Nondestructive evaluation of the dielectric properties of the substrate materials for high-Tc superconducting microwave devices
Abstract:In this paper, microwave near-field scanning technique has been employed to study the local dielectric properties of the substrate materials for superconducting microwave devices. A coaxial cavity together with a niobium tip has been used as a probe in our scanning microwave near-field microscope (SMNFM). Using the SMNFM, quantitative measurement of both the relative permittivity and the loss tangent of various substrate materials for the high-temperature superconducting thin films have been obtained, which coincide with the data reported in the literature quite well. Nondestructive imaging of the dielectric properties of the substrate is also given with a spatial resolution of several micrometres. We believe that the SMNFM is a reliable method for nondestructively evaluating the dielectric properties of the substrates in the microwave circuit devices. It will be helpful to better understand the influences of the variations and defects in the substrates on the designing and performance of the superconducting microwave devices.
Document Type: Miscellaneous
Publication date: March 1, 2002