MILLIMETER WAVE
INSTRUMENTATION LAB


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Last Modified: Wednesday, 17-October-02 10:05 AM EDT




This material is based on work supported by the National Science Foundation under Grants AST-9532046 and AST-9725951.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect those of the National Science Foundation.

System Description continued...

  • SEQUOIA is intended as a relatively low cost system. Each pixel uses simple machining and low-cost components.
  • The second set of 16 pixels in the opposite polarization has been installed, using a wire grid for combination. The complete 32-pixel array is currently in use on the 14m FCRAO telescope.
  • The receiver is designed for remote use, and all functions may be accessed from anywhere in the world.


One of the SEQUOIA dewars with all 16 pixels installed. The lens/feed horns are located on the outside wall of the right-hand side of the dewar. The LO module is located outside the bottom wall.



Local Oscillator System


Local oscillator block diagram

  • LO provided by a 10.05 GHz DRO source which is multiplied and subsequently amplified to produce the 40.2 and 60.3 GHz frequencies.
  • LO distribution is one of the most difficult problems with array receivers.
  • LO is split 32 ways using magic-T waveguide splitters. Junctions are tuned for only 40GHz and 60GHz.

Some components of the LO system


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