Differences between revisions 9 and 12 (spanning 3 versions)
 ⇤ ← Revision 9 as of 2012-11-30 06:44:38 → Size: 1065 Editor: KeithLofstrom Comment: ← Revision 12 as of 2012-12-05 13:38:01 → ⇥ Size: 1284 Editor: KeithLofstrom Comment: Deletions are marked like this. Additions are marked like this. Line 8: Line 8: ||<:-3> $D = \lambda/2$ ||<:-3> $k = 2 \pi / N * L$ || ||<:-3> $D = L/2$ ||<:-3> $k = 2 \pi / N * L$ || Line 11: Line 11: ... or some variation of that. This assumes the spacing $L >> \lambda$, a sparse array, so that the antennas do not couple (much). ... or some variation of that ( I originally tried $D = \lambda/2$ , with little effect). This assumes the spacing $L >> \lambda$, a sparse array, so that the antennas do not couple (much). Line 19: Line 19: There will probably be stiff competition for spacing functions, perhaps some trolls will take out patents on them, and in the current US patent climate, with

# Array Phasing

When we randomly dither the position of the emitters in a 3 dimensional phased array, it smears out the grating lobes. I am looking for a better function.

A position dither function to try:

 D = L/2 k = 2 \pi / N * L \Delta x = D * ( \sin( k z ) + \cos( k y ) ) \Delta y = D * ( \sin( k x ) + \cos( k z ) ) \Delta z = D * ( \sin( k y ) + \cos( k x ) )

... or some variation of that ( I originally tried D = \lambda/2 , with little effect). This assumes the spacing L >> \lambda , a sparse array, so that the antennas do not couple (much). Try scaling D and k, and also modifying amplitudes across the array like a Hamming window, and see how that changes the sidelobes.

This happens on top of the array of perhaps hundreds of emitters on the thinsat itself, which beamforms to a few degrees of angle, reducing power splattered far from the target.

The signal is broadband, so there is not a well defined \lambda . We may end up making k a function of x, y, and z as well.

There will probably be stiff competition for spacing functions, perhaps some trolls will take out patents on them, and in the current US patent climate, with

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ArrayPhasing (last edited 2022-03-15 01:37:15 by KeithLofstrom)