AOS/C²OMODO: INNOVATIVE RADIOMETER SUBASSEMBLIES DESCRIPTION AND TEST RESULTS

J. Puech¹, X. Boulanger², L. Hermozo², R. Redondo², N. Steunou¹, T. Amiot², H. Brogniez³, R. Rocca⁴, J. Chaboureau⁵, F. Auguste⁵, D. Bouniol⁶, T. Fiolleau⁴, J. Delanoe³, J. Tourbot⁷, D. Sanson⁷, L. Costes⁷, C. Tucker⁸, P. Ade⁸, I. Walker⁸, J. Treuttel⁹, G. Gay⁹, L. Gatilova⁹, A. Feret⁹, T. Vacelet⁹, J. Krieg⁹, M. Brandt¹⁰, M. Trasatti¹⁰

¹Centre National d’Etudes Spatiales (CNES), ²CNES, ³LATMOS, ⁴LEGOS, ⁵LAERO, ⁶CNRM, Météo-France, ⁷Airbus Defence and Space, ⁸Cardiff University, ⁹LIRA, ¹⁰RPG

In a first part, the C²OMODO (Convective Core Observations through MicrOwave Derivatives in the trOpics) observation system will be presented. CNES will provide a tandem of two multispectral, high-resolution all-sky atmospheric microwave radiometers. They will fly on-board the two satellites following the same ground track on the AOS inclined orbit and separated by about 1 minute. In a second part, the microwave radiometer will be discussed. The third part will focus on three critical sub-systems that require an increase in their Technology Readiness Level (TRL): the quasi-optical network of the antenna sub-system and the Front-End at 325 GHz and the Front-End at 183 GHz. The Quasi-optical network (QON) enables co-location and co-registration of the measurements at the different frequencies. Its primary functions include feeding the 3 different receivers, generating the 3 radiation patterns, while fitting in a constrained instrumental volume. A design study led by Cardiff University and Airbus DS has enabled to define the architecture of the entire QON assembly. Breadboard measurements confirm the RF performances of the assembly, demonstrating very low insertion losses at each frequency: a key parameter for success. As for the co-localization, a figure demonstrating the co- measured performances with the measurement of the centroids will illustrate the results. Downstream, the Front-End at 325 GHz and at 183 GHz convert the RF signal into the intermediate frequency (IF). A high performance 325 GHz mixer has been designed by the LIRA laboratory with three different topologies evaluated and compared. Pre-developments to reach TRL6 were also conducted by RPG to develop a high performance 183 GHz Front-End. The performances at ambient, cold and hot temperatures of the 183 GHz Front-End are summarized will be presented.