Huang, FFHuangBOLLI, PietroPietroBOLLIMARIOTTI, SERGIOSERGIOMARIOTTI2022-02-072022-02-0720201751-8725http://hdl.handle.net/20.500.12386/31365The higher order resonances of microwave superconducting filters with spiral resonators were suppressed, giving a very wide stop-band. In one filter spirals were modified to have equal fundamental resonances, but different higher order resonances, by adding stubs and using non-uniform line width. The higher resonances were reduced to −39 dB, in a stop band up to 4.3 times the pass band centre. In another filter, parasitic resistive resonators were added, suppressing the responses to −57 dB. The resistance is provided by patterning the 200 nm gold overlay already required for the external contacts. The increase in pass band loss is not measurable. Measurements of a single spiral resonator with a gold-YBCO bi-layer (200 and 600 nm respectively) suggest that the resistivity of the gold layer at 15 K is the order of 22 times that of bulk gold, a slight advantage for the present application. At 100 K, it is about double.STAMPAenArticle10.1049/iet-map.2019.11132-s2.0-85096965454WOS:000595797900028https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/iet-map.2019.1113https://api.elsevier.com/content/abstract/scopus_id/85096965454FIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_17 Instrumentation – telescopes, detectors and techniques