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|| $ D = \lambda/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 ) ) $ || ||<:-3> $ D = \lambda/2 $ ||<:-3> $ k = 2 \pi / N * L $ ||
|| $ \Delta x = D * ( \sin( k z ) + \cos( k y ) ) $ || ||<-2> $ \Delta y = D * ( \sin( k x ) + \cos( k z ) ) $ || || $ \Delta z = D * ( \sin( k y ) + \cos( k x ) ) $ ||
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We can scale D and k, and also modify amplitudes across the array like a Hamming window, and see how that changes the sidelobes. Try scaling D and k, and also modifying amplitudes across the array like a Hamming window, and see how that changes the sidelobes.

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 = \lambda/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. 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.

MORE LATER

ArrayPhasing (last edited 2021-06-08 17:57:55 by KeithLofstrom)