Che Muhammad Nor Che Isa
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Preferred name
Che Muhammad Nor Che Isa
Official Name
Che Muhammad Nor, Che Isa
Alternative Name
Che Isa, Che Muhammad Nor
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Scopus Author ID
57210792893

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Performance enhancement of semicircular shaped array antenna using metasurface

2020 , H. Lago , M. Faizal Jamlos , A. Narbudowicz , Soh Ping Jack , A. R. Haron , Che Muhammad Nor Che Isa , M. H. Limbah

This work studies the integration of a semicircular shaped array antenna into an Artificial Magnetic Conductor (AMC) which resonate at the desired operating frequency of 9.41 GHz. The proposed AMC performs as a high impedance surface with a high permeability (approximately 7.08) at 9.41 GHz, with a perfect magnetic conductor characteristic. As result, the AMC is able to be stacked adjacent to the semicircular shaped. The simulation results show that the AMC has successfully enhanced the gain and efficiency of the antenna to 9.55 dB and 97% respectively compared to 8.44 dB and 96% without AMC. Besides that, a slight bandwidth improvement, from 395 MHz to 398 MHz can be observed with the AMC. Both simulated and measured results show a good agreement in term of reflection coefficients and radiation patterns.

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A triband wearable antenna for location tracking using cospas-sarsat and GNSS

2025 , Rais Ahmad Sheikh , Azremi Abdullah Al-Hadi , Roy B. V. B. Simorangkir , Thennarasan Sabapathy , Rizwan Khan , Prayoot Akkaraekthalin , Surentiran Padmanathan , Toufiq Md Hossain , Che Muhammad Nor Che Isa , Ping Jack Soh

This paper presents the design of a tri-band antenna operating in the Cospas-Sarsat (C-S) and GPS/GNSS bands applicable for the Internet of Things (IoT). Implemented with flexible and robust materials, the antenna operates in three distinct frequencies: 406 MHz for C-S applications and 1227 MHz (L2) and 1575 MHz (L1) for GPS/GNSS applications. The measured 10-dB impedance bandwidth is from 1.517-1.587 MHz (in L1 band) and from 1.192-1.232 MHz (in L2 band). In C-S band, the measured 6-dB bandwidth is from 393 to 406.5 MHz. The 3 dB axial ratio (AR) bandwidth in the L1 and L2 bands are 17 MHz (1.08%) and 18 MHz (1.47%), respectively. The antenna demonstrates a measured gain of 1.61 dB at 406 MHz, exceeding the simulated gain of 0.573 dB, and features a beamwidth of 140°. The measured gains for the L2 and L1 bands closely align with the simulations, although a slight reduction in gain is observed for the L2 band. In the H-plane, zenith-directed main lobes produce measured gains of 1.61 dB for 406 MHz, 2.71 dB for L2, and 3.51 dB for L1. On the other hand, the measured efficiency for the antenna is 36.32% (in the C-S band), 54% (in L1 band) and 60.12% (in L2 band). Both measured and simulated results consistently showed good agreements in terms of gain, polarization, and efficiency. Moreover, the antenna design incorporates effective shielding against electromagnetic radiation, conforming to specific absorption rate (SAR) values of 0.046, 0.077, and 0.035 W/Kg in C-S, L1 and L2 bands respectively. Antenna integration into the life vest foam prior to placement on the human chest significantly influenced axial ratio variations. In the L1 band, the AR increased from 0.43 dB to 3.34 dB, while in the L2 band, it rose from 0.56 dB to 8.66 dB. This indicates a more pronounced effect on polarization characteristics at the lower frequency. Overall, the proposed tri-band antenna presents promising capabilities for location tracking applications, with potential for integration into wearable devices for enhanced safety and tracking functionalities.

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Feasibility study on embroidered Wi-Fi antenna performances

2021 , Che Muhammad Nor Che Isa , Muhammad Syukri Jaafar , Zahari Awang Ahmad , Amir Nazren Abdul Rahim

Performance of a dual-band coplanar patch antenna with bending and wet condition is described in this paper. The antenna structure is made from common clothing fabrics and operates at the 2.45 and 5 GHz wireless bands. The antenna's radiating element is using Nora Dell serves as a ground plane and Felt as the substrate. The final part carries out the simulation on forward, backward bending, and also the wet condition in CST software. The comparison of two bending conditions is discussed in this report.

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An ultrawideband full flexible 4 elements DGS based MIMO antenna for Sub-6 GHz wearable applications

2024-03 , Bikash Chandra Sahoo , Azremi Abdullah Al-Hadi , Saidatul Norlyana Azemi , Surentiran Padmanathan , Sadia Afroz , Wee Fwen Hoon , Soh Ping Jack , Che Muhammad Nor Che Isa , Soumya Ranjan Mishra

In this article, a compact wearable quad element MIMO antenna is presented operating at 4.5 GHz for 5G n77, n78, and n79 bands with the use of polyester substrate with a size of 80 × 82 × 0.4 mm3. Here T-shaped defected ground structure (DGS) technique has been utilized to improve the impedance bandwidth along with the reduction of the mutual coupling between the radiating elements. The antenna is evaluated in terms of reflection coefficient, gain, efficiency, and radiation pattern. The proposed MIMO antenna attained a maximum simulated gain of 4.3 dBi, and an efficiency of 96 % in the resonating band.

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A 3.5 GHz wearable antipodal vivaldi antenna for 5G applications

2024-01 , Sadia Afroz , Azremi Abdullah Al-Hadi , Surentiran Padmanathan , Saidatul Norlyana Azemi , Wee Fwen Hoon , Bikash Chandra Sahoo , Yen San Loh , Che Muhammad Nor Che Isa , Lun Hao Tung , Lai Ming Lim , Zambri Samsudin , Idris Mansor , Soh Ping Jack

This paper represents a wideband wearable antenna for 5G applications. In this proposed design, an antipodal vivaldi antenna structure is implemented on a polyimide and polyester combined substrate. The 120 × 95 × 0.82 mm3 sized antenna acquired a wide bandwidth of 910 MHz with a realized gain of 5.42 dBi and efficiency of 96 percent.

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Comparison Study of UHF Sensor Modelling Based on 4th Order Hilbert Fractal Category for Partial Discharge Detection in Power Transformer

2020-12-11 , Roslizan Nur Dayini , Mohamad Nur Khairul Hafizi Rohani , Afifah Shuhada Rosmi , Baharuddin Ismail , Mohd Aminudin Jamlos , Wooi Chin Leong , Jalil M.A.A. , Che Muhammad Nor Che Isa

PD detection is an effective method of inspecting insulation defects and identifying potential faults in a power transformer. Electromagnetic waves generated due to PD can be detected by ultrahigh-frequency (UHF) sensor in the frequency band greater than 300 MHz. However, the size and the frequency bandwidth of a UHF sensor for PD detection are the concern for practical installation inside a transformer. High sensitivity and wide bandwidth of sensors are needed in order to detect the PD signal at an early stage. This paper presents an array with partial ground 4th order Hilbert fractal UHF sensor for PD detection inside a power transformer. This UHF sensor was modeled to capture PD signal in a range of frequencies between 300 MHz to 3 GHz. The sensor is designed by using CST software where the transmission lines combined 2 sensors become 1 output by setting the dimension of 100 x 200 mm for length and width with an FR4 epoxy substrate of thickness 1.6 mm. Based on the simulation result, the proposed sensor is obtained a PD signal measurement with a reflection coefficient below-10 dB with VSWR ?5. The advantages of this sensor have a wide bandwidth, high sensitivity and suitable size for easy installation. Thus, this sensor has been qualified as UHF PD detection in the power transformer.

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The design evolution of trio-band vivaldi antenna with meander-line-fed shape for ground penetrating radar application

2024-01 , Mohd Syahir Ahmad Azhari , Saidatul Norlyana Azemi , Mimi Diana Ghazali , Che Muhammad Nor Che Isa , Ainur Fasihah Mohd Fazilah

This paper is proposed based on considerable reviewed design techniques. It works at 200MHz, 800MHz and 1,200MHz named as “Trio-Band” with the fixed size of 300mm×300mm×1.6mm of the FR4 substrate. The antenna application is for Ground Penetrating Radar (GPR) with targeted depth range is from 10cm to 1,000cm. The combination of slotted shapes which is Half-circle, Staircase, Quarter-eclipse and Circular-Ring are applied to achieve the Trio-Band with the parametric analysis to determine the appropriate size. The final Vivaldi antenna achieves the reflective coefficient (S11) with -30.05dB (200MHz), -12.05dB (800MHz) and -15.35dB (1,200MHz) as well as 50Ω of impedance matching.

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Compact full flexible vivaldi antenna for 3.5 GHz wearable applications

2023 , Bikash Chandra Sahoo , Azremi Abdullah Al-Hadi , Saidatul Norlyana Azemi , Wee Fwen Hoon , Surentiran Padmanathan , Sadia Afroz , Che Muhammad Nor Che Isa , Yen San Loh , Muhammad Syahir Mahyuddin , Lai Ming Lim , Zambri Samsudin , Idris Mansor , Soh Ping Jack

In this paper, a compact wearable Vivaldi antenna resonating at 3.5 GHz is proposed for 5G n77, and n78 bands. It is designed upon a flexible polyester substrate having dielectric constant (εr) of 1.34 and loss tangent (tan δ) of 0.005. The antenna parameters were optimized via parametric analyses using CST software with a size of 45 × 45 × 0.4 mm3 (length × width × height). The antenna is evaluated in terms of reflection coefficient, gain, efficiency, radiation pattern, and surface current density. This antenna attained a maximum simulated gain of 4.7 dBi, and an efficiency of 98 % in the resonating band.

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