Huda A. Majid
Universiti Tun Hussein Onn Malaysia (UTHM)

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Parametric Analysis of Wearable Vialess EBG Structures and Its Application for Low Profile Antennas Adel Y.I. Ashyap; Zuhairiah Zainal Abidin; Samsul Haimi Dahlan; Huda A. Majid; Zuraidah Muhammad; Muhammad Ramlee Kamarudin
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 15, No 2: June 2017
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v15i2.6108

Abstract

This paper is under in-depth investigation due to suspicion of possible plagiarism on a high similarity indexElectromagnetic Bandgap (EBG) structures are one class of metamaterial with attractive properties that unavailable in nature and widely used for improving the electromagnetic performance. Its In-phase reflection frequency band is indicated as operation frequency band, whose characteristic is closely related to the parameters of EBG structure, such as patch width (w), gap width (g), substrate height (h) and substrate permittivity (ε). The presence of via within EBG structure is associated with design and fabrication complexities, which led the researchers to study uniplanar EBG. These structures require no via and can easily be fabricated and integrated with RF and microwaves application.  Therefore, an investigation study on the effect of the parameters of the vialess EBG surface and some design guidelines have been obtained. An example of an antenna integrated with EBG is also studied. The result indicates that the EBG ground plane significantly improves the work efficiency of the antenna in a particular frequency band.
SPDT discrete switch design using switchable SIW resonators for millimeter wave MIMO transceiver Amirul Aizat Zolkefli; Badrul Hisham Ahmad; Noor Azwan Shairi; Adib Othman; Zahriladha Zakaria; Imran Mohd Ibrahim; Huda A. Majid
Indonesian Journal of Electrical Engineering and Computer Science Vol 24, No 3: December 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v24.i3.pp1542-1549

Abstract

A single pole double throw (SPDT) discrete switch design using switchable substrate integrated waveguide (SIW) resonators is proposed in this paper. It was designed for the millimeter wave multiple input multiple output (MIMO) transceiver. An example application is for 5G communication in 26 GHz band. High isolation between transmitter and receiver (in the transceiver) is needed in SPDT switch design to minimize any high radio frequency (RF) power leakage in the receiver. Therefore, the use of switchable SIW resonators can achieve higher isolation if compared to the conventional series SPDT switch, where the isolation of the proposed SPDT is depend on the bandstop response of the SIW resonators. The switchable SIW resonators can be switched between allpass and bandstop responses to allow the operation between transmit and receive modes. As a result, the simulation and measurement showed that the proposed SPDT switch produced an isolation higher than 25 dB from 24.25 to 27.5 GHz compared to the conventional design.
A wearable antenna based on fabric materials with circular polarization for Body-centric wireless communications Adel Y. I. Ashyap; Z. Z. Abidin; Samsul Haimi Dahlan; Shaharil Mohd Shah; Huda A. Majid; Yee See Khee; Norun Abdul Malek
Indonesian Journal of Electrical Engineering and Computer Science Vol 18, No 1: April 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v18.i1.pp335-342

Abstract

A compact and simple structure antenna for wearable application at 2.4 GHz is presented and studied. The felt fabric material is used in this paper due to its suitable thickness and dielectric constant. This material provides high flexibility which can be easily worn on a body and incorporated into our daily clothes. In view of the fact that the design will work on a moving person, therefore a circularly polarized antenna is desired to optimize the off-body communication link. The Cicular Polarization (CP) is achieved by introducing truncated corners on the patch. The antenna size is 60 × 60 × 2 mm3. The Axial Ratio (AR), the Front to Back Ratio (FRB) and the realized gain are 0.96 dB, 10.5 dB, and 4.62 dB, respectively indicating a good performance of the antenna at the desired frequency. Furthermore, the antenna was investigated when operating near the body. The obtained result shows that the design has performance similar to the case of free space. This is due to the present of the full ground plane that acts as a shielding between the antenna and body. Finally, the Specific Absorption Rate (SAR) is carried out and showed that the antenna has a level less than the limits fixed by the FCC standard. Therefore, the antenna could be useful for wearable applications.
Unorthodox technique in sensing with the metamaterial-based resonator sensor at millimetre frequencies Suhail Asghar Qureshi; Zuhairiah Zainal Abidin; Huda A. Majid; Adel Y. I. Ashyap; Bashar A. F. Esmail
Indonesian Journal of Electrical Engineering and Computer Science Vol 31, No 2: August 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v31.i2.pp785-793

Abstract

A metamaterial-based resonator is presented in this paper for liquid-sensing applications. The designed sensor operates at millimetre-wave (mm-w) frequencies, and it can characterise the samples that may possess identical characteristics. This paper relies on the extracted permittivity of the structure in the characterisation of the samples, mainly liquids. The sensor requires a very small amount of samples for sensing and it is used in distinguishing oil, ethanol, methanol, glycerol and water. A shift in the resonance frequency of about 200 MHz per unit increase in the epsilon value of samples was achieved. The oil sample showed the lowest value in the extracted permittivity value, while water showed the nearest to zero extracted permittivity. This relationship of variation in extracted permittivity parameter with the change in the sample’s epsilon value is found to be linear and reliable regardless of the change in thickness of the sample.