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Film-thickness dependence of 10 GHz Nb coplanar-waveguide resonators.
- Source :
- Journal of Vacuum Science & Technology: Part B-Microelectronics & Nanometer Structures; Sep2009, Vol. 27 Issue 5, p2286-2291, 6p, 3 Diagrams, 3 Charts, 5 Graphs
- Publication Year :
- 2009
-
Abstract
- The authors have studied Nb λ/2 coplanar-waveguide (CPW) resonators whose resonant frequencies are 10–11 GHz. The resonators have different film thicknesses, t=0.05, 0.1, 0.2, and 0.3 μm. They measured at low temperatures, T=0.02–5 K, one of the scattering-matrix element, S<subscript>21</subscript>, which is the transmission coefficient from one port to the other. At the base temperatures, T=0.02–0.03 K, the resonators are overcoupled to the input/output microwave lines, and the loaded quality factors are on the order of 10<superscript>3</superscript>. The resonant frequency has a considerably larger film-thickness dependence compared to the predictions by circuit simulators which calculate the inductance of CPW taking into account L<subscript>g</subscript> only, where L<subscript>g</subscript> is the usual magnetic inductance determined by the CPW geometry. By fitting a theoretical S<subscript>21</subscript> versus frequency curve to the experimental data, they determined for each film thickness the phase velocity of the CPW with an accuracy better than 0.1%. The large film-thickness dependence must be due to the kinetic inductance L<subscript>k</subscript> of the CPW center conductor. They also measured S<subscript>21</subscript> as a function of temperature up to T=4–5 K, and confirmed that both thickness and temperature dependence are consistent with the theoretical prediction for L<subscript>k</subscript>. [ABSTRACT FROM AUTHOR]
- Subjects :
- WAVEGUIDES
THICK films
ELECTRODYNAMICS
LOW temperatures
FREQUENCY curves
Subjects
Details
- Language :
- English
- ISSN :
- 10711023
- Volume :
- 27
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- Journal of Vacuum Science & Technology: Part B-Microelectronics & Nanometer Structures
- Publication Type :
- Academic Journal
- Accession number :
- 44449805
- Full Text :
- https://doi.org/10.1116/1.3232301