Bi-layer kinetic inductance detectors for W-band

An array of superconducting kinetic inductance detectors (KID) has been fabricated and it has demonstrated absorption at W-Band. The use of a bi-layer structure based on aluminum (AI) and titanium (Ti) shows a lower superconducting critical temperature (T c ), which allows the detection at W-band. A design methodology is presented taking into account the KID geometry in order to maximize the absorption and a dual-polarization KID has been designed using the proposed methodology. Two prototypes of KID on Silicon substrate have been fabricated showing a good agreement between measurement and simulation results. The measurements at room temperature from 65 to 110 GHz show the matching at the frequency band, while dark cryogenic characterization demonstrated the low frequency design.The authors acknowledge financial supports: Ministry of Science, Innovation and Universities Grants ESP2017-83921-C2-2-R, ESP2017-86582-C4-1-R, ESP2017-86582-C4-3-R, MAT2017-85617-R, ESP2017-92706-EXP, AYA2017-92153-EXP and from Comunidad de Madrid through Grant P2018/NMT-4291 TEC2-SPACE-CM. A.G. acknowledges IJCI-2017-33991; IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686). D.G. and A.G also acknowledge Grant DEFROST N62909-19-1-2053 from ONR-Global