Integrated niobium thin film air bridges as variable capacitors for superconducting GHz electronic circuits

Superconducting GHz electronics can be improved by variable tuning circuits. We present a low temperature (<150/spl deg/C) process for the fabrication of niobium (Nb) thin film air bridges as variable capacitors, which can be integrated in Nb superconducting electronics. These elements can be applied for on-chip adjustment of filters, resonators and tuning circuits. Measurements and calculations of the electrostatic actuation of the bridges will be compared.