Hot electron bolometer waveguide mixers up to 4.7 THz for the upGREAT focal plane array receiver on SOFIA

We report on our waveguide hot electron bolometer (HEB) mixer development for the heterodyne focal plane array receiver upGREAT, which is the multi-pixel extension to the German Receiver for Astronomy at Terahertz frequencies (GREAT) currently in operation on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We will present results for our new generation of HEB mixers for operation at frequencies up to 4.7 THz reviewing the RF circuit design, device fabrication and waveguide technology.