Peter Napier [1]
May 4, 1994
Keywords: antennas, off-axis antenna, polarization
The offset geometry of the Open Cassegrain antenna design proposed for the MMA will cause circularly polarized beams to be separated by 0.14 beamwidths, compared with a separation of 0.06 beamwidths for the VLA. If uncorrected this circular polarization beam squint will seriously limit the ability of the MMA to measure circular polarization. Two methods are proposed to correct this polarization degradation. Both of these solutions require the addition of reflectprs in the optical path and need further study to be sure that ther are no undesired diffraction effects in the longest MMA wavelength bands.
View a PDF version of MMA Memo #115.
Download a PS version of MMA Memo #115.
Last modified: 09 December, 1999
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