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PHD (ONGOING)



RESEARCH TITLE: RADIO FREQUENCY ENERGY HARVESTING TECHNIQUE AND CHARACTERIZATION USING TEXTILE MATERIAL

Researcher : MUHAMMAD FAIZAL BIN ISMAIL (PhD)  

Abstract : 
This project proposed the Energy Harvesting technique using the electromagnetic energy especially Radio Frequency (RF). Radio wave is ubiquitous in our daily lives in form of signals transmission from TV, Radio, wireless LAN, WiMAX, mobile phone, etc. Communication devices generally have omni-directional and directional antennas that propagate RF energy in most directions, which maximizes connectivity for mobile applications. These electromagnetic signals could be use as the alternative energy by using RF energy harvesting.  The development of energy harvesting system could be increase the development of Green Technology. The energy harvesting system consist of rectifier antenna or rectenna to convert the RF signal to direct current (DC) power, the low pass filter and schottky diode. This energy harvesting system is proposed to fabricate in two types of substrate which are FR-4 board and textile substrate to make it wearable function. The development of compact circular polarization antenna also included to use as a rectenna.



RESEARCH TITLE : ON BODY ABSORPTION COUPLING EFFECTS AND CHARACTERIZATION OF FABRIC ANTENNAS OPERATING AT 2 GHZ TO 12 GHz FREQUENCY BANDS 

Researcher : NORFATIN AKMA BINTI ELIAS (PhD)

Abstract : 
Utilization of textile materials for the wearable antenna applications has been rapid due to the recent miniaturization of wireless devices. Therefore electromagnetic field absorption is becoming an important public concern on potential health hazard. This research project tends to investigate the interaction between electromagnetic field radiated and antenna in terms of the antenna performance and electromagnetic energy absorption by human body in terms of Specific Absorption Rate (SAR). Conventionally, the SAR value is investigated for conventional flat and rigid antenna, however, under an on-body environment it is difficult to keep the textile antenna in a flat condition all of the time. It is therefore necessary to evaluate the textile antenna’s performance and the SAR value under bending and crumpling conditions. Therefore, further intensive study in terms of SAR value and characterization of fabric antenna performance by considering the effect of bending, crumpling, different textile materials, different orientations and different positions on human body will be investigated in this project. In the end of the research, some references and guideline will be proposed in order to improve the current antenna design so that it can eliminate or reduce the effect of human body and works fine under bending or crumpling conditions.



RESEARCH TITLE: RECONFIGURABLE ANTENNA USING ARTIFICIAL MAGNETIC CONDUCTOR

Researcher: RAIMI DEWAN (PhD)

Abstract:
Artificial Magnetic Conductor (AMC) is a class of metamaterial which exhibit the unique characteristic of zero degree reflection phase of Perfect Magnetic Conductor (PMC). AMC consists of an array of unit cells. The use of AMC in antenna design improves various antenna performances such as gain, bandwidth widening, and radiation efficiency with potential miniaturization of the entire antenna structure as compared with the use of Perfect Electric Conductor (PEC) as antenna ground plane. This research involves the design of AMC which its reflection phase can be tuned to various operating frequencies. The tuneable AMC is then incorporated to antenna to achieve to reconfigurability. The application of AMC as reconfigurable mechanism is different with the conventional reconfigurable mechanism which active devices are implemented to the antenna radiating structure itself. Tuneable AMC as reconfigurability mechanism is useful for the achievement of reconfigurable antenna design with improved antenna performances.



RESEARCH TITLE: CHIPLESS RFID SENSOR 

Researcher: MOHD EZWAN JALIL (PhD) 

Abstract:
Radio Frequency Identification (RFID) uses wireless radio frequency system to transfer data for identifying purposes and tracking of tag activities. The RFID system has been implemented for various applications such as in payment systems, access control and asset tracking. The RFID system elements consists of active reader which transmit encoded signal to interrogate the tag, transponder (tags), and subsequently  store the ID information in  integrated circuit that stores and processes the radio-frequency signal. However, production of RFID tag is high in cost due to the presence of Application Specific Integrated Circuit (ASIC) chip. Recently, researchers are focusing in designing a compact and low cost chip less RFID system without the implementation of ASIC. The chip-less RFID system specification is based on the transponder which  uses the electromagnetic properties and design of  various structure to perform data encoding without the need of ASIC chip. There are two types of transponder which are the time domain reflectometry (TDR) such as surface acoustic wave (SAW) tag and spectral signature such as capacitive tuned dipole, space filling curves and LC resonant. However, the a fore mentioned technique  cannot be applied on fully printable material such as bank note and postage stamp due to the piezoelectric nature of SAW tag. The Chip-less RFID tags is based on LC resonant has been proposed using spit-wheel, microstrip open stub and spurline techniques.In this project, the novel flexible and compact chipless RFID are proposed. A new technique based metamaterial has been proposed to represent the bit of ID tag number across the Ultra-wideband frequency. Then, the performances of flexible chipless tags on human body are evaluated



RESEARCH TITLE : TRANSMISSION MODELLING FOR WEARABLE APPLICATION USING DUAL BAND AMC ANTENNA

RESEARCHER : Muhammad Azfar Abdullah (PhD)

Abstract:
Modeling of on-body propagation channels is of paramount importance to those wishing to evaluate radio channel performance for wearable devices in body area networks (BANs). Difficulties in modeling arise due to the highly variable channel conditions related to changes in the user’s state and local environment. This study characterizes these influences by using frequency-domain analysis to examine and model signal characteristics for on-body radio channels in user stationary and mobile scenarios in four different locations: anechoic chamber, open office area, hallway, and outdoor environment. The sheet-like waveguide are used to provide an independent transmission path which can reduce all distortions caused by human body. The proposed AMC waveguide sheet consists of textile substrate with radiating patches and ground plane made of conductive fabric. The flexibility of textile material make it suitable for wearable communications. The transmission characteristics between antennas was studied rigorously in this work. Transmission loss between the antennas have been significantly reduced apart from minimizing the radiation towards human body


RESEARCH TITLE: TWISTED PAIR COPPER CABLE CHARACTERIZATION FOR NEXT GENERATION ACCES IN MALAYSIA

Researcher: AZHARI ASROKIN (PhD)

Abstract:
The purposes of the research is to study and generate a twisted pair copper cable modelling for the future generation of digital subscriber line (DSL) such as G.fast (acronym for Gigabit Fast Access to Subscriber Terminal) with capability of carrying 1Gbps aggregated data on copper cable used by Telekom Malaysia (TM). The research will involve the study on the effect of different cable gauge used by TM, ideal line and non-ideal condition which will be simulated in commercial software such as Matlab and/or CST Microwave Studio. The latest copper technology provided to the customer in Malaysia is the VDSL technology are especially catered to the high rise building which came from the fiber-to-the-curb (FTTC) or fiber-to-the-distribution point (FTTdp) access. The current copper cables deployed to the customer premises in Malaysia are mainly consisting of CAT3 cables which are meant to operate only up to 16MHz. The G.fast standard aims to operate beyond ADSL (< 2MHz) and VDSL (<30MHz) which can be up to 106 or 212 MHz, a study need to be done to characterize the laid copper cable to observe whether the current copper cable can support the new standard. Impairments at higher frequencies are also not yet modelled properly. The two most common impairments occurred in copper network would be the bridge tap and cable imbalance. The research is expected to produce characterized model of the existing TM’s copper cable network within G.FAST new frequency bandwidth from 2 MHz to 250 MHz which include secondary parameters (scattering parameters, gamma and characteristic impedance, Z0) and primary parameters (resistance, inductance, conductance and capacitance). The research will also recommend the ideal cable characterization reference to support G.FAST system which the reference will be used as a pre-qualification standard before any new copper cable network are being deployed or purchased.



RESEARCH TITLE: FREQUENCY RECONFIGUABLE METAMATERIAL ANTENNA

Researcher: ARRAUZAH RAZAK

Abstract:
In the recent years, electromagnetic metamaterials (MTMs) are widely used for antenna applications. MTMs exhibit some specific features which are not found in the conventional material. Thirty years later, Sir John Pendry proposed conductor geometries to form a composite medium which exhibits effective values of negative permittivity and negative permeability. Based on the unique properties of MTMs, many novel antenna applications of these materials have been developed. The use of MTMs could enhance the radiated power of an antenna. Negative permittivity and permeability of these engineered structures can be utilized for making electrically small antenna, highly directive, and reconfigurable antennas. Reconfigurable antennas change polarization, operating frequency, or far-field pattern in order to cope with the changing of system parameters. Antenna reconfiguration is normally achieved in one of three ways; switching parts of the antenna structure in or out using electronic switches, adjusting the loading or matching of the antenna externally, or changing the antenna geometry by mechanical movement. In this research work, two MTMs design approach which is resonant and non-resonant approach will be studied with the aim of achieving a frequency reconfigurable antenna using MTMs structure. Currently, frequency reconfigurable MTMs based on resonant approach is the most approach that used by the researcher. The reconfigurable design will be used Metal-Insulator-Metal (MIM) diode. Computer Simulation Technology (CST) microwave studio will be employed as the simulation tool and measurement of the result will be obtained via Vector network analyzer (VNA) and Anechoic Chamber.

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