Tin-oxide/iron-oxide and yttrium-iron-oxide thin-films have been produced with the sol-gel method. Film thicknesses from 50 to 155 nm were deposited by the sol-to-gel transformation onto borosilicate substrates. The dielectric losses of the films were deduced by the complex reflection coefficient of these materials in the range from 2 GHz to 18GHz using an HP network analyzer.

Samples of 5 cm × 5 cm were centered on the waveguide flange and a shorting plate (12.2 cm × 15.2 cm) of brass centered over the sample. Measurements were automatically made using the HP software provided.

In the X-Band region, three absorption bands at 8.3, 9.4, and 11.5 GHz were detected for the substrate, with losses (absorption peaks) ranging from 13.5, 11.9, and 9.9, respectively. For the tin-oxide/iron-oxide sol-gel coated substrate, three bands at 8.4, 9.5, and 11.6 GHz were observed having losses of 16.2 to 13.4, 12.9 to 11.4. and 11.3 to 9.7, respectively, depending upon thickness and orientation. For the yttrium-iron-oxide sol-gel coated substrate, three bands at 8.4, 9.5, and 11.6, with losses depending upon solgel thickness and orientation.