Flexible antennas based on natural rubber / Norazlin Mohamad Razali

This thesis explores the use of natural rubber as a novel substrate in development of flexible antenna. Reinforcement agent known as filler was added into the rubber matrix to improve its mechanical properties. The type of filler used in this research is carbon black. Different types of rubber were produced by using a standard formulation but with different quantities of carbon black powder. Rubber laminates of different thickness and size were using hot compression technique which enabled it to mould the rubber according to the moulding plate. The study on the dielectric properties of rubbers with different filler loading were carried out. Dielectric measurements were conducted using microwave non-destructive testing and open ended waveguide methods. Results obtained from both techniques were in agreement with theories where it was found the dielectric permittivity and loss tangent increase with increased filler content. Thus the dielectric properties of the rubber were manipulated by only varying the filler content. Using the characterized rubbers from the study conducted, prototypes of simple topology microstrip antenna were fabricated and tested. The simulation and measurement of the antennas return loss and radiation pattern for three different cases were conducted and discussed thoroughly. Additional studies were also conducted regarding the effects of filler content and the effects of rubber thickness on antenna performance. Studies on the bending effects of antenna for three different conditions were also carried out. All results are validated and analysed to prove the feasibility of using natural rubber in development of flexible antenna.