Now showing 1 - 10 of 19
  • Publication
    Design of Passive RFID Tag Using Frequency Selective Surface with Polarization Insensitive
    ( 2023-10-06) ;
    Ibrahim N.A.
    ;
    ; ;
    Abdul Aziz M.E.
    RFID is not a new technology. It has been applied in various industries such as for wearable applications. Common RFID tags especially for those that have been designed and are available are not independent of the incident receiver angle. Numerous wearable antennas on the market are only designed for a certain received angle. For example, a wearable RFID antenna is used in medical as a pulse reading detector. If the patient makes any movement, the patient's pulse reading is no longer accurate or there may be no pulse reading. Hence, the purpose of this project is to design and RFID antennas using Frequency Selective Surface, FSS for wearable applications that are independent towards the incident angle and small in size. In this project, several antennas design with Frequency Selective Surface (FSS) is proposed. The design for this antenna is round, square, and hexagonal. This antenna has an operating frequency from 2.4 GHz to 5.8GHz, bandwidth efficiency> 50%, dielectric constant 1.30, independent incident angle up to 60 degrees, and has a high gain of around 2 to 3dB.
  • Publication
    Gain Enhancement of CPW Antenna for IoT Applications using FSS with Miniaturize Unit Cell
    ( 2021-07-26) ; ; ;
    Azhari M.S.B.A.
    ;
    Jiunn N.K.
    Wireless connectivity is a critical enabler for many IoT applications. Antennas are often required to be installed inside the device cover, which usually occurs in small sizes with optimal performance. On the other hand, a suitable antenna should also have high efficiency, gain and adequate bandwidth covering the desired frequency range. Here, we proposed new type of Frequency Selective Surface (FSS) with miniaturized resonator element to enhance the gain of an CPW antenna. Furthermore, the miniaturization of the Frequency Selective Surface unit cell is attained by coupling the two meandered wire resonators. The wire resonator is separated by thin and single substrate layer. The structure of the FSS is shown to have a FSS unit cell dimension that is miniaturized to 0.057λ. The CPW antenna size is only 28.8mm × 46.5mm operating at 2.45 GHz frequency. With the additional of the FSS, the antenna's gain reaches up from 1.8 dBi to 2.6 dBi with omnidirectional radiation pattern.
  • Publication
    Development of multiband fractal planar inverted F antenna (F-PIFA) for mobile applications
    In the past few years, demand in unification of wireless hardware has propelled new development of antenna. With the advances on antenna technology, it becomes attractive to enhance the capabilities of antenna in many areas such as mobile communication and wireless application. The requirements of ubiquitous antenna are small in size, simple, robust, have a shielding mechanism, multisystem and wide bandwidth. The reason is, currently, there are five bands that are assigned for world mobile services. Due to the aforementioned issues, a novel Fractal planar inverted F antenna (F-PIFA) based on the self affinity design is presented in this research. This research is conducted in order to develop an antenna with low cost, small in size, high performance, and capable to operate at multiple frequency bands. The F-PIFA development processes include specification definition, selection of the dielectric material and construction of prototype using CST software tools. In conducting this research, the production of prototypes is divided into three stages. The first stage is to develop three different iteration of F-PIFA and to evaluate its performance. The second stage is to fabricate, measure the antenna performance as well as the SAR value. Finally, the design is investigated and improved for future works. This research has successfully produced an antenna with good efficiency without degrading bandwidth and gain of the F-PIFA. The antenna has a total dimension of 27mm x 27mm is designed and optimized in order to receive GSM (Global System for Mobile Communication) and UMTS (Universal Mobile Telecommunication System) and HiperLAN (HigH Performance Radio LAN) with the frequency range from 850-960 MHz, 1900 MHz to 2100 MHz, 1885 to 2200 MHz for 3G and 4800 MHz to 5800 MHz for HiperLAN respectively. This omni-directional antenna invented here have 65-90% efficiency with peak gain value that is 3.57 dB, and be able to produce less than 2W/kg SAR value.
  • Publication
    Development of U-Shape Slot Wearable Antenna for In-Body Communications
    The ability to have a communication with devices implanted inside a human body will cause a great improvement in current wireless medical applications technology. Wireless Capsule Endoscopy (WCE) is a medical device that could send images from inside of human's intestines to the sensor outside the body. However, this device has few disadvantages like its location cannot be detected once it entered the body and it also cannot be control from outside the body. Considering these factors, an antenna that has the ability to penetrate into human body tissues for in-body communication is proposed. UWB system has considered as the solution for future in-body communication devices since current standard does not allow high data rate wireless connections between implanted nodes. Low part of UWB frequency band which is 3.1 GHz to 5.0 GHz is used in this research in order to reduce the attenuation through the body tissues as the frequency increase. The design of this antenna has taken in consideration of the propagation medium which is the human body tissues. Simulation for the designed antenna was done in CST Software. The size of this antenna is designed to be compact and wearable on human body. The substrate used for this antenna is cotton to ensure comfort once it is placed on the human body. The results that are considered in this research are the S11, directivity and gain of the antenna. Both simulation results and measured results are compared to evaluate the ability of this antenna.
  • Publication
    A Review of Antennas for Picosatellite Applications
    ( 2017)
    Abdul Halim Lokman
    ;
    Ping Jack Soh
    ;
    ;
    Herwansyah Lago
    ;
    Symon K. Podilchak
    ;
    Suramate Chalermwisutkul
    ;
    Mohd Faizal Jamlos
    ;
    ;
    Prayoot Akkaraekthalin
    ;
    Steven Gao
    Cube Satellite (CubeSat) technology is an attractive emerging alternative to conventional satellites in radio astronomy, earth observation, weather forecasting, space research, and communications. Its size, however, poses a more challenging restriction on the circuitry and components as they are expected to be closely spaced and very power efficient. One of the main components that will require careful design for CubeSats is their antennas, as they are needed to be lightweight, small in size, and compact or deployable for larger antennas. This paper presents a review of antennas suitable for picosatellite applications. An overview of the applications of picosatellites will first be explained, prior to a discussion on their antenna requirements. Material and antenna topologies which have been used will be subsequently discussed prior to the presentation of several deployable configurations. Finally, a perspective and future research work on CubeSat antennas will be discussed in the conclusion.
  • Publication
    Application of FSS for Microstrip Antenna for Gain Enhancement
    In this present paper, a dual-band microstrip patch antenna (MPA) using frequency selective surface (FSS) is proposed. The dual-band MPA is designed using the rectangular shaped patch with an elliptical slot at the center of the patch and full ground plane. The FSS in this paper act as a reflection plane which is loaded onto the dual-band MPA in order to improve the gain of the antenna at higher band. The FSS is obtained by the periodic array of 3 5-unit cell in the x-y direction, which based on the amalgamation of a square and circular loop elements. After merging the FSS, the gain and return loss at 5 GHz increased to 0.915 dB and -25.08 dB respectively. The dual-band MPA is simulated using the FR-4 substrate with a thickness of 1.6 mm and a relative permittivity of 4.4. The overall size of the MPA and FSS is relatively compact and easy to fabricate. The proposed antenna can be used in WiMAX and WLAN applications.
  • Publication
    UHF RFID tag antennas for wearable devices
    (AIP Publishing Ltd., 2023) ;
    Wan Nur Azreen Azemin
    ;
    Nornikman Hassan
    ;
    ;
    RFID technology is evolving as one of the most popular technologies in this era of technology, fast gaining attention due to high demand from users and rapidly garnering interest in scientific and commercial areas. The frequency used will be determined by the RFID application, and the power rate will change as the frequency increases. Without a straight line of sight, the RFID tag antenna can identify distinct objects. For wearable applications, several RFID tag antennas are too big to match the chip impedance. In order to overcome that problem, a small tag RFID tag antenna for UHF is designed which aimed to be operated from 865 to 867 MHz for assembling production. Impedance matching is used to transforms the impedance of the radiating antenna, to match the chip impedance. To design and simulate the designed antenna, CST Microwave Studio software has been used in this project to get the desired result which is the return loss and gain. The design for this antenna is very simple to ease the fabrication process. Overall, the construction comprises a spiral-shaped loop RFID tag antenna printed on Roger substrate RO4350 with a height of 0.8 mm and a dielectric constant of 3.3. The simulation result of the reflection coefficient of the antenna is 866 MHz at the operating frequency.
  • Publication
    Mini double ridge horn antenna for free space measurement
    (AIP Publishing Ltd., 2023)
    Renukka Sivakumar
    ;
    Lee Yeng Seng
    ;
    ;
    Ping Jack Soh
    This paper presents the design of a double ridge horn antenna (DRHA) with an operating frequency of 2.4 GHz to 9.8 GHz for free space measurement. The DRHA is designed using CST Studio Suite. The DRHA is built with metallic grid sidewalls, ridges, the shield of coax, cavity back, and bell section. Furthermore, the DRHA exhibits improved radiation patterns with a maximum E-plane beamwidth of 102 degrees and H-plane beamwidth of 92 degrees, and maximum gain up to 16.3 dBi. The simulated results were analyzed and discussed in this paper. This double ridge horn antenna exhibits improved radiation patterns and gains. This shows that the double ridge horn antenna can fulfill the higher demands in antenna applications and in free space material measurement. The antenna presents desirable results throughout the operating frequency. © 2023 American Institute of Physics Inc.. All rights reserved.
  • Publication
    Localization of person under surveillance using GPS mobile apps
    (AIP Publishing Ltd., 2023) ;
    Nur Hafizah Iffah Azhar
    ;
    ;
    Massila Kamalrudin
    ;
    Relatively more smartphones developed nowadays come with GPS location software. GPS information is fetched from the satellites and can be retrieved from Bluetooth, wi-fi, cell-id, and a combination of those tools. GPS-based mobile apps have the features of fetching the location of a device using geo-coordinates and some measurement which is an added value in developing various software. Due to the pandemic disease of Covid-19, the world is now aiming for global digitalization. Countries such as Singapore, Chine, and even Malaysia developed applications that can help the citizen in obeying the SOP and receiving current and reliable information regarding the Covid-19 issue. Thus, a real-time monitoring application for PUS s beneficial to break the chain and contain the disease. This research has been done to develop a localization application for Person Under Surveillance using GPS mobile apps. The application implemented the Firebase Authentication in the sign-up and sign-in process and is developed using Android Studio IDE 4.1 integrated with cloud-hosted database Firebase Realtime Database. Android version 6.0 is used which is API level 23. Application is developed to have the functionalities of user registration, fetching coordinates, setting a boundary, and in-app alert. The application was installed and tested on the Pixel 3 API 23 emulator.
  • Publication
    ABCS antenna for wireless body area network at 26 GHz
    (AIP Publishing Ltd., 2023)
    Muhammad Afifi
    ;
    ; ;
    Soh Ping Jack
    The paper presents the design and investigation of a wearable textile antenna (receiver) and transmitter antenna operating in the wireless body area network (WBAN) of 26 GHz band for 5G mobile networks. The wearable antenna with an overall size of 30 mm x 40 mm x 1.26 mm achieves good impedance matching, high gain, and directive radiation pattern. Both antennas were designed using CST Microwave Studio to validate the simulation results. A rectangular radiating patch comprises a Shieldit electrotextile situated on one side of a non-conductive substrate panel with the ground plane. The bed sheet cotton fabric is used as the non-conductive substrate due to its widespread use in daily clothing with a dielectric constant is 3.2 and the loss tangent is 0.0027. In addition, the wearable antenna successfully achieved the high gain and efficiency of 12 dB and 90.83% respectively. Moreover, the antenna operating at 26 GHz with -40.48 dB return loss, which is less than the -10 dB in requirement. The simulated results show that this proposed wearable antenna is best suited for wireless body area network applications. Hence, the wearable antenna is simple, compact and easy to fabricate.