Now showing 1 - 10 of 109
  • 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
    Two layered 2 × 1 Koch curve patch array antenna with suspended air gap effect for wireless LAN applications
    ( 2017-11-20)
    Abdulmalek M.
    ;
    Nornikman H.
    ;
    Al-Khatib O.
    ;
    Badrul Hisham Ahmad
    ;
    Abdulaziz N.
    ;
    Mohamad Zoinol Abidin Abd Aziz
    ;
    ;
    Ann N.Y.
    ;
    Shen J.Y.L.
    ;
    Salman N.
    ;
    Razak N.M.
    ;
    Bakar H.A.
    This paper proposed a two layered 2 × 1 Koch Curve patch array antenna design with suspended air gap technique for Wireless Local Area Network (WLAN) application of 2.4 GHz resonant frequency. This proposed patch antenna is using two FR-4 substrate layers with dielectric constant, εr = 4.4 and the electrical conductivity tangent loss, tanΔ = 0.019. It is using the suspended air gap technique between two layers for enhancement effect of antenna gain from 4.89 dB to 5.18 dB. At the upper part of substrate, it consists a two feeding networks that connected the two patch of Koch Curve array patch. Beside antenna gain, this technique also improves the bandwidth and return loss of the antenna. It also contains a Koch Curve array structure at the patch part and have a full ground of copper at the back. This Koch Curve is design based on the basic equilateral triangle with three iteration steps. For the first iteration step, it be made up of the equilateral triangular shaped while the second iteration are added with mirror design of equilateral triangular to create a six segment of star-shaped. For the third iteration step, the equilateral triangle with the length base on previous iteration step is constructed on top of the side line of the base triangle. This third iteration step of the Koch Curve effect the reduction size of the patch antenna from 100 mm × 100 mm to only 90 mm × 60 mm. The return loss performance at resonant frequency 2.4 GHz is −32.735 dB.
  • Publication
    Minimum Power Allocation Cooperative Communication based on Health-Care WBAN
    ( 2020-03-20)
    Hammood D.A.
    ;
    Alkhayyat A.
    ;
    ;
    Energy is limited resource in the Wireless Body Area Network (WBAN). Finding optimal and minimum required transmission power that can achieve a certain level of utility while utilizing as little power for transmission as possible plays an important role in reducing energy consumption. In this paper, we found the required transmission power of four transmission modes: the direct transmission mode, the dual-hop transmission mode, and two incremental cooperative transmission modes with Rayleigh channel fading.
  • Publication
    A multilayered acoustic signal generator for low power energy harvesting
    This paper presents the design and analysis of a multilayer cantilever to harvest vibration energy by generating acoustic signal. To do so, a five layer configuration is used to design the cantilever. Lead Zirconate Titanate (PZT-8), Stainless Steel 405 Annealed, Aluminum and Zinc Oxide are used to develop the layers. Water is used as the medium to analyze the sound propagation pattern. Sound Pressure Level, displacements and electric potential of the cantilever are analyzed along with other parameters. From the results, it is evident that, the proposed cantilever can propagate sound within a range of 78.7 dB to 73.4 dB in a 50 mm spherical distance.
  • Publication
    A brief review of the EMF interaction: Metal implantation and biological tissues
    In analyzing the near field for a device, such as a mobile phone used in close proximity to tissues, it is difficult to predict the electromagnetic field (EMF) and other characteristics, since certain parts of the mobile phone scatter and reflect the EMF. Moreover, the absorption of EMF in the lossy tissues mitigates as the radio frequency (RF) energy is absorbed by the tissue. In order to minimize the heating effect on human tissue caused by this absorption of RF energy by the human body, all communications equipment (CE) must comply with the guidelines that established the maximum power output of devices. Though RF emissions from CE are carefully measured, the probability exists that the RF characteristics are reformed somewhat when tissue that illuminated by RF energy embedded with implant, thereby increasing the specific absorption rate (SAR). The SAR is the fundamental metric for specifying RF absorption by tissues and it can be calculated at any location in the tissue.
  • Publication
    Dielectric spectroscopy technique for carbohydrate characterization of fragrant rice, brown rice and white rice
    ( 2017-11-20) ;
    Kok Yeow You
    ;
    Lee KimYee
    ;
    Abbas Z.
    ;
    ; ; ;
    Lee Y.S.
    This study was conducted to investigate the feasibility of microwave dielectric spectroscopic technique in characterizing commercial rice due to different level of moisture content. There are some unethical rice industry runner mixes good qualities of rice which can be sold at high price with low cost and quality of rice to maximize profit. It causes fraudulency in business and great lost in term of money to nation who take rice as staple food. It happens frequently in Asian country which is active in agricultural activities. This technique is implemented using Keysight E8362B network analyzer in conjunction with an Keysight 85070E dielectric probe ranging from 200 MHz to 10 GHz. The samples of study are commercially available at market, namely fragrant rice, white rice, and brown rice, respectively. These are the popular and favorite rice for Malaysian due its delicacy and affordable price. Nutrient level for fragrant rice, white rice, and brown rice in terms of protein, moisture, carbohydrate and fat are different and unique. It leads to various electromagnetic responses toward frequency. Dielectric and reflection measurement were conducted to characterize these rice. The presence of polar and non-polar molecules in nutrient of rice causes variation of dielectric and reflection behavior over the operating frequency range.
  • Publication
    A modified antipodal vivaldi antenna (AVA) with elliptical slotting edge (ESE) for ultra-wideband (UWB) applications
    ( 2017-11-20)
    Nornikman H.
    ;
    Abdulmalek M.
    ;
    Ahmad B.H.
    ;
    Al-Khatib O.
    ;
    Aziz M.Z.A.A.
    ;
    ;
    Soon Y.Y.
    ;
    Muslimah M.S.
    ;
    Syazwany R.
    ;
    Salimi H.I.
    ;
    Amirul M.Y.
    ;
    Azizi M.S.N.
    As the demand of UWB system increases nowadays, several types of hybrid technique on antenna design are studied, modified, and proposed for UWB applications. In this work, an enhanced performance of modified antipodal Vivaldi antenna (AVA) for targeting ultrawideband (UWB) frequency range between 2.17 GHz and 10.6 GHz has been proposed. This proposed UWB antenna is using FR-4 substrate with dielectric constant, εr = 4.4 and the electrical conductivity tangent loss, tanΔ = 0.019. This antenna design is based on the modified from the dual exponential tapered slot antenna (DETSA) with varying of the exponential flares design for obtain the best return loss of the antenna within the frequency bandwidth of the UWB. It has two exponential flares that follow the characteristic of exponential curve. Next, an elliptical slotting edge (ESE) with fixed horizontal radius and varied vertical radius is implemented to the antenna which effectively increases the performance of the antenna at lower frequencies. These modifications are done without changing the antenna size, which is 70 mm × 90 mm in dimension, which is approximately 0.5λ × 0.6λ, where λ is the wavelength of 2 GHz. The effects of the parameters of the antenna characteristic are also studied. In this case, the parametric study on varying distance between elliptical slots, Ks. It shows that, the higher value of Ks will effect to shift to the resonant frequency and increase the return loss of the antenna. At 9.104 GHz of resonant frequencies, it shows of the best return loss of 48.809 dB. Rather than that, the side lobe levels of the radiation pattern of the antenna are reduced in the lower frequencies.
  • Publication
    SAR for wearable antennas with AMC made using PDMS and textiles
    ( 2017-11-10)
    Muhammad Nazrin Ramli
    ;
    Soh Ping Jack
    ;
    ;
    Mohd Faizal Jamlos
    ;
    Fatin Nabilah Giman
    ;
    Ezzaty Faridah Nor Mohd Hussin
    ;
    Herwansyah Lago
    ;
    Emmanuel Van Lil
    Besides the radiation and reflection performance of wearable antennas, arguably one of the most important parameters is their Specific Absorption Rate (SAR). This work aims to evaluate SAR for wearable antennas integrated with Artificial Magnetic Conductor (AMC) plane made using different material categories - textiles and a flexible polymer,. Two types of textiles, felt and ShieldIt Super are used to build the first, textile-based antenna, while polydimethylsiloxane (PDMS) and the fluidic metal eutectic gallium indium alloy (EGaIn) are used to build the second, polymer-based antenna. Both materials are chosen due to their flexibility conformity to the human body, thus providing comfort to users. Despite the SAR for both antenna types did not exceed the European regulatory limits of 2 W/kg averaged over 10g of tissues; there are considerable differences between them.
  • Publication
    Parametric studies on effects of defected ground structure (DGS) for dual band bandstop microstrip filter
    A dual-band bandstop microstrip filter is proposed and designed by using microstrip resonator with Defected Ground Structure (DGS). The DGS are placed in the ground plane to obtain high attenuation of the bandstop filter response. The proposed is designed by using R04003C printed circuit board with dimension of 38 mm x 20 mm. Simulated result shows an insertion loss of -12.31 dB, a return loss at -1.75 dB for center frequency at 2.4 GHz and insertion loss of -22.93 dB, a return loss of -0.78 dB for center frequency at 5.8 GHz The results of simulated in different parameters of DGS is analysed and discussed.
  • Publication
    Decagonal c-shaped csrr textile-based metamaterial for microwave applications
    ( 2022-01-01)
    Hossain K.
    ;
    ; ;
    Soh Ping Jack
    ;
    Al-Bawri S.S.
    ;
    Osman M.N.
    ;
    ;
    Torrungrueng D.
    ;
    Akkaraekthalin P.
    This paper introduces a decagonal C-shaped complementary splitring resonator (CSRR) textile-based metamaterial (MTM). The overall size of the proposed sub-wavelength MTM unit cell is 0.28λ0 ×0.255λ0 at 3 GHz. Its stopband behaviour was first studied prior analysing the negative index properties of the proposed MTM. It is worth noting that in this work a unique way the experiments were completed. For both simulations andmeasurements, the proposed MTM exhibited negative-permittivity and negative-refractive index characteristics with an average bandwidth of more than 3 GHz (considering 1.7 to 8.2 GHz as the measurements were carried out within this range). In simulations, the MTM exhibited negative-permittivity properties within the range of 1.7 to 7.52 GHz and 7.96 to 8.2 GHz; and negative-refractive index from 1.7 to 2.23 GHz and 2.33 to 5.09 GHz and 5.63 to 7.45 GHz. When measured from 1.7 to 8.2 GHz, negative-permittivity and negative-refractive index characteristics are exhibited throughout an average bandwidth of more than 3 GHz. Similarly, the transmission coefficient attained in simulations and measurements indicated about 3 GHz of bandwidth, from 1.7 to 3.88 GHz and from 6.68 to 7.4 GHz. The satisfactory agreement between simulations and experiments indicates the potential of the proposed MTM for microwave applications.