Title :
Influence of buffer layers within YBa/sub 2/Cu/sub 3/O/sub 7-x/ coplanar waveguide structure
Author :
Kessler, John ; Dill, R.
Author_Institution :
Tech. Univ., Munchen, Germany
Abstract :
A YBa/sub 2/Cu/sub 3/O/sub 7-x/ coplanar waveguide structure is investigated theoretically via a partial wave synthesis. The high-T/sub c/ superconductor material is described by the two-fluid model and the London theory. A very thin buffer layer of about 100 nm thickness is positioned between the substrate and the superconducting film. The material combinations considered for buffer layer/substrate are: zirconium oxide/sapphire, strontium titanate/sapphire, zirconium oxide/silicon, and lanthanum aluminate/silicon. The influence of these buffer layers on effective permittivity and attenuation is examined over a wide range of structure widths whereby the attenuation is subdivided into superconductor losses, losses in the buffer layer, and substrate losses.<>
Keywords :
barium compounds; high-temperature superconductors; losses; permittivity; superconducting thin films; waveguides; yttrium compounds; Al/sub 2/O/sub 3/ substrate; CPW structure; LaAlO/sub 3/-Si; London theory; Si substrate; SrTiO/sub 2/-Al/sub 2/O/sub 3/; YBa/sub 2/Cu/sub 3/O/sub 7-x/; ZrO/sub 2/-Al/sub 2/O/sub 3/; ZrO/sub 2/-Si; attenuation; buffer layer losses; buffer layers; coplanar waveguide; effective permittivity; high-T/sub c/ superconductor material; partial wave synthesis; sapphire substrate; substrate losses; superconductor losses; two-fluid model; Attenuation; Buffer layers; Coplanar waveguides; Silicon; Substrates; Superconducting epitaxial layers; Superconducting films; Superconducting materials; Waveguide components; Zirconium;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
