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Nicole's Project Page |
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Intern: Nicole Lemaster, UCSB
Mentor: Miikkas Kangas
Faculty Supervisor: Dr. Phil Lubin
Department: Physics |
CORRUGATED 90-GHZ PLATELET HORN ARRAY
Feedhorns direct energy from free space onto our detectors. Corrugated horns have tighter beam patterns, reduced sidelobes, and lower losses and polarization crosstalk than smooth-walled horns, but are harder to fabricate because of the need for more difficult machining and electroforming processes. Corrugated horns can also be manufactured in platelet arrays, with tilts built into the horns by offsetting the plate layers. It is possible to manufacture arrays of horns inexpensively by machining the plates individually and stacking them together. No diffusion bonding or gold plating has been necessary to achieve performance comparable to electroformed gold-plated silver corrugated horns from unplated cartridge brass shim stock and sheet metal. These tilted platelet horns have unusual beam patterns where the exit main lobe angle is empirically about 5/8ths of the tilt of the platelet horn with an 8 degree tilt in the platelet horn. The sidelobes are also affected a bit, with the secondary lobes moving in unison with resect to the main lobe and the one that moves closer to the main lobe being amplified and the one moving away from the main lobe being suppressed. This is in the coordinate frame of the main lobe. This may be important to experiments attempting to measure polarized signals like CMB polarization experiments.
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