Azremi Abdullah Al-Hadi

Azremi Abdullah Al-Hadi
Universiti Malaysia Perlis | unimap · School of Computer and Communication Engineering

D.Sc (Technology) in Radio Engineering

About

197
Publications
63,646
Reads
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1,436
Citations
Introduction
Azremi Abdullah Al-Hadi was born on August 26 in Michigan, United States of America. He received the Master of Science degree in communication engineering from Birmingham University, United Kingdom in 2004 and the Doctor of Science (Technology) degree from Aalto University, Finland in 2013. His current research interests include design and performance evaluation of multi-element antennas, mobile terminal antennas and their user interactions, and wireless propagation.
Additional affiliations
September 2016 - present
Universiti Malaysia Perlis
Position
  • Professor (Associate)
June 2010 - August 2016
Universiti Malaysia Perlis
Position
  • Professor (Associate)
November 2008 - November 2013
Aalto University
Position
  • PhD Student
Description
  • Pursuing doctoral degree in the field of multi-element antennas
Education
November 2008 - November 2013
Aalto University
Field of study
  • Radio Engineering
August 2003 - August 2004
University of Birmingham
Field of study
  • Antennas
July 1999 - April 2002
Universiti Sains Malaysia
Field of study
  • Communication Engineering

Publications

Publications (197)
Conference Paper
In this paper, a method of designing antennas by avoiding crossing between the modes is presented. This is aimed at enhancing antenna bandwidth using ground fragmentation techniques based on the characteristic modes analysis (CMA) approach. A compact and flexible Saxophone antenna and a conventional rectangular microstrip antenna both dimensioned a...
Article
Full-text available
The paper presents the design and analysis of a corona-shaped fractal antenna with a defected ground structure (DGS) for wireless applications. The fractal concept with an inverse patch medium DGS (IPM-DGS) technique is proposed and applied to achieve multi-band frequencies with a high efficiency. The same structure on the top face of the antenna i...
Article
In this paper, the design of a multiband multiple-input multiple-output (MIMO) antenna with frequency and radiation pattern reconfiguration capability in the 5G sub-6 GHz band is presented. Frequency and radiation pattern reconfiguration are enabled on the antenna consisting of two planar inverted-F antenna (PIFA) elements using PIN diodes and DC b...
Article
Full-text available
This paper studies the performance of a 14-element dual-band 5G MIMO antenna with body effect and an antenna selection. The antenna operates in the lower frequency band from 3.10 to 3.85 GHz for 5G bands of LTE 42 and 43, whereas the upper band is from 5.60 to 7.20 GHz for the newly assigned 6 GHz WiFi band. The antenna performance was evaluated in...
Conference Paper
In this paper, a dual band radiation pattern reconfigurable antenna for 5G mobile terminals is presented. Two identical PIFA elements are connected to a PIN diode and feeding port to enable reconfiguration. Copper strips are used as RF switches in this antenna design to represent the actual PIN diodes. The switching of the two PIFA elements in sequ...
Article
Full-text available
This paper presents a hybrid mutual coupling reduction technique applied onto a dual-band textile MIMO antenna for wireless body area network and 5G applications. The MIMO antenna consists of two hexagonal patch antennas, each integrated with a split-ring (SR) and a bar slot to operate in dual-band mode at 2.45 GHz and 3.5 GHz. Each patch is dimens...
Article
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The design of a compact, wideband flexible monopole antenna printed on a flexible Kapton polyimide substrate is presented. The proposed antenna consists of two rhombic elements embedded within a square plane as the radiating element. The wide bandwidth is aimed at alleviating potential performance degradations due to its application in an on‐body e...
Article
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Characteristic modes (CM) can be used to solve many radiation and scattering problems involving fully conducting structures. The basic concept is to use eigenvalues and eigenvectors of the characteristic mode equations of a certain topology, and to use these eigenmode currents to control the radiating structure’s behavior. This is accomplished by u...
Article
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In this paper, a Dual Monopole Frequency Reconfigurable Antenna (DMFRA) for two port Multiple Input Multiple Output (MIMO) Fifth Generation (5G) sub-6 GHz mobile terminal is presented. A combination of dual monopole strips is implemented at a port, respectively to achieve tunable and fixed resonant frequencies. Varactor diode is utilized in this de...
Article
Various decoupling methods were proposed and investigated for multiple-input multiple-output (MIMO) Base Station (BS) systems. These methods can effectively decouple the dual-polarized co-polar signal but fail to decouple the cross-polarized signal, similarly limiting the BS's overall decoupling performance. In this paper, different antenna arrays...
Conference Paper
A compact crown-shaped planar antenna integrated with a 3 × 3 artificial magnetic conductor (AMC) ground is presented for wearable internet of things communications. Simulations were performed using the commercial software FEKO based on two approaches: characteristic mode analysis and the method of moments. This paper aims to optimize the operation...
Article
Full-text available
In this work, the design procedure of a new decoupling network for different antennas is presented for mobile terminals operating in the Sub-1 GHz band (from 0.698 to 0.96 GHz). To evaluate its applicability for different resonant and non-resonant antenna types, two antenna elements have been chosen to be decoupled using the proposed decoupling net...
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Full-text available
This work presents the design and optimization of an antenna with defected ground structure (DGS) using characteristic mode analysis (CMA) to enhance bandwidth. This DGS is integrated with a rectangular patch with circular meandered rings (RPCMR) in a wearable format fully using textiles for wireless body area network (WBAN) application. For this i...
Article
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This paper presents an active mode subtraction method based on the characteristic mode analysis to estimate the forward directivity based on the difference in modal significance curves. This made the optimization of the antenna gain in the design process to be more efficient. To the best of the authors’ knowledge, such method is innovative and prop...
Article
In this paper, the slotted dipole antenna structure is proposed to have four narrowband frequencies with ability to be reconfigured. Narrowband reconfiguration can be achieved by controlling the length of slotted dipole by using switches. The narrowband frequency is to be at 1.8 GHz (GSM), 2.4 GHz (WLAN), 2.6 GHz (4G), and 3.5 GHz (5G) respectively...
Article
Full-text available
This paper investigates the effect of index finger position and distance on the radiated power of 4-element MIMO antenna, operating at 28 GHz. The antenna elements (AEs) are located at the top corner of the user terminal and separated at a distance of half a wavelength. Four different finger placements were investigated, one placement over each AE...
Article
Full-text available
A wearable textile antenna with dual-band and dual-sense characteristics is presented in this work. It operates at the 2.45 GHz band for WBAN and WLAN applications, and at the 1.575 GHz band for Global Positioning System (GPS) applications. An antenna backing based on an artificial magnetic conductor (AMC) plane operating at 2.45 GHz band is introd...
Conference Paper
Full-text available
This paper presents results of maximal ratio combining (MRC) technique of dual-band 4-element MIMO antenna with user's hand in data mode and different placements of antenna elements (AEs) on the chassis. The different placements start from worst case to optimal which is selected to avoid thick tissues of the hand. The dual 5G frequency bands are fr...
Article
A dual band slot dipole antenna made from textile is proposed for Wireless Body Area Network and Wireless Local Area Network applications. The proposed antenna is integrated with an artificial magnetic conductor plane to mitigate backward radiation and reduce Specific Absorption Rate when operated on body. The artificial magnetic conductor plane is...
Article
Full-text available
This paper investigates the performance variation when a different number of antenna elements (AEs) is integrated onto a single MIMO mobile terminal, both in free space and when held in a user hand in data mode. Starting with a minimum of two AEs, this investigation assessed the performance of the MIMO terminal with every additional two AEs (up to...
Conference Paper
In this work, a mutual coupling reduction technique for multiple antennas designed on small chassis is investigated. This technique is based on introducing a meander-shaped defected ground structure (DGS) unit cell located on the top edge in between two planar inverted-F antennas (PIFAs). It functions as a filter to improve the isolation between an...
Article
Full-text available
Two new flexible, single-sided linear-to-circular polarizers based on the square loop unit cells have been proposed in this work. The first uses a flexible Polydimethylsiloxane (PDMS) substrate, whereas the second polarizer is implemented on a felt textile substrate. Both polarizers uses the same ShieldIt textile to form their conducting elements....
Article
A concept of using dual-polarized, three dimensional antenna elements with minimized current distribution on ground plane to reduce the effects of user’s hand on a mobile terminal operating in LTE-U 5G band is proposed. This method which also minimizes mutual coupling (MC) is studied using a structure consisting of two non-identical antenna element...
Article
Full-text available
This paper evaluates the performance of different configurations of MIMO antenna operating in the 5G band with the effect of user's hand in data mode and suggests an optimized configuration to mitigate hand effects. A dual-band four-element MIMO antenna is used. All antenna elements (AEs) are identical planar inverted-F antenna (PIFAs) with a lower...
Article
Full-text available
A wideband microstrip‐based wearable antenna with a fractional bandwidth of 51% is designed using textile materials for wearable applications. The antenna operates between 2 and 3 GHz with low back‐radiation to ensure minimum coupling to the body and reduced electromagnetic power absorption in the human tissue. The behavior microstrip antenna topol...
Article
In this paper, the influence of user’s hand on mobile terminal antenna when it placed approximately on top of Multiple Input Multiple Output radiating element antennas (PIFAs) is studied extensively. The antenna is designed to operate at 5 GHz with 1.5 GHz of -6 dB bandwidth. The effect of user’s hand with different finger positions are studied at...
Article
Full-text available
A printed Yagi-Uda antenna with two closely-spaced driven dipole elements and truncated ground plane is presented for dual-band operation. It is designed on a low-cost FR4 substrate with a dielectric constant 4.6, loss tangent of 0.02, and thickness of 1.6 mm. The dipole, operating in the lower band (centered at 1.8 GHz), is elliptical-bow-tie in s...
Article
Full-text available
This paper is introduced a passive sensor to detect the performance of the structure using three-dimensional (3D) Frequency Selective Surfaces (FSS). The proposed 3D Circular FSS results are proved behave as passive sensor with changing of sensitivity incident angles to be apply in Structural Health Monitoring (SHM) system. Moreover, this 3D Circul...
Article
Full-text available
The use of energy saving glass has become very popular in the modern day building design. This energy saving property is achieved by applying a very thin tin oxide (SnO2) coating on one side of the glass. This coating can provide good thermal insulation to the buildings by blocking infrared rays while being transparent to visible part of the spectr...
Article
Full-text available
The design of directive antenna using Frequency Selective Surface (FSS) superstrate is proposed in this project. The suitable design FSS as superstrate layer is very important to enhance the high directivity and narrow bandwidth on the antenna. By using the FSS layer to design the superstrate layer, there are able to determine the reflection coeffi...
Article
Full-text available
Structural health monitoring (SHM) technologies have attained attention to monitor civil structures. SHM sensor systems have been used in various civil structures such as bridges, buildings, tunnels and so on. However the previous sensor for SHM is wired and encounter with problem to cover large areas. Therefore, wireless sensor was introduced for...
Article
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The capability of the flexible substrate of the frequency selective surface (FSS) to filter out particular frequency is discussed in this paper. A new type of FSS are applied using flexible thin plastic substrate to enhance the performance of the conventional FSS that lacks of flexibility and cannot be used in bending surface. A simulation based in...
Article
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This paper studies the effects of incident wave angular power spectrum (APS) distribution and user hand effect on the envelope correlation coefficient (ECC) of a two-port MIMO antenna operating in the sub 6 GHz LTE-U frequency band. APS of uniform and Gaussian distributions are used with different Gaussian angular spread (AS) values, i.e., 10 • , 3...
Article
In this paper, two multiple input multiple output (MIMO) antennas for Wi-Fi/WLAN mobile applications are proposed. The designed two-port MIMO antennas are made up of planar inverted-F antennas (PIFAs). The antenna elements for both designs are symmetrical and placed on the short-edged corners of the substrate used, FR4. The performance of both ante...
Article
This paper presents the performance evaluation of 2-port MIMO antenna for LTE-U sub 6 GHz band. The evaluation focuses on the effect of user’s hand in a uniform environment and the analysis were carried out on simulation and measurement data of antenna ports. Results show that the highest performance of the design is on the frequency range from 4.5...
Article
In this paper, two multiple input multiple output (MIMO) antennas for Wi-Fi/WLAN mobile applications are proposed. The designed two-port MIMO antennas are made up of planar inverted-F antennas (PIFAs). The antenna elements for both designs are symmetrical and placed on the short-edged corners of the substrate used, FR4. The performance of both ante...
Article
This paper presents a single layered textile-based flexible linear-to-circular polarizing surface. The proposed structure is designed based on a rectangular ring structure for CubeSat application in the S-band. Each unit cell is sized at 0.35λ×0.33λ×0.2λ for operation centered at 2.2 GHz. This unit cell is then multiplied into a 9x10 array to form...
Article
Full-text available
This study is focused on highly coupled multiple antennas with defected ground slot techniques. Two Printed Inverted-F Antenna (PIFA) are positioned at the top edge of chassis symmetrically. Both antennas are operating at low-band Long-Term Evolution (LTE) with center frequency, 829MHz. Rectangular defected ground slot is implemented to reduce the...
Article
This study is focused on highly coupled multiple antennas with defected ground slot techniques. Two Printed Inverted-F Antenna (PIFA) are positioned at the top edge of chassis symmetrically. Both antennas are operating at low-band Long-Term Evolution (LTE) with center frequency, 829MHz. Rectangular defected ground slot is implemented to reduce the...
Conference Paper
Full-text available
A circuit model for a flexible linear-to-circular polarizer is proposed. This linear-to-circular polarizer is designed based on the concept of Frequency Selective Surface (FSS) unit cells on one side and a rectangular-shaped conductive strip (CS) on its reverse side. The overall polarizer is implemented on a felt substrate, whereas ShieldIt Super c...
Article
Full-text available
In this paper, flexible, deployable linear to circular polarizers designed on Polydimethylsiloxane (PDMS) are proposed for the first time to the best of our knowledge. ShieldIt textile is used as the conducting elements of two types of unit elements: a loaded and an unloaded circular element on rear side of the substrate, and a generic rectangular...
Article
Full-text available
This article presents a comprehensive review of mobile terminal antenna researches performed in the past seven years and the current challenges related to the user’s influence on the performance of fifth generation (5G) terminal antennas. The main challenges for designing of mobile terminal antennas are to meet the compact size requirements of buil...
Conference Paper
This paper presents a single layered textile-based flexible linear-to-circular polarizing (LCP) surface. The proposed structure is designed for CubeSat application in the S band, based on a rectangular ring structure. Each unit cell is sized at 0.35λ×0.33λ×0.2λ for operation centered at 2.2 GHz. This unit cell is then multiplied into a 9 x 10 array...
Article
In this paper, the effects of the locations of four dual-band antennas on a mobile terminal chassis are investigated in the vicinity of user’s hand. To perform this study, a dual-band four-port mobile terminal antenna for 5G is designed for operation in between 3.34 and 3.84 GHz (lower band, LB) and 5.15 and 6.52 GHz (upper band, UB), respectively....
Article
Full-text available
A new swastika‐shaped single layered flexible linear‐to‐circular polarizer is proposed for Cube Satellite application in S‐band. The proposed linear‐to‐circular polarizer is designed fully using ShieldIt Super conductive textile on a lightweight felt substrate. Principle of operation is discussed comprehensively with an equivalent circuit model and...
Article
A microstrip patch antenna strain sensor operating at dual frequencies 1.8GHz and 2.4GHz have been designed based on the relation between the resonant frequency and the strain applied to it. Felt substrate with a height of 3mm and dielectric constant of 1.44 and shield conductor are used for the design of this antenna. Testing results show that the...
Article
Full-text available
The effect of users on the efficiency of mobile terminal antennas at 15 GHz, 28 GHz and 60 GHz is studied in this paper. It is performed using three four-element planar arrays. The first operates at 15 GHz with a bandwidth of 0.74 GHz, the second at 28 GHz with a bandwidth of 2.5 GHz and finally the third antenna at 60 GHz with bandwidth of 12.5 GH...
Article
Full-text available
Partial discharge early detection is a major issue in preventative maintenance. This condition is necessary to prevent greater damage in the high voltage system. The PD detection method using UHF sensors has become an attractive method because of its high sensitivity and the ability to detect the PD location. The objective of this study was to inve...
Article
Full-text available
Antenna for a wireless sensor network for early wheel trains damage detection has successfully developed and fabricated with the aim to minimize the risk and increase the safety guaranty for train. Current antenna design is suffered in gain and big in size. For the sensor, current existing sensor only dete