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1. CochleaSpecNet: An Attention-Based Dual Branch Hybrid CNN-GRU Network for Speech Emotion Recognition Using Cochleagram and Spectrogram

Author

Atkia Anika Namey, Khadija Akter, Md. Azad Hossain, and M. Ali Akber Dewan

Subjects
Speech emotion, cochleagram, spectrogram, hybrid network, multi-head attention, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Being one of the main communication medium, speech contains necessary information about the emotional state of a human. Accurate emotion recognition is crucial for enhancing human-machine interactions, highlighting the importance of a strong Speech Emotion Recognition (SER) system. SER system classifies the human emotional state based on speaker’s utterances in different catagories such as sad, happy, neutral, angry, surprise, calm and so on. This research introduces a novel SER approach that utilizes cochleagram and spectrogram features to capture relevant speech patterns for the classifier network. The network integrates a hybrid model that combines Convolutional Neural Networks (CNN) for feature extraction with Gated Recurrent Units (GRU) to handle temporal dependencies. Furthermore, to improve the performance of this network, a multi-head attention mechanism has been incorporated following the GRU layer. Despite increasing interest in SER, there is a notable lack of studies using Bangla language datasets, revealing a significant gap in current research. To address this gap, evaluation of the model has been conducted on the augmented BanglaSER (Bangla Speech Emotion Recognition) dataset in which the model has achieved a notable accuracy of 92.04% in categorizing five distinct emotions: angry, surprise, happy, neutral, and sad. Additionally, to further evaluate the performance of the SER model, English language based RAVDESS (Ryerson Audio-Visual Database of Emotional Speech) dataset has also been employed into the proposed model. This attempt has provided 82.40% accuracy in classifying eight diverse emotions that includes fear, disgust, calm along with the emotions of BanglaSER. Moreover, a comparative analysis of the proposed model with existing SER approaches is carried out to demonstrate it’s stability and robustness. The incorporation of two individual features as inputs into the attention guided hybrid neural network showcases the efficacy of the proposed SER system, offering a promising approach for precise and efficient emotion categorization from speech signals.

Published
2024
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2. SPT-Swin: A Shifted Patch Tokenization Swin Transformer for Image Classification

Author

Gazi Jannatul Ferdous, Khaleda Akhter Sathi, Md. Azad Hossain, and M. Ali Akber Dewan

Subjects
Data efficiency, image classification, linear complexity, shifted patch tokenization, swin transformer, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Recently, the transformer-based model e.g., the vision transformer (ViT) has been extensively used in computer vision tasks. The superior performance of the ViT leads to the requirement of an enormous dataset and the complexity of calculating self-attention between patches is quadratic in nature. To acknowledge these two concerns, this paper proposes a novel shifted patch tokenization swin transformer (SPT-Swin) for the image classification task. The shifted patch tokenization (SPT) compensates for the data deficiency by increasing the data samples based on spatial information of the image patches while the swin transformer provides linear computational complexity by calculating self-attention between the shifted window based patches. For model validation, the SPT-Swin framework is trained on popular benchmark image datasets such as ImageNet-1K, CIFAR-10 and CIFAR-100, and the classification accuracies are found 89.45%, 95.67% and 92.95% respectively. Moreover, the comparative analysis of the proposed model with the existing state-of-the-art models shows that the classification performances are improved by 7.05%, 4.14%, and 8.30% for the ImageNet-1K, CIFAR-10 and CIFAR-100 datasets respectively. Therefore, our proposed SPT-based data augmentation technique with the core swin transformer model could be a data-efficient linear complex-able model for future computer vision tasks.

Published
2024
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3. Stress Detection and Audio-Visual Stimuli Classification From Electroencephalogram

Author

Trishita Ghosh Troyee, Mehdi Hasan Chowdhury, Md. Fazlul Karim Khondakar, Mahmudul Hasan, Md. Azad Hossain, Quazi Delwar Hossain, and M. Ali Akber Dewan

Subjects
Brain-computer interface (BCI), electroencephalogram (EEG), mental stress, audio stimuli, visual stimuli, machine learning, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Electroencephalogram (EEG) is the graphical representation of Brain’s electrical activity. Mental stress can be detected in many ways and EEG is one of them. Regular mental stress gives rise to many mental disorders and it may cause various physiological and psychological diseases. As a result, early-stage detection of stress is very important. In this research, brain activity was recorded through EEG headset during inducing different levels of stress from audio-visual stimulus. Again, for better interaction between humans and machines, it is essential to analyze the power spectrum of the brain in response to different audio and visual stimulus. To better evaluate visual and auditory stress, an automated system is designed to differentiate among various audio and visual evoked potentials. This may further help for designing different assistive devices for the people having visual and hearing disability. In this paper, we proposed a framework to classify different levels of stress in response to audio and visual stimuli and also classified between these two stimuli by analyzing EEG signals. Raw EEG data was collected in lab environment and the necessary pre-processing steps were applied for denoising. By extracting robust features from the denoised audio and visual data, binary and multi-level stress were classified. A binary classification between audio and visual stimuli was also successfully done in this research. We achieved highest accuracy for binary stress classification 97.14% from visual stimuli, whereas we achieved 94.51% accuracy for auditory stimuli. Again, we achieved the accuracy for four level stress classification 89.59% for visual stimuli and 82.63% for audio stimuli.

Published
2024
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4. Ultra-Sensitive Visible-IR Range Fiber Based Plasmonic Sensor: A Finite-Element Analysis and Deep Learning Approach for RI Prediction

Author

Mohammad Al Mahfuz, Sumaiya Afroj, Afiquer Rahman, Md. Azad Hossain, Md. Anwar Hossain, and Md Selim Habib

Subjects
Photonic crystal fiber, surface plasmon resonance, artificial neural network, sensor, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

In this paper, a relatively simple and ultra-sensitive Photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensor is proposed for detecting different analyte refractive indices (RIs) ranging from 1.33 to 1.43 over a wide range of wavelength spectrum spanning $0.55~\mu $ m to $3.50~\mu $ m. The comprehensive finite-element simulations indicate that it is possible to achieve remarkable sensing performances such as wavelength sensitivity (WS) and figure of merit (FOM) as high as 123,000 nm/RIU and 683 RIU1, respectively, and extremely low value of wavelength resolution (WR) about $8.13\times 10^{-7}$ RIU. A novel artificial neural network (ANN) model is proposed which helps to accurately predict the RIs by carefully examining the simulation data. The mean square error (MSE) and prediction accuracy ( $R^{2}$ ) values for the ANN model are found about 0.0097 and 0.9987, respectively, indicating the high prediction capability of the proposed ANN model. Due to its exceptional sensitivity and precise detection capabilities, the proposed sensor has the potential to serve as a viable option for sensing analyte RI. Additionally, the sensor could be utilized for identifying cancerous cells and detecting urinary tract infections in humans.

Published
2024
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5. LCDEiT: A Linear Complexity Data-Efficient Image Transformer for MRI Brain Tumor Classification

Author

Gazi Jannatul Ferdous, Khaleda Akhter Sathi, Md. Azad Hossain, Mohammed Moshiul Hoque, and M. Ali Akber Dewan

Subjects
Brain tumor, classification, external attention, MRI, transformer, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

Current deep learning-assisted brain tumor classification models sustain inductive bias and parameter dependency problems for extracting texture-based image information. Thereby concerning these problems, the recent development of the vision transformer model has substituted the DL model for classification tasks. However, the high performance of the vision transformer model depends on a large-scale dataset as well as self-attention calculations between the number of image patches which result in a quadratic computational complexity. To address these problems, the vision transformer must be data-efficient to be well-trained with a limited amount of data, and the computational complexity must be linear with the number of image patches. Consequently, this paper presents a novel linear-complexity data-efficient image transformer called LCDEiT for training with small-size datasets by using a teacher-student strategy and linear computational complexity concerning the number of patches using an external attention mechanism. The teacher model comprised a custom gated-pooled convolutional neural network to provide knowledge to the transformer-based student model for the classification of MRI brain tumors. The average classification accuracy and F1-score for two benchmark datasets including Figshare and BraTS-21 are found 98.11% and 97.86% and 93.69% and 93.68% respectively. The results indicate that the proposed model could have a great impact on medical imaging-based diagnosis where data availability and faster computations are the main concern.

Published
2023
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6. ViTab Transformer Framework for Predicting Induced Electric Field and Focality in Transcranial Magnetic Stimulation

Author

Barna Ghosh, Khaleda Akhter Sathi, Md. Kamal Hosain, Md. Azad Hossain, M. Ali Akber Dewan, and Abbas Z. Kouzani

Subjects
Transcranial magnetic stimulation, electric field, focality, transformer, MRI images, regression, Medical technology, R855-855.5, Therapeutics. Pharmacology, RM1-950
Abstract

Transcranial magnetic stimulation is an electromagnetic induction-based non-invasive therapeutic technique for neurological diseases. For finding new clinical applications and enhancing the efficacy of TMS in existing neurological disorders, the current study focuses on a deep learning-based prediction model as an alternative to time-consuming electromagnetic (EM) simulation software. The main bottleneck of the existing prediction models is to consider very few input parameters of a standard coil such as coil type and coil position for predicting an output of electric field value. To overcome this limitation, a transformer-based prediction model titled as ViTab transformer is developed in this work to predict electric field (E-max), focality or area of stmulation (S-half), and volume of stimulation (V-half) by considering several input parameters such as sources of MRI images, types of coils, coil position, rate of change of current, brain tissues conductivity, and coil distance from the scalp. The proposed framework consists of a vision and a tab transformer to handle both image and tabular-type data. The prediction performance of the offered model is evaluated in terms of coefficient determination, R2 score, for E-max, V-half, and S-half in the testing phase. The obtained result in terms of R2 score for E-max, V-half, and S-half are found 0.97, 0.87, and 0.90 respectively. The results indicate that the suggested ViTab transformer model can predict electric field as well as focality more accurately than the current state-of-the-art methods. The reduced computational time, as well as efficient prediction accuracy, resembles that ViTab transformer can assist the neuroscientist and neurosurgeon prior to providing superior TMS treatment in near future.

Published
2023
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7. A Deep Neural Network Model for Predicting Electric Fields Induced by Transcranial Magnetic Stimulation Coil

Author

Khaleda Akhter Sathi, Md. Azad Hossain, Md. Kamal Hosain, Nguyen Hoang Hai, and Md. Anwar Hossain

Subjects
Deep neural network, deep learning, electric field, magnetic coil, transcranial magnetic stimulation, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

This article proposes a deep neural network (DNN) model to predict the electric field induced by a transcranial magnetic stimulation (TMS) coil under high-amplitude and low-frequency current pulse conditions. The DNN model is comprised of an input layer with 6 neurons, three non-linear hidden layers with a total of 1088 neurons, and a linear single output layer. The model is developed in Google Colaboratory environment with TensorFlow framework using six features including coil turns of single wing, coil thickness, coil diameter, distance between two wings, distance between head and coil position, and angle between two wings of coil as the inputs and electric field as the output. The model performance is evaluated based on four verification statistic metrics such as coefficient of determination (R2), mean squared error (MSE), mean absolute error (MAE), and root mean squared error (RMSE) between the simulated and predicted values. The proposed model provides an adequate performance with $\text{R}^{2} =0.766$ , MSE = 0.184, MAE = 0.262, and RMSE = 0.429 in the testing stage. Therefore, the model can successfully predict the electric field in an assembly TMS coil without the aid of electromagnetic simulation software that suffers from an extensive computational cost.

Published
2021
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20. Designing of a Both-Sided MIC Starfish Microstrip Array Antenna for K-Band Application

Author

Abu Hena Murshed, Eisuke Nishiyama, Md. Azad Hossain, Muhammad Asad Rahman, and Ichihiko Toyoda

Subjects
Physics, Microstrip antenna, Optics, business.industry, Main lobe, K band, Impedance matching, Array data structure, Antenna (radio), Reflection coefficient, business, Microstrip
Abstract

This paper represents a 2×2 microstrip starfish array antenna that shows a linearly polarized electromagnetic wave with high gain characteristics. The proposed antenna operates within K-band which is a suitable candidate for radar as well as satellite applications. This proposed antenna employs Both-sided MIC (Microwave Integrated Circuit) technology to get around of impedance matching problem of the conventional array antenna. The proposed antenna is excited with microstrip feed where the feeding network consists of parallel and series branches of both microstrip and slot line. Teflon glass fiber (e r = 2.1) of 0.8 mm thickness is used as a substrate where the main feed network is arranged upon it. Antenna shows a minimum reflection coefficient gain of -63 dB and the main lobe possesses a high magnitude of around 10.9 dBi at 18.75 GHz. Antenna shows impedance bandwidth of 230 MHz and more than 96% of total efficiency over the desired K-band of the frequency spectrum. CST Microwave Studio suite is used to explore all the simulated results of the proposed 4-element array antenna. The basic mechanism along with simulated results of the proposed array structure is discussed in this article.

Published
2021
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22. Design of Double Inverted F-shaped Dual Wideband Microstrip Antenna for WLAN, WiMAX Wireless Communication

Author

Md. Azizul Hakim, Adnan Basir Patwary, and Md. Azad Hossain

Subjects
Physics, business.industry, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Electrical engineering, WiMAX, Directivity, Microstrip antenna, Inverted-F antenna, Hardware_GENERAL, Return loss, Multi-band device, Antenna (radio), Wideband, business
Abstract

This work depicts a dual band microstrip antenna with linear polarization and single line feed. The designed antenna is resonant at 2.44 GHz and 5.57 GHz for WLAN and WiMAX application respectively. The dual band mechanism is achieved by combining two U-shaped patches on a same plane and finally forming an inverted F antenna through modifying the length of patches. The simulated S(1,1) parameter of the designed dual band antenna are -39.125dB and -41.073dB. The designed antenna has 10dB impedance bandwidth of 833 MHz (2.621-3.094 GHz) and 550 MHz (5.482-6.032 GHz) respectively to cover WLAN and WiMAX operating bands. Advanced Design System (ADS) software was used to design and simulate the performance characteristics. The designed antenna in this work has shown improved return loss, directivity, bandwidth and power efficiency with respect to similar antenna related works.

Published
2021
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23. Frequency Tunability Study of an SRR and SNG Metamaterial Integrated UWB Antenna

Author

Nipa Dhar, Muhammad Asad Rahman, and Md. Azad Hossain

Subjects
Physics, Reconfigurable antenna, business.industry, 020208 electrical & electronic engineering, Metamaterial, 020206 networking & telecommunications, 02 engineering and technology, law.invention, Resonator, Optics, Cognitive radio, law, 0202 electrical engineering, electronic engineering, information engineering, Antenna (radio), business, Electrical impedance, Band rejection, Diode
Abstract

A new technique to design a metamaterial (MTM) inspired frequency reconfigurable ultra-wideband (UWB) antenna is presented in this paper. The proposed antenna comprises a circular disc UWB antenna having two MTM unit cells. MTMs are placed at a slant of ±30° from the centre of the circular patch and two diodes (D1, D2) are used to switching them to the circular disc. The circular disc conventional UWB antenna can operate from 3–10 GHz. The magnetic resonance of a circular split-ring resonator (SRR) from 1.75–2 GHz and two epsilon negative bands of a single negative (SNG) MTM from 1.54–2 GHz and 3.4–4.2 GHz are employed to achieve the frequency tuning purpose. When the SRR is connected to the circular disc, it offers additional impedance BW in the lower frequency region (1.8–2.9 GHz) along with UWB operation. Another narrow band feature at L1 GPS band beside the UWB operations can also be accessed by switching an SNG MTM to the circular disc. Moreover, the proposed antenna demonstrates the band rejection capability ranges from 3.2–3.8 GHz and 4.1–4.7 GHz. Also, the simulated gain at operating bands 1.51–1.62/1.8–10/3–10/4.8–10 GHz are 1.7–2.75/1.75–2.8/2.95–2.75/2.15–4.06 dBi. So, the proposed MTM motivated frequency reconfigurable antenna could be a potential candidate for GPS, UWB, and cognitive radio (CR) system.

Published
2020
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24. Design and Characterization of Miniaturized Implantable PIFA Antenna for MICS Band Application

Author

Md. Azad Hossain, Saife Shuhaib Md. Enan, and Arif Istiaque

Subjects
Materials science, business.industry, Bandwidth (signal processing), Electrical engineering, Specific absorption rate, computer.software_genre, Imaging phantom, Simulation software, Miniaturization, Return loss, Wireless, business, computer, Biotelemetry
Abstract

This study concerns with the miniaturization of a microstrip patch antenna using several miniaturization techniques for the application in biotelemetry at the Medical Implant Communication Service (MICS) (402–405 MHz) band. The primary intention is to be able to use this radiating structure as a means of wireless communication and power transmission to a pacemaker system. The optimized structure has dimensions of 12.8x12.8x0.8mm3 and a measured operating frequency of 403 MHz with a bandwidth of 10 MHz observed at return loss of -10dB. The proposed antenna volume is 0.217% of equivalent rectangular patch which resonates at 403MHz. In addition, the measured Specific Absorption Rate (SAR) using a phantom model was 1.38 w/kg for 4mW of excitation power delivered to the structure. The design parameters were evaluated on a substrate of FR-4 using the simulation software CST Studio Suit.

Published
2020
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25. A Transparent Conductive Material Based Circularly Polarized Nano-antenna for THz Applications

Author

Md. Sarwar Uddin Chowdhury, Ahmed Toaha Mobashsher, Md. Azad Hossain, and Muhammad Asad Rahman

Subjects
Materials science, business.industry, Terahertz radiation, Bandwidth (signal processing), Carbon nanotube, Radiation, Communications system, Indium tin oxide, law.invention, law, Optoelectronics, business, Circular polarization, Data transmission
Abstract

In this paper, an optically transparent circularly polarized E-shaped antenna is presented for THz applications. THz antennas are important for inter-satellite communication systems to enable the adequate spatial resolution, wide bandwidth, superior data rates and highly directional beam with secured data transmission. Due to the non-ionizing nature and penetration capability of THz radiation, the application of THz antenna is gaining momentum in space communications and security systems. Transparent conductive material namely indium tin oxide is deployed as patch. Due to low conductivity, the performance of ITO based antenna is slightly reduced which is overcome by loading another transparent highly conductive material namely carbon nanotube as cover over the patch. Circular polarization is acquired by introducing orthogonality between two resonating degenerate current modes with the aid of the two unequal parallel slits of E-shaped patch along with inserted E-shaped and I-shaped slots into the patch. 10-dB impedance bandwidth of 22.2% and 3-dB axial ratio bandwidth of 9.14% are achieved with good radiation performance which makes this simple nano-antenna suitable for THz applications.

Published
2020
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26. Design of a 5G Compatible Two-Element Dual-Band Circularly Polarized MIMO Antenna

Author

Muhammad Asad Rahman, Ichihiko Toyoda, Md. Azad Hossain, Swarup Chakraborty, and Eisuke Nishiyama

Subjects
Coupling, Physics, Channel capacity, Optics, business.industry, MIMO, Feed line, Multi-band device, Antenna (radio), business, Circular polarization, Computer Science::Information Theory, Ground plane
Abstract

This paper proposes a 2-element dual-band MIMO antenna with circular polarization (CP). The antenna can operate at two 5G bands, 3.6-3.8 GHz and 4.8-5.0 GHz. The MIMO arrangement consists of two single elliptical shaped nonuniform width slot antennas. The unequal feed line mechanism is used to sense CP where two parallel L-shaped arms of different length are employed to attain dual-band. Reduction of the surface wave coupling is achieved by inserting three strip lines on the ground plane between the antenna elements by applying defected ground technique. The antenna provides good isolation (less than −20 dB) and CP radiation in both bands. Hence, envelope correlation coefficient (ECC) and channel capacity loss (CCL) are less than 0.0005 and 0.05 b/sec/Hz, respectively. These results prepare the MIMO antenna suitable for 5G wireless applications.

Published
2019
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27. A Design of a Metamaterial Integrated Triple Band Antenna for Wireless Applications

Author

Nipa Dhar, Ahmed Toaha Mobashsher, Muhammad Asad Rahman, Proma Dutta, and Md. Azad Hossain

Subjects
Physics, business.industry, 020208 electrical & electronic engineering, Bandwidth (signal processing), Metamaterial, 020206 networking & telecommunications, 02 engineering and technology, Microstrip, Radiation pattern, Split-ring resonator, Optics, 0202 electrical engineering, electronic engineering, information engineering, Reflection coefficient, business, Electrical impedance, Ground plane
Abstract

This paper represents a metamaterial (MTM) integrated antenna for multi-band operation. MTMs are integrated on the top and bottom sides of a slot-ring antenna. The basic slot-ring antenna operates at 2.4 GHz. A single complementary split ring resonator (CSRR) is placed on the ground plane and a circular shaped split ring resonator (SRR) is integrated on the top of the substrate. Integration of CSRR gives rise to a new resonant frequency at 1.5 GHz. After using SRR, a third band generates at 3.1 GHz. By using this structure, a single antenna can cover three operating bands. A microstrip line is used to feed the antenna. The triple band antenna is compact because MTM unit cells size is smaller than their wavelength used to produce resonance at a lower frequency. To analyze the performance of the proposed antenna reflection coefficient, radiation pattern, and gain are analyzed. The simulated gains are 0.71 dBi, 2.9 dBi, and 3.2 dBi corresponding to bands of 1.5 GHz, 2.4 GHz, and 3.1 GHz, respectively. The impedance bandwidths are 1.33%, 9.17%, 5.5% at the 1.5/2.4/3.1 GHz, respectively. Good separation between co- and cross-polarizations is achieved. The three operating bands at 1.5/2.4/3.1 GHz support the allotted bands for GPS, WLAN and RADAR applications.

Published
2019
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28. Design and Performance Studies of a MIMO Antenna With Circular Polarization Diversity for 5G Applications

Author

Ahmed Toaha Mobashsher, Swarup Chakraborty, Ichihiko Toyoda, Eisuke Nishiyama, Md. Azad Hossain, and Muhammad Asad Rahman

Subjects
Physics, Optics, business.industry, Axial ratio, MIMO, Slot antenna, Antenna (radio), business, Microstrip, Circular polarization, Radiation pattern, Ground plane
Abstract

An innovative 2-element multiple input multiple output (MIMO) antenna with the circular polarization (CP) diversity is proposed in this paper with an intention to use in the sub−6 GHz spectrum (3.6–3.8 GHz) for 5G wireless applications. A microstrip line fed slot antenna is working as a single element for the MIMO arrangement. An elliptical shaped slot and the unequal feed lines mechanism are used to sense CP for every element. For CP diversity, mirror operation between the antenna elements is performed. A rectangular slot line in the ground plane is inserted to realize better isolation between the antenna elements. The MIMO antenna provides good isolation < -25 dB between the antenna elements in 5G operating frequency band of 3.6-3.8 GHz. Considering 5 dBic gain as well as axial ratio (AR) less than 0.5 dB, this antenna shows promising CP radiation pattern. Moreover, result of envelope correlation coefficient (ECC) (< 0.002) and channel capacity loss (CCL) less than 0.3 b/sec/Hz make it suitable for fifth generation wireless applications.

Published
2019
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29. Design of an ITO Based CNT Coated Transparent Nano Patch Antenna Assisted by Characteristic Mode Analysis

Author

Ahmed Toaha Mobashsher, Md. Azad Hossain, Md. Sarwar Uddin Chowdhury, and Muhammad Asad Rahman

Subjects
Patch antenna, Materials science, Terahertz radiation, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, 020206 networking & telecommunications, 02 engineering and technology, Radiation, Antenna efficiency, 03 medical and health sciences, 0302 clinical medicine, Characteristic mode analysis, Nano, 0202 electrical engineering, electronic engineering, information engineering, Optoelectronics, Antenna (radio), Thin film, business, 030217 neurology & neurosurgery, Computer Science::Information Theory
Abstract

An Indium-doped Tin Oxide (ITO) based optically transparent nano-antenna is presented in this paper. E-shaped patch is used to resonate at 0.76 THz. Despite of high fractional bandwidth, the radiation efficiency as well as gain of the ITO based antennas are low due to high resistivity and low conductivity of ITO thin films. To overcome this limitation, carbon nano tube (CNT) is used as cover over radiating patch of the proposed antenna. As a result, due to high conductivity of CNT, along with gain and efficiency, the fractional bandwidth of the proposed antenna is also increased. Characteristic mode analysis (CMA) is carried out to provide more insightful physical characteristics of the proposed antenna. It helps to understand the structural optimization and to determine the operating frequency. Moreover, a copper based non-transparent E-shaped patch antenna, resonated at 0.76 THz is also designed to compare with the proposed antenna. The proposed antenna has fractional bandwidth of 21% which is much better than conventional patch antenna and some previous transparent antennas. A peak gain of 4.9 dBi is obtained at 0.76 THz with good radiation performance. The designed antenna is suitable for satellite communication because of its broad bandwidth, reasonable radiation efficiency, sufficient gain, light weight and compactness.

Published
2019
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30. Bandwidth-Enhanced Metamaterial Integrated Antenna for Wireless Applications

Author

Nipa Dhar, Ahmed Toaha Mobashsher, Md. Azad Hossain, and Muhammad Asad Rahman

Subjects
Physics, business.industry, 020208 electrical & electronic engineering, Bandwidth (signal processing), Electrical engineering, Metamaterial, 020206 networking & telecommunications, 02 engineering and technology, law.invention, Split-ring resonator, law, 0202 electrical engineering, electronic engineering, information engineering, Miniaturization, Radar, business, Monopole antenna, Ground plane, Metamaterial antenna
Abstract

This paper represents a metamaterial (MTM) integrated bandwidth-enhanced antenna for modern wireless communication systems. The MTM ultra wide-band (UWB) antenna comprises of two unit cells on the top of the substrate, a circular disc monopole, and a partial ground plane. The unit cell consists of a split ring resonator. Without unit cells, the monopole antenna can operate in a wide band of impedance bandwidth of 7.5 GHz, corresponding to a percentage bandwidth of 120% (2.5-10 GHz). After the integration of MTMs, the proposed antenna can operate from 1.5-10 GHz range with a percentage bandwidth of 147.8%. So, MTMs integration can provide additional operation at 1.5-2.5 GHz, thus the bandwidth is broadened. As the dimensions of the unit cells are much smaller than the resonant frequency, miniaturization of the antenna size can be achieved. Different simulated antenna performance parameters such as reflection coefficients, radiation patterns, and gain are analyzed. The simulated gains of the proposed design at 1.5, 2.4, 5.8 and 10 GHz are 1.17 dBi, 2.18 dBi, 3.6 dBi, and 4.05 dBi, respectively. The proposed antenna could be a potential contender for different remote correspondence frameworks, for example, GPS, Wi-Fi, WLAN, and RADAR.

Published
2019
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31. Design and Performance Studies of an Elliptical Slot Circular Polarization Antenna for C-Band Wireless Applications

Author

Muhammad Asad Rahman, Md. Azad Hossain, and Swarup Chakraborty

Subjects
Physics, business.industry, Axial ratio, 020208 electrical & electronic engineering, 020206 networking & telecommunications, 02 engineering and technology, Directivity, Microstrip, Optics, 0202 electrical engineering, electronic engineering, information engineering, Return loss, Standing wave ratio, business, Monopole antenna, Circular polarization, Ground plane
Abstract

A novel and subtle design of a circularly polarized microstrip line feed elliptical slot monopole antenna with an intention to use in C-Band (4–8 GHz) is proposed in this communication. Due to notable as well as remarkable performances, this small and compact antenna with ample applications in the arena of wireless communication upholds its strong position among the previous work of similar types. For designing and simulating the proposed antenna for exploration of its feasibility to use in the C-band wireless applications especially satellite-based communication system, CST MW studio is used. Different categories of calculations and performance studies have been performed while maintaining a suitable environment of free space for wireless communication. The antenna with overall dimension of $\pmb{50}\ \mathbf{mm}\ \pmb{\times \ 30} \ \mathbf{mm} \ \pmb{\times 0.836}$ mm, where the substrate is used is Teflon and Copper is used as radiating patch as well as ground plane, is placed for evaluating its performance in respect of return loss, radiation and total efficiency, VSWR, gain, directivity, direction of surface current, axial ratio (AR) bandwidth, and reduction of cross polarization (XP). An impressive return loss (-41.7 dB) at the resonance frequency and suppression of XP of 33.50 dB have been accomplished with other marvelous results.

Published
2019
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32. Design of a Ladybug Shaped Circular Polarized Microstrip Antenna at 5.8 GHz as Microwave Power Transmitter to a MAV

Author

Sabrina Abedin, Adnan Basir Patwary, and Md. Azad Hossain

Subjects
Physics, business.industry, Axial ratio, 020208 electrical & electronic engineering, 020206 networking & telecommunications, 02 engineering and technology, Microstrip, Radiation pattern, Microstrip antenna, Optics, 0202 electrical engineering, electronic engineering, information engineering, Return loss, Antenna (radio), business, Omnidirectional antenna, Circular polarization
Abstract

This paper is based on a circular polarized microstrip patch antenna which is designed for microwave power transmission with resonating frequency of 5.8 GHz. The radiating patch of the antenna is based on a dual feed elliptical patch which is modified by adding quarter wavelength resonators and circular slots. The resultant patch resembles to a ladybug and hence the name “Ladybug antenna”. The designed antenna has a gain of 6.88 dB and return loss of 25dB. It has 0.48 dB axial ratio at 5.8 GHz which shows that it has good circular polarization. The Ladybug antenna has omnidirectional radiation pattern which is suitable for short range MPT operation of Micro Aerial Vehicles (MAV).

Published
2019
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33. A Star-Fish Shaped Compact Dual band Antenna for Millimeter Wave Band Applications

Author

Md. Azad Hossain, Piyas Chowdhury, and Mumtahina Khan Mumu

Subjects
Physics, business.industry, Bandwidth (signal processing), Astrophysics::Instrumentation and Methods for Astrophysics, 020302 automobile design & engineering, 020206 networking & telecommunications, 02 engineering and technology, Handset, law.invention, Microstrip antenna, Optics, 0203 mechanical engineering, W band, law, Extremely high frequency, 0202 electrical engineering, electronic engineering, information engineering, Return loss, Multi-band device, business, Astrophysics::Galaxy Astrophysics, Computer Science::Information Theory, V band
Abstract

In this paper a star fish shaped microstrip patch antenna is proposed and its design procedure and characteristics are analyzed. The shape of the antenna patch is similar to a star fish, therefore the antenna is called Star fish antenna. The proposed antenna is able to provide dual band operation in V band (40–52 GHz) and W band (77–95 GHz) which lie in the range of millimeter wave frequency. The proposed antenna has 8 branches of unequal length in order to achieve wide bandwidth in millimeter wave range. Each of the branch resonates at different frequency which ultimately results in a wide bandwidth of 30 GHz with an efficient gain of 7.9026 dBi and highly reduced return loss. Designed antenna has a very compact dimensions of 9×9×2.03 mm3, thus it can be easily fabricated with small handset devices.

Published
2019
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34. A Sawtooth Shaped CPW Fed UWB Microstrip Patch Antenna for Biotelemetry Applications

Author

Md. Siddat Bin Nesar, Md. Azad Hossain, Akash Biswas, Md. Abdul Muktadir, Nishako Chakma, and Piyas Chowdhury

Subjects
Physics, Robustness (computer science), Acoustics, Coplanar waveguide, Return loss, Microstrip patch antenna, Slot antenna, Sawtooth wave, Directivity, Biotelemetry
Abstract

A novel and simple sawtooth shaped Ultra-Wide band (UWB) antenna design with coplanar waveguide feeding for biotelemetry applications have been suggested in this research. A unique model & noteworthy enactment of the proposed antenna validates its robustness among the other antenna of similar types. This antenna covers almost 83.7% of the UWB in between 3.1 to 10.6 GHz, having an impressive return loss below 13 dB throughout the whole range. There are four resonating frequencies within the range with a maximum return loss of 26.769 dB. Obtained maximum directivity and gain for the projected antenna are 7.635 dBi and 7.641 dBi respectively. The optimized dimension of the antenna with a simple structure of sawtooth shape is 49 mm ⨯ 42.5 mm ⨯ 1.64 mm which can be easily integrated with handheld devices for UWB applications. Several calculations and performance analysis have been done using Advanced Design System (ADS) to make the antenna more invigorated for practical use.

Published
2018
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35. Wheel therapy chair: A smart system for disabled person with therapy facility

Author

Ali Mohammed Jobayer, Avradip Paul, Md. Azad Hossain, Swarup Chakraborty, and Md. Mamunur Rahman

Subjects
0209 industrial biotechnology, Engineering, Smart system, business.industry, Human life, 020208 electrical & electronic engineering, Control (management), 02 engineering and technology, 020901 industrial engineering & automation, Wheelchair, Human–computer interaction, Obstacle, Arduino, Joystick, 0202 electrical engineering, electronic engineering, information engineering, business, Simulation
Abstract

Each and every person in this world has a desire to live a normal human life but accidents, diseases, elder-ship make their desire into disability. Moreover, there are lots of handicaps and elders as well as the number of paralyzed people are increasing day by day. They always need another person in moving and have to go under some physical therapies under the guidance of a therapist to recuperate their strain back. In this paper the proposed system helps them to move freely & safely and also takes the activities of a therapist in a cost effective manner. This system is a combination of different controlling features, has the ability to detect obstacle and provides few kinds of therapies. A smart wheelchair is developed by using voice recognition system to control the movement of wheelchair and also with Arduino interfaced joystick. Besides, an ultrasound system provides the facility of automatic obstacle detection. The aim of research is to compact many facilities in a single wheelchair at low cost.

Published
2017
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38. Design of an orthogonal feed circularly polarized microstrip array antenna suitable for large scale extensible arrays

Author

Eisuke Nishiyama, Ichihiko Toyoda, Quazi Delwar Hossain, Md. Azad Hossain, and Muhammad Asad Rahman

Subjects
Patch antenna, Physics, business.industry, Reflective array antenna, 020208 electrical & electronic engineering, Turnstile antenna, 020206 networking & telecommunications, Slot antenna, 02 engineering and technology, Collinear antenna array, law.invention, Microstrip antenna, Optics, law, 0202 electrical engineering, electronic engineering, information engineering, Dipole antenna, Antenna feed, business
Abstract

This paper presents a circularly polarized 1×2 array antenna for X-band applications. Both-sided MIC technology is effectively used to design this array antenna as the array antenna consists of both microstrip lines and slot lines to realize the feed network. Patch elements and microstrip lines are placed on the top surface of the substrate and slot lines on the reverse surface (ground plan) of the substrate. Each of the patches is excited by two orthogonal feed lines. One of the feed lines is ahead by an odd multiple of quarter wavelength than the other feed line. This strategy makes the each patch circularly polarized. The impedance bandwidth is about 630 MHz and the 3-dB axial ratio bandwidth is more than 1%. This array antenna is very suitable to make large scale extensible array antennas by using it as a unit array.

Published
2016
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39. Design of an x-band microstrip array antenna for circular polarization

Author

Ichihiko Toyoda, Eisuke Nishiyama, Md. Azad Hossain, Quazi Delwar Hossain, and Muhammad Asad Rahman

Subjects
Physics, Patch antenna, Coaxial antenna, business.industry, Antenna measurement, Turnstile antenna, law.invention, Microstrip antenna, Optics, law, Dipole antenna, Antenna feed, Antenna (radio), business, Computer Science::Information Theory
Abstract

In this paper, the design of a circularly polarized array antenna with 9.56 dBi of gain at 10 GHz frequency is presented. The proposed antenna consists of a 2×2 array antenna with feed network where all microstrip patches are linearly polarized. “Both-Sided MIC Technology” is used to design the proposed array antenna. The simulated return loss of the proposed array antenna is less than −35dB. The 3 dB axial ratio bandwidth of 2.21% is obtained. The unequal feed line is used in order to realize 90° phase difference between the linearly polarized patches. Therefore, the circular polarization is realized by the combination of linearly polarized patches and unequal feed line. The structure and the basic behavior along with the simulation results of the proposed linearly polarized array antenna are demonstrated in this paper.

Published
2014
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40. Design of a dual circular polarization microstrip patch array antenna

Author

Quazi Delwar Hossain, Md. Azad Hossain, Ichihiko Toyoda, Muhammad Asad Rahman, Md. Moshiul Haque, and Eisuke Nishiyama

Subjects
Folded inverted conformal antenna, Physics, Patch antenna, Microstrip antenna, Optics, business.industry, Antenna measurement, Antenna (radio), business, Microstrip, Circular polarization, Dual (category theory)
Published
2014
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41. Design of a circular polarization array antenna with dual-orthogonal feed circuit

Author

Quazi Delwar Hossain, Piyas Chowdhury, Md. Azad Hossain, and Muhammad Asad Rahman

Subjects
Physics, Patch antenna, Coaxial antenna, business.industry, Antenna measurement, Turnstile antenna, Antenna factor, law.invention, Microstrip antenna, Optics, law, Antenna feed, Dipole antenna, business
Abstract

In this paper, the design of a circularly polarized array antenna at 10 GHz frequency is presented. The proposed antenna consists of a 1×2 array antenna with feed circuit. To realize circular polarization, dual-orthogonal feed circuit is used that excites two orthogonal modes with equal amplitude but quadrature in phase. Feed circuit is designed using microstrip lines and slot lines where microstrip lines are placed on the top surface of the substrate and slot lines on the reverse side of the substrate. The feed point is chosen in such a way that it provides the each patch element two RF signals with 90° phase difference. Therefore, the circular polarization is realized by employing microstrip-slot feed circuit. “Both-Sided MIC Technology” is used to design the proposed array antenna as it gives flexibility in the design process. The simulated return loss of the proposed array antenna is less than -45 dB at the design frequency. The 3 dB axial ratio bandwidth of 0.8% is obtained. The structure and the basic behavior along with the simulation results of the proposed circularly polarized array antenna are demonstrated in this paper.

Published
2014
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42. Design of a circular polarization array antenna using linear polarization patches

Author

Quazi Delwar Hossain, Muhammad Asad Rahman, and Md. Azad Hossain

Subjects
Patch antenna, Microstrip antenna, Materials science, Optics, Coaxial antenna, business.industry, Electronic engineering, Feed line, Turnstile antenna, Antenna feed, Antenna (radio), business, Collinear antenna array
Abstract

This paper presents a new circularly polarized array antenna using linearly polarized microstrip patches with a gain of 7.47 dBi. The array structure consists of four square patch antennas with feed network. The feed network is designed using microstrip lines on the obverse side of the dielectric substrate and slot line on the reverse side of the substrate. The Teflon glass fiber substrate is used with a permittivity of 2.15. The design frequency of the proposed array antenna is 10 GHz where simulated return loss is less than -45dB. The unequal feed line is used in order to realize 90° phase difference between the linearly polarized patches. Therefore, the circular polarization is realized by the combination of linearly polarized patches and unequal feed line. Advanced Design Systems (ADS) by Agilent Technologies is used for the simulation of the proposed array antenna.

Published
2014
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43. Design of a circular polarization switchable microstrip array antenna using magic-T bias circuit

Author

Ichihiko Toyoda, Azad Hossain, Quazi Delwar Hossain, Eisuke Nishiyama, and Piyas Chowdhury

Subjects
Patch antenna, Physics, Coaxial antenna, Loop antenna, business.industry, Antenna measurement, Electrical engineering, law.invention, Antenna efficiency, Microstrip antenna, law, Optoelectronics, Antenna feed, Dipole antenna, business
Abstract

In this paper, a 4-element circular polarization switchable patch array antenna is proposed. The array antenna is realized by the successful employment of the both-sided MIC technology, where the odd and even mode of the slot line and microstrip lines are used for the realization of the orthogonal feed and magic-T switching circuit respectively. The advantage of the magic-T circuit is the excellent isolation between the RF signal and the switching signal. In order to realize the polarization switching, two switching diodes are integrated with each patch elements. Unequal feed line is introduced to realize 90° phase difference between the patch elements and this way, circular polarization switchable array antenna can be realized. The array antenna unit is realized in very simple and compact structure as all the antenna elements, feeding circuit and switching circuit are arranged on both sides of a Teflon glass fiber substrate. The structure and the basic behavior of the circular polarization switchable array antenna are demonstrated in this paper. In addition, the simulated S-parameters and the phase difference of the feed circuit are explained.

Published
2014
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44. Single fed orthogonal linear polarization switchable microstrip planar antenna

Author

Eisuke Nishiyama, Md. Azad Hossain, Mohendro Kumar Ghosh, and Ichihiko Toyoda

Subjects
Physics, Patch antenna, Coaxial antenna, business.industry, Antenna aperture, Antenna measurement, Astrophysics::Instrumentation and Methods for Astrophysics, Physics::Optics, Antenna factor, Folded inverted conformal antenna, Microstrip antenna, Optics, business, Monopole antenna, Computer Science::Information Theory
Abstract

In this paper, a concept and investigation of orthogonal linear polarization switchable planar antenna is proposed. In order to switch the polarization axis, four switching diodes are loaded on the upper plane of the antenna. The boundary condition of the planar antenna is controlled by the ON/OFF condition of the diodes. The antenna can switch the polarization at ±45 deg. □ and 0 & 90 deg., depending on the polarity of the bias voltage and the position of the diodes. The FDTD method introduced by Yee is used to simulate the antenna which is followed by the experimental investigation.

Published
2012
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45. Estimation of Manning's roughness coefficient distribution for hydrodynamic model using remotely sensed land cover features

Author

A. K. M. Azad Hossain, Xiabo Chao, and Yafei Jia

Subjects
Meteorology, Remote sensing (archaeology), Thematic Mapper, Satellite imagery, Satellite, Land cover, Normalized Difference Vegetation Index, Geology, Remote sensing, Open-channel flow, Panchromatic film
Abstract

This research explores the potential of remote sensing techniques to derive distributed Manning's roughness coefficient (Manning's n) for the use in hydrodynamic models for numerical simulation of open channel flow in natural channels and flood plains. Normalized Difference Vegetation Index (NDVI) based land use land cover (LU/LC) data was generated using the Landsat 5 Thematic Mapper (TM) and Advance Land Observing Satellite (ALOS) Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) imagery. Manning's n were obtained from published literature for different features in flood plains and correlated with the remote sensing derived LU/LC features. CCHE2D model, developed by the National Center for Computational Hydroscience and Engineering (NCCHE), at The University of Mississippi, for simulating two dimensional depth-averaged unsteady flow and sediment transport was used to validate the remote sensing derived distributed Manning's n for channel flow calculation. Results obtained from this research indicate that satellite imagery derived LU/LC data has potential to be used to improve hydrodynamic model simulation by providing distributed Manning's roughness coefficient for respective model domains.

Published
2009
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46. Evaluating the Potential of VI-LST Triangle Model for Quantitative Estimation of Soil Moisture using Optical Imagery

Author

Greg Easson and A. K. M. Azad Hossain

Subjects
Moisture, Environmental science, Soil science, Moderate-resolution imaging spectroradiometer, Vegetation Index, Water content, Image resolution, Triangle model, Reflectivity, Data modeling, Remote sensing
Abstract

This research evaluates the potential of the vegetation index (VI) - land surface (LST) triangle model for quantitative soil moisture study using Moderate Resolution Imaging Spectroradiometer (MODIS) data in a semi-arid environment. The preliminary results indicate that the VI-LST triangle model has potential to be used for quantitative soil moisture estimation by optical imagery if combined with a reference soil moisture data. The Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) provides quantitative soil moisture estimation at 25 km spatial resolution. AMSR-E soil moisture information can be used in the VI-LST triangle model in conjunction with MODIS reflectance and thermal data to estimate soil moisture at the spatial resolution of MODIS (1 km).

Published
2008
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