logic of coupling between two types of antennas

[yefj]

Hello , in the attached article there is a contradiction i cant understand.
On one hand they say that on the high frequency patches we have 1.8 Lambda distance array.
What distance did they play width to suppress the grating lobes at 34?
Thanks.

 

[yefj]

Hello, in the attached article they have a certain element shown bellow where its zeros is being planned to fit the grating lobes of the array factor.
What is the name of this anntena?
How do we plan the zero location of such antenna?
As shown bellow from the article they used pairs to plan the zeros,how exactly it could be?
Thanks.

 

[yefj]

Hello ,In the attached article i got two types of antennas.
one on low frequency and the other in high frequency as shown bellow.
We have two types of antennas together ,one antenna(high frequency) radiates at horisontal polarization and the other(low frequency) with vertical polarization.
In the article they say that mutual coupling is contolled by orthogonal orientation.
I dont understand that ,why the difference in polarization cancelles the effect of low frequency antenna will ruin the S11 of the high frequency antenna?
Its a foreign object ,it will do coupling and create returns.