Now showing 1 - 6 of 6
  • Publication
    Green Nanocomposite-Based metamaterial electromagnetic absorbers: Potential, current developments and future perspectives
    ( 2020)
    Nurul Fatihah Nabila Yah
    ;
    ;
    Mohdfareq Abdulmalek
    ;
    Soh Ping Jack
    ;
    R. Badlishah, Ahmad
    ;
    ;
    Lee Yeng Seng
    ;
    Mohd Haizal Jamaluddin
    ;
      17  17
  • Publication
    Design of multiple-layer microwave absorbing structure based on rice husk and carbon nanotubes
    ( 2017-01-01)
    Lee Yeng Seng
    ;
    ; ;
    Mohamed Fareq AbdulMalek
    ;
    Kok Yeow You
    ;
    ;
    Muhammad Ezanuddin Abdul Aziz
    This paper presents a multiple-layered microwave absorber using rice husk and carbon nanotube composite. The dielectric properties of each layer composite were measured and analysed. The different layer of microwave absorber enables to control the microwave absorption performance. The microwave absorption performances are demonstrated through measurements of reflectivity over the frequency range 2–18 GHz. An improvement of microwave absorption <−20 dB is observed with respect to a high lossy composite placed at bottom layer of multiple layers. Reflectivity evaluations indicate that the composites display a great potential application as wideband electromagnetic wave absorbers.
      4  31
  • 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.
      48  1
  • Publication
    Electrically tunable Left-Handed textile metamaterial for microwave applications
    ( 2021)
    Kabir Hossain
    ;
    ; ;
    Ping Jack Soh
    ;
    Mohd Haizal Jamaluddin
    ;
    Samir Salem Al-Bawri
    ;
    ;
    R. Badlishah, Ahmad
    ;
    ; ;
    Nitin Saluja
    An electrically tunable, textile-based metamaterial (MTM) is presented in this work. The proposed MTM unit cell consists of a decagonal-shaped split-ring resonator and a slotted ground plane integrated with RF varactor diodes. The characteristics of the proposed MTM were first studied independently using a single unit cell, prior to different array combinations consisting of 1 × 2, 2 × 1, and 2 × 2 unit cells. Experimental validation was conducted for the fabricated 2 × 2 unit cell array format. The proposed tunable MTM array exhibits tunable left-handed characteristics for both simulation and measurement from 2.71 to 5.51 GHz and provides a tunable transmission coefficient of the MTM. Besides the left-handed properties within the frequency of interest (from 1 to 15 GHz), the proposed MTM also exhibits negative permittivity and permeability from 8.54 to 10.82 GHz and from 10.6 to 13.78 GHz, respectively. The proposed tunable MTM could operate in a dynamic mode using a feedback system for different microwave wearable applications.
      4  22
  • Publication
    A dielectric resonator antenna with enhanced gain and bandwidth for 5G applications
    ( 2020-02-01)
    Ali I.
    ;
    Jamaluddin M.H.
    ;
    Gaya A.
    ;
    In this paper, a dielectric resonator antenna (DRA) with high gain and wide impedance bandwidth for fifth-generation (5G) wireless communication applications is proposed. The dielectric resonator antenna is designed to operate at higher-order TExδ15 mode to achieve high antenna gain, while a hollow cylinder at the center of the DRA is introduced to improve bandwidth by reducing the quality factor. The DRA is excited by a 50Ω microstrip line with a narrow aperture slot. The reflection coefficient, antenna gain, and radiation pattern of the proposed DRAs are analyzed using the commercially available full-wave electromagnetic simulation tool CST Microwave Studio (CST MWS). In order to verify the simulation results, the proposed antenna structures were fabricated and experimentally validated. Measured results of the fabricated prototypes show a 10-dB return loss impedance bandwidth of 10.7% (14.3−15.9GHz) and 16.1% (14.1−16.5 GHz) for DRA1 and DRA2, respectively, at the operating frequency of 15 GHz. The results show that the designed antenna structure can be used in the Internet of things (IoT) for device-to-device (D2D) communication in 5G systems.
      3  16
  • Publication
    Green Nanocomposite-Based Metamaterial Electromagnetic Absorbers: Potential, Current Developments and Future Perspectives
    ( 2020-01-01)
    Yah N.F.N.
    ;
    ;
    Soh Ping Jack
    ;
    Abdulmalek M.
    ;
    ; ;
    Seng, Lee Yeng
    ;
    Jamaluddin M.H.
    ;
    The use of the natural materials instead of conventional materials as electromagnetic absorbers promotes environmental sustainability, cost-effectiveness, and ease of accessibility. Furthermore, these materials may also be designed as absorbers and as reinforcements in building materials in a lightweight form. The absorbing ability of composite materials can be customized based on the chosen fillers. Specifically, magnetic and dielectric fillers can be incorporated to improve the absorption of a composite material compared to traditional materials. This work aims to review recent developments of electromagnetic absorbers enabled by nanocomposites, metamaterial and metasurface-based, as well as green composite alternatives. First, the background concepts of electromagnetic wave absorption and reflection will be presented, followed by the assessment techniques in determining electromagnetic properties of absorbing materials. Next, the state-of-the-art absorbers utilizing different materials will be presented and their performances are compared. This review concludes with a special focus on the future perspective of the potential of metamaterial based nanocellulose composites as ultrathin and broadband electromagnetic absorbers.
      40  2