Tapia, V.V.TapiaNESTI, RenzoRenzoNESTIGonzález, A.A.GonzálezBarrueto, I.I.BarruetoMena, F. P.F. P.MenaReyes, N.N.ReyesVILLA, FABRIZIOFABRIZIOVILLACUTTAIA, FRANCESCOFRANCESCOCUTTAIAYagoubov, P.P.Yagoubov2020-05-052020-05-05201697815106020760277-786Xhttp://hdl.handle.net/20.500.12386/24515ALMA is the largest radio astronomical facility in the world providing high sensitivity between 35 and 950 GHz, divided in 10 bands with fractional bandwidths between 19 and 36%. Having a lifespan of at least 30 years, ALMA carries out a permanent upgrading plan which, for the receivers, is focused on achieving better sensitivity and larger bandwidths. As result, an international consortium works on demonstrating a prototype receiver covering currents Bands 2 and 3 (67 to 116 GHz) which corresponds to a fractional bandwidth of 54%. Here we present the preliminary design, implementation and characterization of suitable refractive optics. Results indicate an excellent performance in good agreement with simulations.STAMPAenConference paper10.1117/12.22331432-s2.0-85009898372000385793800073http://dx.doi.org/10.1117/12.22331432016SPIE.9914E..2XTFIS/05 - ASTRONOMIA E ASTROFISICAScienze Fisiche Settori ERC (ERC) di riferimento::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