Array receiver development at KOSMA for the submillimeter and terahertz spectral range

We describe frontend concepts for the future heterodyne array instruments of the KOSMA 3-m telescope and for SOFIA. For KOSMA we are currently developing a dual frequency (400 - 500, 800 - 900 GHz) SIS mixer array of four elements per frequency band. For SOFIA, we are planning an up to 4 X 4 element array for 1.6 - 2.0 THz using superconducting hot-electron bolometers. The small number of pixels allows us to keep the optics relatively compact. For the same reason, a single sideband filter is not included. The local oscillator power will be distributed using Dammann gratings. Motivated by the excellent beam characteristics of waveguide horns we are planning to extend the range of our waveguide mixers to 2 THz. The mixers are based on the wideband tunerless mixers that have been successfully used in single element telescope receivers at KOSMA. The mixers will be standard building blocks mounted at the back of waveguide horns integrated into the optical setup. Local oscillators for 400 - 900 GHz are solid state sources, for the Terahertz array we are developing several alternative local oscillator concepts.