Huang, FrederickFrederickHuangBOLLI, PietroPietroBOLLICRESCI, LucaLucaCRESCIMARIOTTI, SERGIOSERGIOMARIOTTIPANELLA, DarioDarioPANELLALopez-Perez, Jose A.Jose A.Lopez-PerezGarcia, PabloPabloGarcia2021-01-042021-01-0420181751-8725http://hdl.handle.net/20.500.12386/29435An iterative technique to adjust ripple in a bandpass filter has been developed by curve-fitting numerical data. It gives an approximate relation of ripple against filter coupling coefficients and resonator resonant frequencies instead of finding a Jacobian matrix for each individual filter, in exchange for making more iterations. Numerical examples show reasonable convergence for Chebyshev filters up to the 16th-order, coupled quadruplets, coupled triplets and folded cross-coupled filters. A bandpass filter for a radio telescope in Yebes, Spain is designed and measured, a tenth-order superconducting spiral filter with 7% bandwidth, 2295 MHz centre frequency, <0.1 dB ripple and overall substrate size 30 mm × 8 mm. The 11 iterative simulations totalled 8.5 h of computer processing time.STAMPAenArticle10.1049/iet-map.2017.09402-s2.0-85048363820000434991400008https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/iet-map.2017.0940FIS/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