Ultra-wide IF bandwidth — The next frontier for SIS receivers

Tucker´s theory of quantum mixing can be extended to model distributed series connected SIS mixers, which offer a lower capacitance and a higher dynamic range. These mixers have wider IF bandwidth than single junction mixer. Coupled with the emerging ultra-wide band technologies in low noise amplifier and fast digital signal processing, they open a new frontier of ultra-wide band receivers. We report on the development of the wideband SIS receivers for the Submillimeter Array, designed with Tucker´s theory.