We are developing monolithic arrays of corrugated feed horns fabricated in silicon for dual-polarization single mode operation at 90, 145 and 220 GHz. The arrays consist of hundreds of platelet feed horns assembled from gold coated stacks of micromachined silicon wafers. As a first step, Au coated Si waveguides with a circular, corrugated cross section were fabricated; their attenuation was measured to be <0.15 from dB/cm 80 to 110 GHz at room temperature. To ease the manufacture of horn arrays, electrolytic deposition of Au on degenerate Si without a metal seed layer was demonstrated. An apparatus for measuring the radiation pattern, optical efficiency, and spectral band pass of prototype horns is described. Feed horn arrays made of silicon may find use in polarization anisotropy measurements of the cosmic microwave background radiation.
Proceedings Title: unknown
Conference Dates: July 20-24, 2009
Conference Location: Palo Alto, CA
Conference Title: Low Temperature Devices 13
Pub Type: Conferences
mm-wave optics, cryoelectronics, experimental cosmology, optics