S. A. Hamzah
Universiti Tun Hussein Onn Malaysia

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Frequency Reconfiguration Mechanism of a PIN Diode on a Reconfigurable Antenna for LTE and WLAN Applications S. M. Shah; M. F. M. Daud; Z. Z. Abidin; F. C. Seman; S. A. Hamzah; N. Katiran; F. Zubir
International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 3: June 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (780.892 KB) | DOI: 10.11591/ijece.v8i3.pp1893-1902

Abstract

Microstrip patch antennas are increasingly gaining popularity for usage in portable wireless system applications due to their light weight, low profile structure, low cost of production and robust nature. The patch is generally made of a conducting material such as copper or gold and can take any possible shapes, but rectangular shapes are generally used to simplify analysis and performance prediction. Microstrip patch antenna radiates due to the fringing fields between the patch edge and ground plane. In this work, a frequency reconfigurable antenna with a BAR63-02V Positive-Intrinsic-Negative (PIN) diode is designed, simulated and fabricated. The antenna operates at 2.686GHz for Long-Term Evolution (LTE2500) and 5.164GHz for Wireless Local Area Network (WLAN) applications. In the OFF state, the antenna operates at 5.302GHz, which is also suitable for WLAN application. The proposed antenna is fabricated on a FR-4 substrate with a relative dielectric constant, εr of 4.5, thickness, h of 1.6mm and loss tangent, tan δ of 0.019. The fabrication process is carried out at the Advanced Printed Circuit Board (PCB) Design Laboratory in UTHM.
Microstrip to Parallel-Strip Nonlinear Transition Balun with Stubs and DGS for UWB Dipole Antenna S. A. Hamzah; S. Mohd Shah; H. Majid; K. N. Ramli; M. S. Zainal; L. Audah; S. Z. Sapuan; A. Ubin; M. Esa; N. N. Nik Abd Malik
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.v15i3.7216

Abstract

Three tapered baluns with nonlinear transition are developed for harmonic suppression in dipole antenna. The first balun consists of an exponential profile with the size of a quarter–wavelength for both the height and width with a wideband characteristic. However, for some applications such as narrowband harmonic suppression antennas and wideband-to-narrowband reconfigurable antennas, the suppression of higher operating band is desired. By employing stubs-filter and a defected ground structure (DGS), two narrowband tapered baluns are produced. They are named as an exponential balun-stub and an exponential balun-DGS, respectively, that operate from 1 to 2 GHz. A simulated and measured results that based on the reflection coefficient is found to be better than -10 dB from 1 to 2 GHz. The employment of the stubs and DGS have enabled these baluns to have the capability to reject the unwanted higher frequency band from 2.0 to 10 GHz. Finally, the proposed baluns are employed as a feeding circuit for an ultra wideband (UWB) circular dipole antenna that produces a reasonable outcome.
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.
A 2.45 GHz microstrip antenna with harmonics suppression capability by using defected ground structure Shaharil Mohd Shah; M. Mohamad; S. A. Hamzah; Z. Z. Abidin; F. C. Seman; N. Katiran; H. A. Majid; A. Ashyap; S. Mohamad
Bulletin of Electrical Engineering and Informatics Vol 9, No 1: February 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (667.203 KB) | DOI: 10.11591/eei.v9i1.1847

Abstract

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.
Frequency tuning varactor-loaded reconfigurable antenna for m-WiMAX and WLAN applications S. M. Shah; K. Hamdan; Z. Z. Abidin; F. C. Seman; S. A. Hamzah; N. Katiran; F. Zubir
Indonesian Journal of Electrical Engineering and Computer Science Vol 13, No 2: February 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v13.i2.pp779-786

Abstract

A design approach for a microstrip patch antenna to achieve the reconfigurable dual-band operation with a tunable device is presented in this work. The approach uses a BB833 varactor diode in the middle of a slotted patch antenna which which is able to produce dual-band resonant frequencies. The reconfigurable antenna is designed and simulated in CST Microwave Studio® software and is later, fabricated on a FR-4 substrate with a dielectric constant,  of 4.5, loss tangent, tan δ of 0.019 and thickness, h of 1.6 mm. By changing the DC voltages of the varactor diode, different capacitance values of the varactor diode are obtained which dictate the specific resonant frequencies. From the simulation results, the capacitance value of 0.5 pF with a bias voltage of 2.0 V is chosen as it produces the required dual-band resonant frequencies at 3.38 GHz and 5.37 GHz for desired applications in the m-WiMAX and WLAN bands.
A 2.45 GHz Semi-Flexible wearable antenna for industrial, scientific and medical band applications S. M. Shah; N. F. A. Kadir; Z. Z. Abidin; F. C. Seman; S. A. Hamzah; N. Katiran
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.pp814-822

Abstract

In this work, a compact size, wearable microstrip patch antenna is designed, simulated and fabricated for the Industrial, Scientific and Medical (ISM) band applications with the operating frequency at 2.45 GHz. A semi-flexible substrate material which is Rogers Duroid RO3003™ with a relative dielectric constant, ε_r of 3, loss tangent, tan δ of 0.010 and thickness, h of 1.52 mm has been proposed to ensure it can be worn on clothes. The antenna has a low-profile feature with 24 × 28 mm2 in dimension. Investigation of the antenna under bending condition on the approximate human arm size is also performed and analysed to ensure that the wearable antenna is applicable for on-body. The bending investigation shows that the initial resonant frequency of 2.45 GHz is shifted to 2.3 GHz. However, the reflection coefficient at 2.45 GHz is still greater than the -10-dB which implies that the antenna is still functional at that particular frequency. The Specific Absorption Rate (SAR) of the antenna has also been simulated to examine whether the antenna obeys the SAR limits under the FCC and CNIRP guidelines. The SAR values obtained show that the antenna obeys the standard for 1 mW input power. The SAR value for 1g of human tissue is computed at 0.03999 W/kg (FCC standard: 1.6 W/kg) while for 10g is at 0.01936W/kg (CNIRP standard: 2 W/kg).