Now showing 1 - 10 of 89
  • Publication
    Optimized Intelligent Classifier for Early Breast Cancer Detection Using Ultra-Wide Band Transceiver
    ( 2022-11-01)
    Halim A.A.A.
    ;
    ; ; ; ; ;
    Abd Rahman M.A.
    ;
    Zamin N.
    ;
    Mary M.R.
    ;
    Khatun S.
    Breast cancer is the most common cancer diagnosed in women and the leading cause of cancer-related deaths among women worldwide. The death rate is high because of the lack of early signs. Due to the absence of a cure, immediate treatment is necessary to remove the cancerous cells and prolong life. For early breast cancer detection, it is crucial to propose a robust intelligent classifier with statistical feature analysis that considers parameter existence, size, and location. This paper proposes a novel Multi-Stage Feature Selection with Binary Particle Swarm Optimization (MSFS–BPSO) using Ultra-Wideband (UWB). A collection of 39,000 data samples from non-tumor and with tumor sizes ranging from 2 to 7 mm was created using realistic tissue-like dielectric materials. Subsequently, the tumor models were inserted into the heterogeneous breast phantom. The breast phantom with tumors was imaged and represented in both time and frequency domains using the UWB signal. Consequently, the dataset was fed into the MSFS–BPSO framework and started with feature normalization before it was reduced using feature dimension reduction. Then, the feature selection (based on time/frequency domain) using seven different classifiers selected the frequency domain compared to the time domain and continued to perform feature extraction. Feature selection using Analysis of Variance (ANOVA) is able to distinguish between class-correlated data. Finally, the optimum feature subset was selected using a Probabilistic Neural Network (PNN) classifier with the Binary Particle Swarm Optimization (BPSO) method. The research findings found that the MSFS–BPSO method has increased classification accuracy up to 96.3% and given good dependability even when employing an enormous data sample.
  • Publication
    Design of a 1-Bit Programmable Coding Unit Cell Beamforming Metasurface
    ( 2023-01-01)
    Johari S.
    ;
    Amri M.M.
    ;
    ; ; ;
    Rahim M.K.A.
    Traditional phased array antennas rely on costly phase shifters to steer beams by manipulating the phase of induced currents in each antenna element. In this study, we introduce a 1-bit coding metasurface as an alternative to traditional phased array antennas for beam control and modulation of electromagnetic waves. The metasurface operates at 5.8 GHz and consists of digitally controlled unit cells, each incorporating a pin diode. These diodes enable binary coding states of "1" and "0" with a significant 180-degree phase difference. The unit cell, with a dimension of 0.81λ x 0.81λ, comprises two metal patches separated by the pin diode on an FR-4 substrate. Simulation results demonstrate the distinct behavior of the metasurface, with the off-state exhibiting a reflection amplitude response of 1.8dB and the on-state showing a reduced amplitude due to on-resistance. The far-field patterns obtained from the simulations clearly indicate a 90-degree change in the radiation pattern between bit "0" and bit "1." This innovative design offers a cost-effective solution for beam control and versatile electromagnetic wave modulation, making it suitable for various applications, including beamforming in radar and communication systems.
  • Publication
    Reconfigurable beam steering parasitic patch antenna with embedded PIN diode
    The work described in this dissertation focuses on the reconfigurable beam steering antenna functionality for point-to-multipoint wireless communication application. This concept helps to reduce the antenna size, cost, and gives more flexibility for a customer premises equipment (CPE) to be operated in several modes. The studies involve the microstrip patch antenna of low profile, low cost, ease of fabrication and easy to be integrated with other RF components. Beam steering/forming antenna is useful in the rapid growth of the wireless communication system such as Wireless Interoperability Microwave Access (WiMAX) and Long Term Evolution (LTE). This dissertation introduces the preliminary investigation on a single element reconfigurable patch antenna which uses PIN diodes as the switching mechanism. With that, reconfigurable pattern of an antenna is studied in depth. Then, the dissertation more focused on spiral reconfigurabe beam antenna with aperture coupled feed technique designed on two Taconic substrate with similar dielectric constant of 2.2. It is discovered that such parasitic and mutual coupling technique is able to steer the radiating beam to four different angles of +176°, +10°, -1° and -12°. Therefore, this dissertation continues on designing another steerable beam antenna that uses similar technique of parasitic array and mutual coupling method. (Parasitic element is the element that undirectly excited by the RF induced current. While mutual coupling exists due to the interaction between the adjacent element). The mutual coupling effect has been introduced by the Yagi-Uda antenna in realizing the beam directional ability. Adopting the Yagi-Uda principle, this dissertation has proposeda novel five-element patch antenna (single-fed driven element and four parasitic elements) in achieving the beam steering at ϕ of 0°, 45°, 135°, 225° and 315°. Two reconfigurable antenna prototypes are implemented with embedded RF switching technique with two different types of RF PIN diodes, namely; BAR-5002V and HPND-4005. The first prototype integrates the BAR-5002V on the second substrate layer known as stacked FPPA. While, the second design integrates the HPND-4005 on the similar radiating layer denotes as single layer FPPA. The FPPA is developed by a driven element encircled by four parasitic elements. The driven element is induced by the coaxial feed technique. Each of the parasitic element is positioned in such a way that optimum coupling effect is produced from the arrangement of the driven element and the specified shorting pin locations. Both prototype have achieved an approximate high gain of 8 dBi at all desired phi directions. Measured and simulated results with a very good agreement are obtained, thus the proposed concepts considered valid.
  • Publication
    Design of Compact UHF-RFID Tag Antenna with Meander Line Technique
    ( 2020-03-20)
    Fazilah A.F.M.
    ;
    ;
    Zakaria A.
    ;
    ;
    Ibrahim M.F.
    ;
    Osman M.N.
    ;
    Yaasin M.N.
    ;
    Malhotra S.
    ;
    Rahim H.A.
    In this paper, a compact UHF RFID tag antenna that can operate at Malaysia UHF RFID frequency (860 MHz - 960MHz) is proposed. The antenna with a common geometry structure without any shorting pin consists of 90degree angled line (meander line) and double T-match structure. The proposed antenna has been designed and simulated using CST Simulation software. The proposed tag antenna design shows a good performance in terms of size, gain and impedance with a dimension of 36 mm 25 mm 1.6 mm. The simulated gain of antenna obtained is -0.135 dB at 910 MHz with 19 MHz bandwidth.
  • Publication
    A dual band antenna design for future millimeter wave wireless communication at 24.25 GHz and 38 GHz
    ( 2017-10-10)
    Daud N.N.
    ;
    ; ; ;
    Sapabathy T.
    ;
    Mohd Nizam Osman
    ;
    Yassin M.N.M.
    ;
    Kamarudin M.R.
    This paper proposes a dual band antenna for future millimeter wave wireless communication. The performance of this dual band antenna is analyzed in term of reflection coefficient when some of the length of the patch antenna was adjustable, overall gain and total efficiency for both frequencies respectively. The size of this presented patch antenna is 4.9 × 7.6 mm2. The dual band antenna was fabricated on a RTRogers5880 with a dielectric constant of £=2.2 and thickness of the substrate is 0.127 mm. The simulated result obtained the reflection coefficient as a requirement of the antenna which is not less than -10 dB for 24.25 GHz and 38 GHz that capable to cover 5G applications. The proposed antenna has achieved a maximum gain up to 5.5 dBi and 4.5 dBi at desired frequencies respectively. All design and simulation are carried out using CST Microwave Studio software. The proposed antenna design could be suitable to be applied as a device to the 5G wireless system.
  • Publication
    Negative Index Metamaterial-Based Frequency-Reconfigurable Textile CPW Antenna for Microwave Imaging of Breast Cancer
    ( 2022-02-01)
    Hossain K.
    ;
    ; ;
    Lee S.H.
    ;
    Rahman K.S.A.
    ;
    Kamarudin M.R.
    In this paper, we report the design and development of a metamaterial (MTM)-based directional coplanar waveguide (CPW)-fed reconfigurable textile antenna using radiofrequency (RF) varactor diodes for microwave breast imaging. Both simulation and measurement results of the proposed MTM-based CPW-fed reconfigurable textile antenna revealed a continuous frequency re-configuration to a distinct frequency band between 2.42 GHz and 3.2 GHz with a frequency ratio of 2.33:1, and with a static bandwidth at 4–15 GHz. The results also indicated that directional radiation pattern could be produced at the frequency reconfigurable region and the antenna had a peak gain of 7.56 dBi with an average efficiency of more than 67%. The MTM-based reconfigurable antenna was also tested under the deformed condition and analysed in the vicinity of the breast phantom. This microwave imaging system was used to perform simulation and measurement experiments on a custom-fabricated realistic breast phantom with heterogeneous tissue composition with image reconstruction using delay-and-sum (DAS) and delay-multiply-and-sum (DMAS) algorithms. Given that the MWI system was capable of detecting a cancer as small as 10 mm in the breast phan-tom, we propose that this technique may be used clinically for the detection of breast cancer.
  • Publication
    Design of a Compact Reconfigurable Antenna with Hybrid Polarization and Frequency Control for Geofencing Application
    A frequency reconfigurable antenna for location monitoring is proposed. The antenna developed can be reconfigured at two frequencies with suitable polarization and radiation pattern which designed for geofencing application, thus it either can operate at 1.575 GHz band or 2.45 GHz band. The expected outcome of this work is that when the user is within the geo-fence area it will use WIFI, while when the user exits the geo-fence area, GPS application will be selected. With the use of two switches, the antenna can operate either at band from 2.335 GHz to 2.593 GHz for S11< -10 dB and from 1.546 GHz to 1.588 GHz at S11 <-6 dB. The axial ratio results of less than 3 dB is achieved at 1.575 GHz with a bandwidth of 20 MHz.
  • Publication
    Compact ultra-wideband monopole antenna loaded with metamaterial
    ( 2020-02-01)
    Al-bawri S.S.
    ;
    Goh H.H.
    ;
    Islam M.S.
    ;
    Wong H.Y.
    ;
    Jamlos M.F.
    ;
    Narbudowicz A.
    ;
    ; ;
    Khan, Rizwan D.
    ;
    Islam M.T.
    A printed compact monopole antenna based on a single negative (SNG) metamaterial is proposed for ultra-wideband (UWB) applications. A low-profile, key-shaped structure forms the radiating monopole and is loaded with metamaterial unit cells with negative permittivity and more than 1.5 GHz bandwidth of near-zero refractive index (NZRI) property. The antenna offers a wide bandwidth from 3.08 to 14.1 GHz and an average gain of 4.54 dBi, with a peak gain of 6.12 dBi; this is in contrast to the poor performance when metamaterial is not used. Moreover, the maximum obtained radiation efficiency is 97%. A reasonable agreement between simulation and experiments is realized, demonstrating that the proposed antenna can operate over a wide bandwidth with symmetric split-ring resonator (SSRR) metamaterial structures and compact size of 14.5 × 22 mm2 (0.148 λ0 × 0.226 λ0) with respect to the lowest operating frequency.
  • Publication
    A Fuzzy-Based Angle-of-Arrival Estimation System (AES) Using Radiation Pattern Reconfigurable (RPR) Antenna and Modified Gaussian Membership Function
    ( 2019-01-01)
    Jais M.I.
    ;
    ; ; ;
    Jamaluddin M.H.
    ;
    Kamarudin M.R.
    ;
    Ehkan P.
    ;
    Murukesan Loganathan L.
    ;
    Soh P.J.
    Angle-of-arrival (AOA) estimation is an important factor in various wireless sensing applications, especially localization systems. This paper proposes a new type of AOA estimation sensor node, known as AOA-estimation system (AES) where the received signal strength indication (RSSI) from multiple radiation pattern reconfigurable (RPR) antennas are used to calculate the AOA. In the proposed framework, three sets of RPR antennas have been used to provide a coverage of 15 regions of radiation patterns at different angles. The salient feature of this RPR-based AOA estimation is the use of Fuzzy Inferences System (FIS) to further enhance the number of estimation points. The introduction of a modified FIS membership function (MF) based on Gaussian function resulted in an improved 85% FIS aggregation percentage between the fuzzy input and output. This later resulted in a low AOA error (of less than 5%) and root-mean-square error (of less than 8°).
  • Publication
    Reconfigurable pattern patch antenna for mid-band 5G: A review
    ( 2022-01-01)
    Isa S.R.
    ;
    ; ;
    Nebhen J.
    ;
    Kamarudin M.R.
    ;
    ;
    Abbasi Q.H.
    ;
    ; ;
    Soh Ping Jack
    New requirements in communication technologies make it imperative to rehash conventional features such as reconfigurable antennas to adapt with the future adaptability advancements. This paper presents a comprehensive review of reconfigurable antennas, specifically in terms of radiation patterns for adaptation in the upcoming Fifth Generation (5G) New Radio frequency bands. They represent the key of antenna technology for materializing a high rate transmission, increased spectral and energy efficiency, reduced interference, and improved the beam steering and beam shaping, thereby land a great promise for planar antennas to boost the mid-band 5G. This review begins with an overview of the underlying principals in reconfiguring radiation patterns, followed by the presentations of the implemented innovative antenna topologies to suit particular advanced features. The various adaptation techniques of radiation pattern reconfigurable planar antennas and the understanding of its antenna design approaches has been investigated for its radiation pattern enhancement. A variety of design configurations have also been critically studied for their compatibilities to be operated in the mid-band communication systems. The review provides new insights on pattern reconfigurable antenna where such antennas are categorized as beam steering antenna and beam shaping antennas where the operation modes and purposes are clearly investigated. The review also revealed that for mid-band 5G communication, the commonly used electronic switching such as PIN diodes have sufficient isolation loss to provide the required beam performance.