A BROAD BAND 230 GHZ ANTIPODAL FINLINE MIXER FOR ARRAY RECEIVERS

Finline transmission lines are easy to manufacture and to integrate with other planar components, but they have not, to our knowledge, been used for submillimetre SIS mixers. One of the main problems is the high characteristic impedance of these structures. In this paper we describe a design which overcomes this difficulty by including an antipodal fmline section with overlapping fins on either side of a dielectric layer deposited on a thick quartz substrate. We have designed and tested an antipodal finline mixer with fully integrated tuning. Preliminary results confirm our predictions that the finline structure is suitable for making low noise and easy to manufacture SIS mixers, and hence is suitable for large-format imaging arrays.