Cameras in the millimeter range

In recent years laboratories worldwide are focusing their efforts on developing heterodyne cameras in different frequency ranges. The main reason is that array instruments can increase dramatically the mapping efficiency of current telescopes. The Millimeter-wave Laboratory (MWL) have focused its work on W-band heterodyne receivers covering three areas of study:

(a) Development of optical systems for cameras: The design is intended for a 12-m class antenna, because an important potential interest of this study is the use of multi-pixel receivers in ALMA antennas. Therefore we designed a circular array of receivers with 7 pixels (extensible to 19 pixels) that fits into an ALMA style receiver cartridge.

(b) Compact feeds and orthomode transducers: This work relays on the developments associated with the ALMA Band 2+3 project. For the feed, we use smooth-wall horns to allow a compact array that fits in the available space. The possibility of using planar antennas is also considered. To take full advantage of the capabilities of a focal plane array, a double polarization scheme is desirable, so the MWL designed circular horns and OMTs to separate the two polarizations.

(c) Active components for W-Band: The MWL is developing sub-harmonic mixers based on Schottky diodes to be used as down-converters in this system, as well as power amplifiers at 60 GHz based on MMIC technology. This amplifiers are envisioned as key component of the LO routing scheme of a W-band array.