| Description: | As part of the Anglo-Dutch collaboration during the eighties of the previous century, ASTRON contributed to the mm/sub-mm James Clark Maxwell Telescope on top of Mauna Kea on the Big Island of Hawaii. One of our contributions was a 350 GHz receiver, for which cryogenic Schottky diode mixers were developped. The pictures show the result of this development with a drawing of the 350 GHz waveguide mixer and the mixer assembly for mounting in a 20 K closed cycle refrigerator. The mixer and assembly were manufactured in ASTRON's mechanical workshop and involved micro machining on a lathe of the small waveguide and RF/IF circuit parts, as well as electroforming of the input rectangular waveguide horn. Notice the small dimensions of the waveguide and RF/IF circuit in the detail of the drawing. LO- and RF-signals were coupled into the waveguide horn using quasi-optical techniques, with a lense also serving as a vacuum window in the cryostat.
One of the pictures shows an experimental setup of a mixer mounted to the 20 K station of a CTI model 21 cryocooler. |
