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enter image description hereI have an 2D array of 64 antenna element. Lets say each antenna is connected to one RF chain. with this array total 64 parallel data streams can be transmitted with some pre-processing. When the load on the system is low (need to support less streams), we can mute some of the RF chains (PAs) to save power.

But muting the antenna/RF chain will affect the effective aperture/ array factor/aperture size of the antenna.

What is the best way to mute so that we have little impact on the antenna aperture?

Lets say the 2D array is 8 X 8

Since the aperture depends on the physical size of the place over which the antenna elements are arranged, what is an optimal ay to mute the antenna. Lets say we want to mute half of the antennas.

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  • \$\begingroup\$ From what i can remember from my uni years, muting elements from array antenna will effect the beam shape. If you can live with that then muting far end elements will change the beam shape but will maintain the range. As to your actual question on how to mute the elements, since you mentioned each element has its own stream, I'd assume you also have transmetter with individual connection so it should be easy to enable/disable them individually. \$\endgroup\$
    – Prashant
    Commented Oct 2, 2023 at 10:59

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These comments assume we're talking about an active ESA, with a receive and transmit path behind each individual element.

If you mute (turn off) elements randomly scattered across the aperture, as opposed to turning off end elements, you will preserve your aperture size. Doing so will, however, affect your beam pattern with sidelobes coming and going across the scan region.

It's hard to predict exactly what the pattern does. You have to model/simulate the array with a given set of active elements across the scan region to see what the pattern does.

Note that turning off edge elements in an array is sometimes used when it is desired to fatten, or broaden the width of your main beam. But you take a gain hit (reduction) on receive and an EIRP hit on transmit when you do this, because 1) the aperture is smaller and 2) you have less elements being used.

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  • \$\begingroup\$ Thanks for you answer. For now we can ignore the receive path (for example, we can keep all the receive paths unmuted/ON). Yes we have an EIRP hit on transmit. Somewhere I learned that the array factor depends only on the physical size of the antenna array. hat happens if we try to keep (most of the elements) the edge elements ON while muting the inside elements? \$\endgroup\$
    – MGM
    Commented Oct 2, 2023 at 14:06
  • \$\begingroup\$ Your beam pattern changes. Now it looks like two arrays, separated by some distance greater than half a wavelength, which means you may see grating lobes appear in real space. \$\endgroup\$
    – SteveSh
    Commented Oct 2, 2023 at 14:52
  • \$\begingroup\$ what do you mean by Now it looks like two arrays, separated by some distance greater than half a wavelength? \$\endgroup\$
    – MGM
    Commented Oct 3, 2023 at 8:09
  • \$\begingroup\$ Because the OFF elements in the center the array puts a hole in your array. If we take your 8x8 array, assume that the array elements are space lamda/2 apart, and turn of the middle two columns (4 & 5), then the left half and right half the array are separated by 1.5*lamda. \$\endgroup\$
    – SteveSh
    Commented Oct 3, 2023 at 13:13
  • \$\begingroup\$ thanks a lot for your answer. I have attached an image to the post. Would you comment on the array factor and other antenna features due to muting of antenna elements. What is the best way to maximise the aperture while muting some of the antenna elements. \$\endgroup\$
    – MGM
    Commented Oct 4, 2023 at 19:55

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