Initial Concept and Roadmap of the Band-4+5 Receiver Upgrade of the Atacama Large Millimeter / Submillimeter Array (ALMA)

The Band-4+5 receivers of the Atacama Large Millimeter / Submillimeter Array (ALMA) is proposed for the upgrade after 2030. The new receiver will cover the RF frequency of the original Band-4 (125 – 163 GHz) and Band-5 (163 -211 GHz) with continuous frequency tuning over dual polarizations, dual sidebands with instantaneous intermediate frequency (IF) bandwidth up to 16 GHz per sideband and per polarization.