;
<![CDATA[B. D. Bala]]>;
<![CDATA[H. A. Majid]]>
<![CDATA[ Indonesian Journal of Electrical Engineering and Computer Science Vol 6, No 1: April 2017 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijeecs.v6.i1.pp180-184
<![CDATA[A metamaterial electromagnetic wave absorber consisting of a big circular ring patch with four smaller suppression circular rings is presented in this report. The metamaterial electromagnetic wave absorber introduces the concept of size reduction by suppressing the resonance frequency. An FR4 substrate was used and the incidental wave angles were varied from 00 to 600. Simulations results shows peak absorption of 100% was achieved at 10.7 GHz by the absorber for both TE and TM polarization incident waves. Minimum absorption for both TE and TM mode of 90.6% was achieved under TE mode. The metamaterial absorber was being tested with and Ultra-wide band antenna and the results were reported.]]>
