Nurulfadzilah Binti Hasan creator author. text my 2025 2025 monographic eng xvii, 150 pages : illustrations ; 30 cm. + 1 CD-ROM Composite materials are created by blending base substances like polymers and epoxy resin with fillers such as ceramic powders, carbon fibres, and carbon nanotubes. The permittivity of these composites can be adjusted by varying the filler concentration. With the growing need for compact wireless communication systems, there is increasing demand for miniaturized antenna. A highly effective method to achieve this is by using high-permittivity composite dielectrics as antenna substrates. This technique not only minimize the antenna structure but also preserves the original shape of the antenna. Thus, this research focuses on the formulation of a novel high permittivity epoxy-barium titanate composite (epoxy-BT) has been developed by using mechanical mixing and in-situ polymerization processes. Four different types of epoxy-barium titanate composites have been formulated, each with different filler volume ratio of barium titanate filler (10%, 20%, 30% and 40% vol.). Then mechanical and electrical characteristics of the composite are determined through a series of tests. The test results in laboratory experiments shows that the permittivity of the composites increases almost linearly with the volume of barium titanate, with the highest permittivity achieved is 16.11 for epoxy-BT composite with 40 %vol. filler concentration. Tests results also shows that the composite's mechanical characteristics are comparable to those of epoxy. Thus, this composite is suitable to be used as dielectric substrate for microstrip antenna. In the second part of this research, rectangular microstrip antenna with epoxy-barium titanate composite substrate was design and modelled in CST Studio Suite 2020 simulation software. The results demostrated that microstrip antennas with an epoxy-BT composite substrate has good performance compared to antenna with FR-4 substrates. Additionally, the size of the antennas with epoxy-BT composite substrates are significantly smaller than conventional antennas with up to 70% size reduction achieved. Thus, the proposed epoxy-BT composite is a suitable dielectric material for miniaturized microstrip patch antenna. Finally, the antennas with epoxy-BT substrate were fabricated and their performance were tested. The results of both simulation and measurements a high correlation, thus validating the outcomes. specialized Nurulfadzilah Binti Hasan Faculty of Electrical and Electronics Engineering Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2025 Includes bibliographical references Faculty of Electrical and Electronics Engineering Dissertations Universities and colleges Dissertations Theses Dissertations THE0010153 (Local) UMPSA 251211 20251217160047.0 eng