In this paper an additive manufactured (AM) W-band monolithic feed chain is presented. The feed chain, which consists of a corrugated horn antenna and a turnstile orthomode transducer (OMT), operates over the entire W-band (75-110 GHz) and fulfills typical RF specifications for a chosen space-borne radiometer application (RL > 20 dB, IL < 1 dB and Xpol < -30 dB). Both the OMT and the horn have been designed by exploiting the design freedom offered by AM, but also taking into account its specific technological constraints. The presented W-band design can be straightforwardly scaled to V-band.