Design, implementation, and testing of the Microwave Anisotropy Probe radiometers

The Microwave Anisotropy Probe ( MAP) satellite, launched 2001 June 30, will produce full sky maps of the cosmic microwave background radiation in five frequency bands spanning 20-106 GHz. MAP contains 20 differential radiometers built with High Electron Mobility Transistor (HEMT) amplifiers with passively cooled input stages. The design and test techniques used to evaluate and minimize systematic errors and the prelaunch performance of the radiometers for all five bands are presented.