how to understand grating lobe problem in broadside array

Thread Starter

yef smith

Joined Aug 2, 2020
289
Hello,In a broad side array we have a radiation pattern which Array factor development shown bellow.
I can understand what is the problem that is called "grating lobe"
We bellow have th Array paatern expression howcan i see the grating lobe problem from it?
In the last photo we have an expression but i cant see the intuition of how to get it?
Thanks.

1617122763442.png

1617122794713.png
 

Delta Prime

Joined Nov 15, 2019
1,149
Hello there :) This looks like homework and I really like it here I can't give you the answer but can you give me your best attempt at solving it?
I'll give you a hint it's the process when used with the calculator chug and plug.
 

Thread Starter

yef smith

Joined Aug 2, 2020
289
i read its because of wrapping every 2pi ,but i could not imagine how large "d" makes this wrapping.
Is there some intuition you can help me with?
Thanks.
 

Thread Starter

yef smith

Joined Aug 2, 2020
289
Hello ,I have tried to implement the grating lobes into full mathematical example as shown in the photo bellow.

i understand that grating lobe happen when two elements get the same phase for example 10 and 10+360=370
could you please guide me ragarding how to update my example so i will see grating lobe with the main lobe?
Thanks.


111.jpeg
 
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