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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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.

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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.

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