The Integration of LNA Based Receivers for Millimetre and Sub-millimetre Wavelength Radio Astronomy

With the recent developments of transistor technologies, Low Noise Amplifiers (LNAs) operating in the millimetre and sub-millimetre wave are now realisable with performance comparable to SIS junctions. This in turn allows for LNA based receiver instrumentation in these frequency ranges, such as the ESO ALMA Band 2 receiver (67-116GHz). The Millimetre-wave Technology group and the Technology Department at the STFC Rutherford Appleton Laboratory and the Advanced Radio Instrumentation Group at the University of Manchester have recently completed the sixteen-pixel, 70-116GHz Cryogenic Array Receiver for Users of the Sardinia Observatory (CARUSO) project. To achieve an appropriate spatial sampling of celestial sources the feedhorns of the receiver pixels were required to be tightly grouped together, limiting the available volume for the receiver components. This space limitation pushed the physical design of the individual components to the limits of what is achievable without further miniaturisation and integration of the receiver sub-components. Based on the success of the CARUSO receiver we have now embarked on TASER, a project funded by the ESO European ALMA Development Fund and the EU funded RADIOBLOCKS project. In this talk we will present the first steps toward highly integrated systems that will be able to provide a new generation of compact, highly sensitive, broad band receivers including, eventually, focal plane array systems for ALMA as well as other telescopes.