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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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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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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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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.