Power of main lob as depending on d = L/ג in linear antenna array

Hi
if i look at the main lob of for i.e. of two element without grating lobs i.e.(d=ג/2) and compare the power to d=ג
will i see change in the main lob measured power
i mean to ask does the grating lobs take power from the main lob?
why i want to remove them only to have a larger scanning angle?

<a title="power of array.JPG" href="../imgqa/eboard/Antenna/rf-3ma20ukdwrx.jpg"><img src="../imgqa/eboard/Antenna/rf-3ma20ukdwrx.jpg" alt="power of array.JPG" /></a>
http://obrazki.elektroda.pl/5267253400_1473949444.jpg