http://103.99.128.19:8080/xmlui/handle/123456789/70 ETE 2026-04-19T09:22:59Z http://103.99.128.19:8080/xmlui/handle/123456789/512 Title: OPCNet: An optimized parallel convolutional neural network for classification of satellite imagery. Authors: Tumpa, Priyanti Paul Abstract: Satellite image classification is crucial for various applications, driving advancements in Convolution Neural Networks (CNNs). While CNNs have proven effective, deep models often encounter overfitting issues as the network's depth increases since the model has to learn many parameters. Besides this, traditional CNNs have the inherent difficulty in extracting fine-grained details and broader patterns simultaneously. To overcome these challenges, this research presents a novel approach using an optimized parallel CNN (OPCNet) architecture with an SVM classifier to classify satellite images. Each branch within the parallel network is designed for specific resolution characteristics, spanning from low (emphasizing broader patterns) to high (capturing fine-grained details), enabling the simultaneous extraction of a comprehensive set of features without increasing network depth. The OPCNet incorporates a dilation factor to expand the network's receptive field without increasing parameters, and a dropout layer is introduced to mitigate overfitting. Evaluation of two public datasets (EuroSAT dataset and RSI-CB256 dataset) demonstrates remarkable accuracy rates of 97.91% and 99.8%, surpassing previous state-of-the-art models. Finally, OPCNet, with less than 1 million parameters, outperforms high-parameter models by effectively addressing overfitting issues, showcasing exceptional performance in satellite image classification. Description: Thesis ETE for master of science 2024-05-21T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/505 Title: SINGLE-FEED DUAL BEAM SWITCHABLE ARRAY ANTENNA FOR ISM BAND APPLICATION Authors: Akther, Naznin Abstract: This manuscript proposes one single-feed dual-beam switchable array antenna and one single-feed multi-beam switchable array antenna. The proposed antenna contains three and four microstrip square patch antenna elements and a switchable feed network respectively. In dual-beam design, the feed network creates a 900 phase difference between the center element and the right or left antenna elements. This antenna can tilt its main beam direction to θ = by exciting either right or left antenna elements along with the center patch through two PIN diodes, respectively. The dual-beam switching concept is experimentally verified with better than 8 dBi gain for every condition at ɸ = 00-plane. The proposed multi-beam array antenna has two 900 switchable phase shifters. The 900 switchable phase shifter consists of a single-pole double-throw (SPDT) switch and a hybrid coupler. The hybrid coupler generates a 900 phase difference between the antenna elements to tilt its radiation pattern. The two SPDT switches can generate three modes to control the input ports of the hybrid coupler. As a result, two tilted beams and one difference pattern are generated from the same structure. A prototype multi-beam antenna is fabricated to demonstrate the concept experimentally. The measured results confirm the concept with a good agreement between the simulation and measurement. Better than 20dB cross-polarization suppression is achieved in the measurement. Description: An M.Sc. Thesis from the Department of Electronics and Telecommunication Engineering 2023-10-10T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/492 Title: An Integration of Planar Cavity-Backed Antenna with Artificial Magnetic Conductor in the Application of 2.4 GHz WBAN Application Authors: Murshed, Abu Hena Abstract: A high-gain array antenna is proposed using cavity-backed technology with the help of Substrate Integrated Waveguide Technology. The joint combination of both patch and the cavity-backed antenna is also known as a hybrid combination. Such types of antennas allow bandwidth enhancement and further division of patches to allow high gain and low cross-polarization behaviour. The whole patch antenna is further divided and based on the number of array elements in the patch, four array antenna cases have been proposed. A comprehensive investigation of them is presented. The proposed antenna operates at Ku-band, showing linearly polarized wave in TE101 mode and this hybrid combination provides several advantages. First, it has the advantages of a cavity-backed antenna and the conventional slot antenna. Second, an antenna is more compact. Third, it contains a much simpler matching network. In addition, being a member of the planner waveguide family, the proposed antenna also possesses a low profile and allows easy integration with the planner circuit. An exact representation of parameters of all antennas that have emerged during the designing course helps to grasp the sense of designing such kinds of hybrid array antenna of planner waveguide technology. Later, the proposed antenna is verified experimentally and exhibits a satisfying agreement with the data found during numerical simulation. The antennae’s simulated parameters were investigated with the help of CST (computer simulation technology) and HFSS (high frequency structure simulator) simulation software in microwave momentum mode. Description: An M.Sc. Thesis from the Department of Electronics & Telecommunication Engineering 2023-11-02T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/487 Title: Analysis on simple feed microstrip patch array antenna design for circular polarization diversity and beam switching with DOA estimation. Authors: Das, Debprosad Abstract: The terminal node antenna of a wireless communication device should possess the ability to perform many roles since modern communication necessitates the adoption of advanced approaches to address the rapidly evolving needs of end users. Circular polarization diversity, beam switching, and direction-of-arrival estimation (DOA) are advanced antenna applications that can enhance power efficiency and enable lossless transmission, therefore addressing the demands of the present time. In addition, it is necessary for the devices, especially the antennas, to have lower dimensions, even when considering long-distance communication, which typically requires a large-scale array antenna. Integrating microstrip patch antennas, which have a low profile and are lightweight, into transmitting or receiving devices can resolve the problem. This thesis study focuses on the design and simulation of a microstrip patch array antenna. The purpose is to analyze its applicability in the areas of circular polarization, beam-switching, and DOA estimation. A microstrip patch array antenna is constructed using both-sided microwave integrated circuit (MIC) technology to achieve circular polarization while keeping the feed network simple. A four-element microstrip patch array antenna is constructed, simulated, and validated to determine the feasibility of creating a large extensible array with 256 elements. The antenna utilizes a simple single feed to achieve circular polarization. By making a simple adjustment to the feed line, the formation of a Magic-T junction enables beam switching. Additionally, a simple modification in the design allows for direction of arrival (DOA) estimation. The simulation results demonstrate that the antennas have the capacity to transmit across long distances with circular polarization, achieving a gain of more than 26.15 dBic. Additionally, the antennas can alter their beam direction by up to ±17◦. Additionally, they have the capability to determine position by isolating the sum signal and the difference signal by different ports. Keywords: Array antenna, Beam switching, Both-sided MIC, Circular polarization, DOA estimation, Left-hand circular polarization (LHCP), Magic-T, Microstrip patch, Right-hand circular polarization (RHCP). Description: Thesis for Master of Science in ETE 2024-05-21T00:00:00Z