Alumina thick films as integral substrates using aerosol deposition method

Alumina thick films were fabricated by the aerosol deposition method (ADM) as integral substrates for integrated RF modules. By selecting a suitable powder and deposition conditions, alumina thick films as an integral substrate were successfully grown on glass and Al substrates at room temperature by the ADM. The relative dielectric permittivity and loss tangent of the alumina thick films on Al substrates were 9.5 and 0.005, respectively. To form microstrip lines on the aerosol-deposited alumina thick films, copper electroplating and lithography were employed, and a square-type cross section with sharp edges was obtained. Low-pass LC filters with a cutoff frequency of 10 GHz were simulated by electromagnetic analysis. The possibility of miniaturization of RF modules is proposed using alumina thick films fabricated by the ADM as an integral substrate.