AHM Zahirul Alam
International Islamic University Malaysia

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Effects of Inter-Element Spacing and Number of Elements on Planar Array Antenna Characteristics Noor Hidayah Muhamad Adnan; Islam Md. Rafiqul; AHM Zahirul Alam
Indonesian Journal of Electrical Engineering and Computer Science Vol 10, No 1: April 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v10.i1.pp230-240

Abstract

Planar array antenna is seen as one of the innovative solutions of massive MIMO and 5G networks since they provide directive beams. In this paper, planar array antenna with square and rectangular arrangements based on 2 x 2 antenna elements as one subarray was proposed. Then, array factor for the the planar array antenna with up to 64 antenna elements was calculated to analyze the effects of inter-element spacing and number of elements on the antenna characteristics. Higher values of inter-element spacing contributed to higher number of side lobes, narrower main lobe, higher directivity and lower half power beamwidth (HPBW). Inter-element spacing equals to 0.5λ was found to be the most suitable value for planar array antenna design based on the analysis. Meanwhile, higher number of antenna elements increased the value of directivity of the planar array with narrower HPBW. Therefore, there is a tradeoff between directivity and HPBW in designing planar array antenna for massive MIMO application.        
Recognition of Metal Objects inside Wall using Antipodal Vivaldi Antenna Faraz Ahmed Shaikh; Sheroz Khan; Zarimin Zaharudin; AHM Zahirul Alam; Farah Diyana Bt. Abdul Rahman; Khairayu Bt. Badron; Dominique Baillargeat; Mashkuri Bin Yaacob; Zeeshan Shahid
Indonesian Journal of Electrical Engineering and Computer Science Vol 11, No 1: July 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v11.i1.pp27-35

Abstract

This paper present a recognition technique of metal placed inside and between two walls. A unique scheme of recognition of metallic objects through Ultra Wide Band (UWB) Modified Antipodal Vivaldi Antenna (MAVA) frequency range of (3.1GHz to 10.6 GHz) is presented in this paper.The working mechanism of detection system based on Time Domain Reflectrometry (TDR) using through wall imaging (TWMI). A very small duration pulses generated by Vector Network Analyzer (VNA) which are used for illuminate the wall.The analysis of a system under UWB antenna probe array. The simulation results of MAVA have given an enormous potential of penetration, in order to recognize concealed metal objects with fine precision, proving a smart development in the detection system technology. The improvement of resolution in an image, special filters have been developed and implemented. The design and optimization progression is conceded out via CST simulation software for parametric performance assessment of return loss, radiation pattern and directivity.
An Analysis of a Flexible Dry Surface Electrodes Amelia Wong Azman; Muhammad Farhan Azman; Siti Mohd Ariff; Yasir Mohd Mustafah; Huda Adibah Mohd Ramli; AHM Zahirul Alam; Mohamed Hadi Habaebi
Indonesian Journal of Electrical Engineering and Computer Science Vol 10, No 1: April 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v10.i1.pp74-83

Abstract

In the medical field, electrodes are commonly used either to retrieve signals or to conduct current. Most of the off-the-shelf surface electrodes are made from metal or rigid substrates. This paper presents a work on designing a new flexible dry electrodes using poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and silver by means of dispenser printing technology. The polyester cotton fabric was selected as the substrate in this electrode designed. To analyse the new proposed composites of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and silver, different mixtures have been applied.  Results from the experiment show that the conductivity of the proposed flexible electrode is comparable with the commercialized pre-gelled electrode when applied to an electrical stimulator device. Eight out of ten subjects under test described no difference in comfort between the proposed electrodes and pre-gelled electrodes.