Broadband NbTiN based SIS mixers for HIFI Band 2

We present SIS waveguide mixer results in the frequency range 638-802 GHz at an IF frequency of 4-8 GHz. We use Nb/Al/sub 2/O/sub 3//Nb junctions with areas down to 0.6 /spl mu/m/sup 2/ defined by e-beam lithography and chemical mechanical polishing (CMP), embedded in low loss NbTiN/SiO/sub 2//Nb or NbTiN/SiO/sub 2//Al microstrip tuning circuits.