AUTOMATED MICROWAVE MEASUREMENTS OF MICROSTRIP RING RESONATORS AT LOW-TEMPERATURES

The high frequency properties of both subserates and superconducting m aterials have been determined from relatively large area microstrip re sonator circuits mounted in an automated measurement system. Propertie s such as dielectric constant and surface resistance are presented for a variety of materials, such as YBa2Cu3O7-x, Tl2Ba2Ca2Cu3Ox, eu and A g on either yttria-stabilised zirconia, MgO or plastic substrates, The surface resistance of thick film YBa2Cu3O7-x ring resonators on yttri a-stabilised zirconia substrates were found tea be limited by the loss tangent of the substrate while the surface resistance of similarly-si zed Tl2Ba2Ca2Cu3Ox, thin film king resonators ore MgO substrates showe d a marked power dependence, At 3GHz the surface resistance of thick. film YBa2Cm3O7-x, on yttria-stabilised zirconia at -10dBm was found to be superior to thin film Tl2Ba2Ca2Cu3Ox on MgO below T-C/2 as a resul t of better power handling.