Development of the 787–950 GHz ALMA Band 10 cartridge

We are developing the Atacama large millimeter/submillimeter array (ALMA) band 10 (787-950 GHz) receiver cartridge. The double-side-band (DSB) mixer consists of a corrugated feed horn, a full-height waveguide mixer block and a Nb(Ti)N-based superconductor-insulator-superconductor (SIS) mixer chip. The IF system uses a 4-12-GHz cooled low-noise InP-based MMIC amplifier and a 4-12-GHz isolator. Heterodyne sensitivity tests showed the mixer noise temperature of about 200 K in the 800 GHz band at an operating temperature of 4 K. This result is comparable to the state-of-the-art mixer performance at this frequency range.