Iron-oxide and yttrium-iron-oxide thin films: A test of the feasibility of producing and measuring micro- and millimeter-wave materials

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 18 GHz using an HP network analyzer. Samples of 5 cm x 5 cm were centered on the waveguide flange and a shorting plate (12.2 cm x 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