Thennarasan Sabapathy
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Thennarasan Sabapathy
Official Name
Thennarasan, Sabapathy
Alternative Name
Sabapathy, Thennarasan
Sabapathy, Thenna
Sabapathy, T.
Sapabathy, T.
Main Affiliation
Scopus Author ID
35424377200
Researcher ID
AAA-9706-2019

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Negative Index Metamaterial-Based Frequency-Reconfigurable Textile CPW Antenna for Microwave Imaging of Breast Cancer

2022-02-01 , Hossain K. , Thennarasan Sabapathy , Muzammil Jusoh , Lee S.H. , Rahman K.S.A. , Kamarudin M.R.

In this paper, we report the design and development of a metamaterial (MTM)-based directional coplanar waveguide (CPW)-fed reconfigurable textile antenna using radiofrequency (RF) varactor diodes for microwave breast imaging. Both simulation and measurement results of the proposed MTM-based CPW-fed reconfigurable textile antenna revealed a continuous frequency re-configuration to a distinct frequency band between 2.42 GHz and 3.2 GHz with a frequency ratio of 2.33:1, and with a static bandwidth at 4–15 GHz. The results also indicated that directional radiation pattern could be produced at the frequency reconfigurable region and the antenna had a peak gain of 7.56 dBi with an average efficiency of more than 67%. The MTM-based reconfigurable antenna was also tested under the deformed condition and analysed in the vicinity of the breast phantom. This microwave imaging system was used to perform simulation and measurement experiments on a custom-fabricated realistic breast phantom with heterogeneous tissue composition with image reconstruction using delay-and-sum (DAS) and delay-multiply-and-sum (DMAS) algorithms. Given that the MWI system was capable of detecting a cancer as small as 10 mm in the breast phan-tom, we propose that this technique may be used clinically for the detection of breast cancer.

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A multilayered acoustic signal generator for low power energy harvesting

2017-10-10 , Awal M.R. , Muzammil Jusoh , Hasliza A Rahim @ Samsuddin , Thennarasan Sabapathy , Mohamed Nasrun Osman , Mohd Ilman Jais , Kamarudin M.R.

This paper presents the design and analysis of a multilayer cantilever to harvest vibration energy by generating acoustic signal. To do so, a five layer configuration is used to design the cantilever. Lead Zirconate Titanate (PZT-8), Stainless Steel 405 Annealed, Aluminum and Zinc Oxide are used to develop the layers. Water is used as the medium to analyze the sound propagation pattern. Sound Pressure Level, displacements and electric potential of the cantilever are analyzed along with other parameters. From the results, it is evident that, the proposed cantilever can propagate sound within a range of 78.7 dB to 73.4 dB in a 50 mm spherical distance.

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Investigation on the Effect of Deflected Ground Structure in Multi-Direction Steerable Antenna for WSN

2020-03-20 , Zainudin N.A.F.M. , Osman M.N. , Thennarasan Sabapathy , Muzammil Jusoh

In this paper, a multi-direction steerable radiation pattern antenna is designed and investigated, which operates at 2.45 GHz frequency. The radiation pattern reconfigurable is achieved by locating four parasitic elements surrounding the driving element at the centre. The artificial switches, are currently used to replace the ideal diode for proof of the concept, are inserted at the specific position on the parasitic element. By controlling the state ON/OFF of the switches, the parasitic is grounded via shorting pin, thus realizing the beam steering to be directed into four direction angles; right, left, upwards and downwards. In this research, an investigation on the effect of deflected ground plane on the steering angles has been carried out. With minimum numbers of switches deployed, the proposed antenna is a potential candidate to serve as a transmitting element in WSN applications.

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A Patternless Piezoelectric Energy Harvester for Ultra Low Frequency Applications

2020-01-01 , Awal M.R. , Jusoh M. , Thennarasan Sabapathy , R Badlishah Ahmad , Kamarudin M.R. , Osman M.N. , Ahmad M.F. , Rahman S.A. , Dagang A.N.

This paper presents a pattern less piezoelectric harvester for ultra low power energy applications. Usually patterned cantilevers are used as vibration energy harvester which results additional fabrication process. Hence, to reduce the process, a four layer cantilever configuration is used to design the harvester with Aluminum, Silicon and Zinc Oxide. The device dimension is settled to 12×10×≈0.5009 mm3 with ≈300 nm deposition thickness for each layer. The modeling and fabrication processes are demonstrated in detail. The induced voltage by the cantilever is obtained through the analytical and practical measurements. From the measurements, it is found that, the maximum induced voltage is 91.2 mV from practical measurement with voltage density of 1.517 mV/mm3. It is evident from the results that, this pattern less model can be useful for next generation vibration energy harvester with simpler technology.

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ENG and NZRI Characteristics of Decagonal-Shaped Metamaterial for Wearable Applications

2020-08-01 , Hossain K. , Thennarasan Sabapathy , Muzammil Jusoh , Soh Ping Jack , Fazilah A.F.M. , Halim A.A.A. , Raghava N.S. , Podilchak S.K. , Schreurs D. , Abbasi Q.H.

A decagonal-shaped split ring resonator metamaterial based on a wearable or textile-based material is presented in this work. Analysis and comparison of various structure sizes are compared considering a compact 6\times 6\ \mathrm{m}\mathrm{m}{2} metamaterial unit cell, in particular, where robust transmission-reflection (RTR) and Nicolson-Ross-Weir (NRW) methods have been performed to extract the effective metamaterial parameters. An investigation based on the RTR method indicated an average bandwidth of 1.39 GHz with a near-zero refractive index (NZRI) and a 2.35 GHz bandwidth when considering epsilon negative (ENG) characteristics. On the other hand, for the NRW method, approximately 0.95 GHz of NZRI bandwidth and 2.46 GHz of ENG bandwidth have been observed, respectively. These results are also within the ultra-wideband (UWB) frequency range, suggesting that the proposed unit cell structure is suitable for textile UWB antennas, biomedical sensors, related wearable systems, and other wireless body area network communication systems.

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Multi-stage feature selection (MSFS) algorithm for UWB-based early breast cancer size prediction

2020-08-01 , Vijayasarveswari V. , Allan Melvin Andrew , Muzammil Jusoh , Thennarasan Sabapathy , Rafikha Aliana A Raof , Mohd Najib Mohd Yasin , R Badlishah Ahmad , Khatun S. , Hasliza A Rahim @ Samsuddin

Breast cancer is the most common cancer among women and it is one of the main causes of death for women worldwide. To attain an optimum medical treatment for breast cancer, an early breast cancer detection is crucial. This paper proposes a multistage feature selection method that extracts statistically significant features for breast cancer size detection using proposed data normalization techniques. Ultra-wideband (UWB) signals, controlled using microcontroller are transmitted via an antenna from one end of the breast phantom and are received on the other end. These ultra-wideband analogue signals are represented in both time and frequency domain. The preprocessed digital data is passed to the proposed multistage feature selection algorithm. This algorithm has four selection stages. It comprises of data normalization methods, feature extraction, data dimensional reduction and feature fusion. The output data is fused together to form the proposed datasets, namely, 8-HybridFeature, 9-HybridFeature and 10-HybridFeature datasets. The classification performance of these datasets is tested using the Support Vector Machine, Probabilistic Neural Network and Naïve Bayes classifiers for breast cancer size classification. The research findings indicate that the 8-HybridFeature dataset performs better in comparison to the other two datasets. For the 8-HybridFeature dataset, the Naïve Bayes classifier (91.98%) outperformed the Support Vector Machine (90.44%) and Probabilistic Neural Network (80.05%) classifiers in terms of classification accuracy. The finalized method is tested and visualized in the MATLAB based 2D and 3D environment.

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A Compact Wideband CSRR near Zero Refractive Index and Epsilon Negative Metamaterial for Wearable Microwave Applications

2021-07-26 , Hossain K. , Thennarasan Sabapathy , Muzammil Jusoh , Soh Ping Jack , Osman M.N. , Al-Bawri S.S.

A complementary split-ring resonator (CSRR) decagonal shaped textile-based single-negative metamaterial (MTM), considering a frequency range from 1 to 15 GHz, is presented in this paper. Seven different unit cell arrays (i.e., 1 1, 1 2, 1 3, 2 1, 2 2, 1 3 and 3 3) are analysed to evaluate the effects of the unit-cell arrays on the resonance frequencies of the MTM. The designed unit cell arrays exhibit average negative permittivity bandwidth of 12.87 GHz (from 1 to 12.87 GHz) and an average near-zero-refractive-index (NZRI) bandwidth of 11.98 GHz (from 1.015 to 12.995 GHz). Simultaneous negative permittivity and NZRI results at L, S, C, X and Ku frequency bands indicate the proposed MTM is suitable for various wearable applications in these frequency regimes.

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Analysis of Symmetric Two and Four-coil Magnetic Resonant Coupling Wireless Power Transfer

2022-04-01 , Ali A. , Mohd Najib Mohd Yasin , Rambe A.H. , Ismahayati Adam , Ramli N. , Hasliza A Rahim @ Samsuddin , Thennarasan Sabapathy , Mohd Natashah Norizan , Sobri S.A.

This study examined the efficiency of power transfer for two-coil and four-coil spiral magnetic resonant coupling wireless power transfer (WPT) using distance to coil diameter (D/dm) ratio and reflection coefficient, S21 value. Adding resonators reduced the total resistance in the two-coil WPT system while increasing the S21 values of the whole system. A same-size spiral coil was proposed for the system and simulated using computer simulation technology (CST). A prototype with similar specifications for a four-coil design was implemented for verification. The proposed method yielded an optimal efficiency of 76.3% in the four-coil system, while the two-coil WPT yielded a 23.2% efficiency with a 1.33 D/dm ratio.

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Low-Profile and Wider-Angle Beam Tilting Parasitic Array Resonator Antenna with Optimized Deflected Ground Plane on FR-4 Substrate

2023-04-01 , Mohd Zainudin N.A.F. , Mohamed Nasrun Osman , Thennarasan Sabapathy , Muzammil Jusoh , Mohd Najib Mohd Yasin , Mohamad M.K.

A low-profile and wide-angle radiation pattern reconfigurable antenna is designed, analyzed, and fabricated for wireless sensor network (WSN) applications, which operate at a 2.5-GHz frequency. This work aims to minimize the number of switches and optimize the parasitic size and ground plane to achieve a steering angle of more than 30° using a low cost-high loss FR-4 substrate. The radiation pattern reconfigurability is achieved by introducing four parasitic elements surrounding a driven element. In this work, the single driven element is fed by a coaxial feed, while other parasitic elements are integrated with the RF switches on the FR-4 as the substrate with dimensions of 150 × 100 mm (1.67 × 2.5 λo). The RF switches of the parasitic elements are surface mounted on the substrate. By truncating and modifying the ground plane, the beam steering can be achieved at more than 30° on the xz plane. Additionally, the proposed antenna can attain an average tilt angle of more than 10° on the yz plane. The antenna is also capable of attaining other important results, such as a fractional bandwidth of 4% at 2.5 GHz and an average gain of 2.3 dBi for all configurations. By adopting the ON/OFF condition on the embedded RF switches, the beam steering can be controlled at a certain angle, thus increasing the tilting angle of the wireless sensor networks. With such a good performance, the proposed antenna has high potential to serve as a base station in WSN applications.

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Beam Steering Monopole Antenna for Low Power Wireless Communication in WSN

2020-03-20 , Mahdir N.A.F. , Osman M.N. , Thennarasan Sabapathy , Muzammil Jusoh , Zainudin N.A.F.M.

Antenna for wireless sensor networks (WSN) application need to satisfy a number of additional properties like antenna efficiency. Since there are many WSN nodes, the use of low cost and high efficient antenna is highly important. Therefore, in this paper, a beam steering antenna resonate at 2.4 GHz with monopole element by using parasitic array technique is proposed. The parasitic array element is introduced to achieve a better gain and acts as a reflector to steer the beam to the desired degree of angles. The structure of the proposed design consists of monopole antenna as the radiating element, and to parasitic patches with the same dimension of monopole are placed next to the radiating patch. Two switches (PIN diode) are used and embedded at the back of the structure. By activating and deactivating of the switches (ON or OFF), the parasitic is either grounded or disconnected from ground. Consequently, depending on the switches configuration, the beam pattern can be steered two direction angles which 25 left or right. The simulated and measured results are presented to demonstrate the performance of the proposed antenna.

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