An integrated quasioptical receiver consisting of a planar double dipole antenna, superconductor‐insulator‐superconductor mixer and a superconducting local oscillator (LO) with matching circuits has been designed, fabricated and tested in the frequency range 360–490 GHz. A flux‐flow oscillator (FFO) based on unidirectional and viscous flow of magnetic vortexes in a long Josephsontunnel junction, is employed as a local oscillator. All components of the receiver are integrated on a 4 mm×4 mm×0.2 mm crystalline quartz substrate using a single Nb–AlO x –Nb trilayer. The lowest DSB noise temperature of 470–560 K has been achieved within a frequency range of 425–455 GHz.