Norfatihah Bahari
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Norfatihah Bahari
Official Name
Norfatihah, Bahari
Alternative Name
Bahari, N.
Bahari, Norfatihah
Bahari, N. I.
Main Affiliation
Scopus Author ID
56610151300
Researcher ID
CCZ-6056-2022

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Now showing 1 - 10 of 14
  • Publication
    Comparison of RFID Tag structure for wearable applications system
    (Semarak Ilmu Publishing, 2025-04)
    Nur Hidayah Ramli
    ;
    Rashidah Che Yob
    ;
    Liyana Zahid
    ;
    Norfatihah Bahari
    This paper proposed a comparison of Radio- Frequency Identification (RFID) tags for wearable applications. Three types of proposed RFID tag structures are designed which are square, hexagonal, and octagonal shapes to operate at frequencies 1.0GHz to 12GHz. The RFID tag structure consists of several meander line radiators. The structure of the meandered line radiator is attached to the cotton and jeans fabric. A monostatic radar system which consists of a Vector Network Analyzer and a horn antenna is configured to test the RFID tag in real life. The performances of RFID tags are evaluated in terms of the reflection coefficient (S11) and their operating frequency. The results will be guidelines while designing RFID tag structures for wearable application systems in the future.
  • Publication
    IoT based earthquake detection system
    (Semarak Ilmu Publishing, 2025-09)
    Norfatihah Bahari
    ;
    Nor Irfan Multazam Nor Azmi
    ;
    Herwansyah Lago
    ;
    Mohd Wafi Nasrudin
    ;
    Rashidah Che Yob
    ;
    Nur Hidayah Ramli
    This paper proposes an IoT based Earthquake Detection System for the early warning and quick detection of the earthquake. Earthquakes are one of the rare natural disasters in Malaysia but when the earthquake happened, it could damage infrastructure and cause deaths. This system is aimed to monitor the earthquake levels and warn people about earthquake dangers. To detect the vibration on the ground surface, an accelerometer has been connected to the microcontroller Arduino Uno R3. Then NRF24L01 transceiver module has been used to connect between the transmitter and receiver part. In order to receive the notifications about the earthquake, the ESP8266 Wi-Fi module is linked to the Blynk App. This proposed system is very user-friendly and economical, making it favourable to be used in the earthquake zones.
  • Publication
    Shape Recognition of GPR Images using Hough Transform and PCA plus LDA
    ( 2022-01-01)
    Hasimah Ali
    ;
    Norfatihah Bahari
    ;
    Mohamed Elshaikh Elobaid Said Ahmed
    ;
    Siti Nurul Aqmariah Mohd Kanafiah
    ;
    Amran T.S.T.
    ;
    Jusman Y.
    Ground penetrating radar (GPR) is a nondestructive test used for shallow subsurface investigation such as land mine detection, mapping and locating buried utilities. In practical applications, GPR images could be noisy due to system noise, the heterogeneity of the medium, and mutual wave interactions. Hence, it is a complex task to recognize the hyperbolic pattern from GPR B-scan images. Thus, this project proposes combined shape recognition of buried objects using Hough Transform (HT) and PCA plus LDA in GPR images. The use of HT is justified because it has the property of transforming global curve detection into efficient peak detection in the Hough parameter space. Whereas PCA plus LDA tries to maximize between-class scatter while minimizing within-class scatter. In this framework, the preprocessed GPR images were extracted using HT. The extracted HT features were subjected to PCA plus LDA to map them from high into lower dimensional features. Then, the reduced PCA+LDA features were used as input to the k-NN classifier to recognize four geometrical shapes cubic, disc, and spherical of the buried objects. Based on the results obtained, the average recognition rate of reduced HT features using PCA plus LDA was achieved 85.30% thus shows a promising result.
      1
  • Publication
    A triangular MIMO array antenna with a double negative metamaterial superstrate to enhance bandwidth and gain
    ( 2020-08-01)
    Ojo R.
    ;
    Jamlos M.F.
    ;
    Soh Ping Jack
    ;
    Mohd Aminudin Jamlos
    ;
    Norfatihah Bahari
    ;
    Lee Y.S.
    ;
    Al-Bawri S.S.
    ;
    Abdul Karim M.S.
    ;
    Khairi K.A.
    Multiple-input-multiple-output (MIMO) array antenna integrated with the double negative metamaterial superstrate is presented. The triangular metamaterial unit cell is designed by combining two triangular elements positioned in complementary on the same plane at different sizes. Such design with more gaps is used to excite rooms for more capacitance effects to shift the resonance frequency thus enlarging the bandwidth of the MIMO antenna. The unit cell is arranged in 7 × 7 periodic array created a superstrate metamaterial plane where the Cstray exists in parallel between the two consecutive cells. It is found that the existence of Cstray and gaps for each unit cells significantly influenced the bandwidth of the MIMO antenna. The higher value of the capacitance will lead to the negativity of permittivity. The superstrate plane is then located on top of the 4 × 2 MIMO with a gap of 5 mm. The integration resulted in improving the bandwidth to 12.45% (5.65-6.4GHz) compared to only 3.49% bandwidth (5.91-6.12GHz) of the MIMO antenna itself. Moreover, the negative permeability characteristic is created by a strong magnetic field between the complementary unit cells to have 14.05-dBi peak gain. Besides that, the proposed antenna managed to minimize the mutual coupling and improve the mean effective gain, envelope correlation coefficient, and multiplexing efficiency.
      2  26
  • Publication
    An Impedance Matching Network towards Amplifier Design from Conceptual to Practical: Simulation Study
    ( 2021-07-26)
    Yob R.C.
    ;
    Ramli N.H.
    ;
    Norfatihah Bahari
    ;
    Zahid L.
    ;
    Nasrudin M.W.
    In many systems, the impedance matching networks are vital to ensure their having good performances, especially in such systems performances that related to the gain, linearity, and quality factors. This article mainly focuses on the simulation study of the impedance matching network from conceptual to practical on amplifier design. This simulation study from the conceptual of the ideal transmission-line based design to the practical of the microstrip-line based circuit implemented by using LineCalc of the ADS tool. The gallium nitride high electron mobility (GaN-HEMT) transistor by Cree is being one of the key components in understanding the importance of the impedance matching networks on the amplifier design a t the operating frequency of 5 GHz. The Agilent's Advance Design Systems (ADS) is used to perform this research. The obtained voltage standing wave ratio (VSWR) are approximately to 1 for both conceptual and practical of the impedance matching towards the amplifier design a t5 GHz. Thus, it is showing the maximum power transfer was occurring from the power stages to the load.
      1  18
  • Publication
    Compact bidirectional circularly polarized dedicated short range communication antenna for on-board unit vehicle-to-everything applications
    ( 2020-05-01)
    Rahman N.A.A.
    ;
    Mohd Aminudin Jamlos
    ;
    Jamlos M.F.
    ;
    Soh Ping Jack
    ;
    Norfatihah Bahari
    ;
    Hossain T.M.
    This article presents a newly circularly polarized (CP) antenna for V2X's dedicated short range communications applications. Its CP characteristic is enabled by a 70 Ω sequential phase feeding network and sequential rotation technique designed on top of the substrate. It has features of ≈90° phase difference in sequence between ports of S21 = 2.4°, S31 = −87°, S41 = −180°, and S51 = −276°, resulting in a 2.19 dB axial ratio centered at 5.9 GHz. The length of the SP feeding network to each ports designed in the different form of meander lines are the key to control the generated phase at the center frequency It also contributes to the smaller final size of 0.59λ × 0.59λ. The proposed antenna operated from 5.850 to 5.925 GHz with a gain between 4 and 6 dBi. The gains are radiated in bidirectional mode due to the presence of the complimentary dipoles located on the opposite side of the substrate. These features indicate the suitability of the proposed antenna in compliance to the ITS-G5 OBU V2X standard.
      1  26
  • Publication
    Compact Parallel Coupled Line Microstrip BPF Design for 5G Applications
    ( 2023-01-01)
    Anak Temuli H.U.
    ;
    Khairul Najmy Abdul Rani
    ;
    Fairul Afzal Ahmad Fuad
    ;
    Khairil Syahmi Musa
    ;
    Norfatihah Bahari
    ;
    Faizah Abu Bakar
    ;
    Mohd Aminudin Jamlos
    ;
    Rahayu Y.
    A compact parallel coupled line microstrip bandpass filter (BPF) for sub-6 GHz fifth generation (5G) applications is designed operating between edge frequencies of 3.40 and 3.80 GHz. The design is designed and simulated by means of the Advanced Design System (ADS) software using the flame retardant-4 (FR-4) board as the substrate. The BPF design applies the insertion loss method (ILM) to generate a parallel coupled line filter structure that performs passband permission and unwanted noise attenuation below 3.40 GHz and above 3.80 GHz, respectively. Consistent and relevant performances in terms of matching impedance, return loss (S11), insertion loss (S21), voltage standing wave ratio (VSWR), far field radiation pattern, gain, directivity, and radiated efficiency promise the microstrip BPF design has a potential for sub-6 GHz 5G applications.
      2  38
  • Publication
    A switchless pentagon-shaped reconfigurable antenna for radar applications
    (IOP Publishing, 2020)
    Norfatihah Bahari
    ;
    Rashidah Che Yob
    ;
    Liyana Zahid
    This paper proposes a switchless pentagon-shaped microstrip patch antenna for radar and radionavigation applications. The antenna is built on Rogers RT5880 substrate with five rectangular radiating elements on top. Five ports have been set up to operate at 13.5 GHz resonant frequency. Besides having reflection coefficient below -10 dB, the antenna also offers high gain when about 8.29 dB is achieved. The proposed antenna also has a bi-directional radiation pattern with 360° of beam steering.
      3  24
  • Publication
    Artificial Magnetic Conductor to Enhance Microstrip Patch Textile Antenna Performance for WiMAX Application
    ( 2020-12-18)
    Liyana Zahid
    ;
    Hanif Suhairi Abu Bakar
    ;
    Khairul Najmy Abdul Rani
    ;
    Thennarasan Sabapathy
    ;
    Mohd Aminudin Jamlos
    ;
    Mohamad Rizal Abdul Rejab
    ;
    Khairil Syahmi Musa
    ;
    Hamzah D.
    ;
    Rashidah Che Yob
    ;
    Norfatihah Bahari
    A rectangular microstrip patch textile antenna with Artificial Magnetic Conductor (AMC) operated at the center frequency of 5.80 gigahertz (GHz) for Worldwide Interoperability for Microwave Access (WiMAX) application was designed and simulated using the CST Microwave Studio 2016 and fabricated in this study. The use of AMC could solve the inflexibility of FR4 substrate that limits human body movement and reduce the radiation scattered on the human body whilst increasing the antenna gain and directivity. The antenna consists of 5 5 square shape gap of AMC unit cells ground layer using ShieldIt Super, five substrate layers using cotton (viscose) fabric as well as patch layer and another ground layer using the same ShieldIt Super. AMC is a metamaterial that imitates the conduct of zero reflection phase of Perfect Magnetic Conductor (PMC) on the resonant frequency not evidently existed in nature. Overall, the antenna with AMC has the significant return loss, S11 below than -30 decibel (dB), gain improved to more than 8 dB, and directivity elevated to more than 9 dBi at resonant frequency near to 5.80 GHz, respectively.
      10  32
  • Publication
    Cylindrical Dielectric Resonator as Dielectric Matching on Microwave Amplifier for the Unconditionally Stable and Conditionally Stable Transistor at 5 GHz Frequency
    ( 2022-12-01)
    Rashidah Che Yob
    ;
    Mahyuddin N.M.
    ;
    Ain M.F.
    ;
    Mohd Aminudin Jamlos
    ;
    Nur Hidayah Ramli
    ;
    Norfatihah Bahari
    ;
    Mohd Wafi Nasrudin
    ;
    Liyana Zahid
    Stability and matching techniques on microwave amplifier have been an important consideration to maintain their required performances, but typically its frequency dependent. Thus, a frequency variable mechanism is required. The dielectric matching employing the stability and matching techniques on microwave amplifier with cylindrical dielectric resonator has been investigated and realized. The cylindrical dielectric resonator (CDR) with parallel microstrip lines is proposed at 5 GHz frequency for unconditionally stable and conditionally stable transistor as dielectric matching. Hence, the proposed dielectric resonator with +2 mm spacing and 155Ëš of curved configuration indicated the best performances for preliminary study. The result improves the performance of the parallel inhomogeneous CDR by 9.77%. Subsequently, the homogeneous CDR is also successfully working as the variable frequency mechanism for unconditionally stable and conditionally stable transistor at 5 GHz frequency in maintaining their stability performances.
      36  1