Looking into the emerging applications of tin oxide thin films in the microwave frequency range, this paper reports the properties of tin oxide thin films of different thicknesses (103-496 nm) on alumina substrate. The tin oxide thin films were prepared by thermal oxidation (in air) of vacuum evaporated tin thin films. Surface morphology showed spherical shaped particles of tin oxide. The surface roughness was found to increase with increase in oxidation temperatures. As the oxidation temperature increases the tin oxide thin films show change from hydrophobic to hydrophilic nature. Electrical and microwave properties of tin oxide for different oxidation temperature were carried out. Microwave absorption were found to decrease with increase in oxidation temperature. Frequency and oxidation temperature dependent microwave permittivity was observed. The dielectric constant varied in the range 1.6 and 2.38.
