mutual coupling in (E,H) planes...

I have made a simulation of a network patch antenna (2-antennas) in both planes (E, H)

in E plane:
case 1: i simulate 2 patch antenna with (ep_r=10.2 and h(height)=1mm)

case 2: i simulate 2 patch antenna with (ep_r=10.2 and h(height)=4mm)

in two case distance between the two antennas is (lambda/2)...(fr=2.45GHz)

i obtain in case1: S_21=-15.91dB

case2: S_21=-15.61dB

question:
-although the difference between the two cases and 3mm in height of the substrate , but there is no great difference between the coefficient of mutual coupling

and in H plane i simulate 4 cases

1-case1:(ep_r=2.2 , and h=1mm) i obtain (S_21=-28.017dB)

2-case2:(ep_r=2.2,and h=4mm) i obtain(S_21=-28.954dB)

3-case3:(ep_r=10.2,and h=1mm) i obtain(S_21=-23.256dB)

4-case4:(ep_r=10.2 , and h=4mm) i obtain(S_21=-23.95dB)

you notice that in the case of the plane H , mutual coupling is strongest in the case3(ep_r=10.2,and h=1mm) and case 4(ep_r=10.2 ,and h=4mm) , and i found this result illogical because in (E plane) the mutual coupling is strongest when (ep_r and h) increse , and so do not have the same result in the H plane , becasue normally the mutual coupling is different in the 2 plane...what do you think?

thnak u

perhaps not clear my question !
sorry I'm a little weak in English

please ...
in H-plane coupling
../imgqa/eboard/Antenna/rf-cuw14tnwxb2.jpg

in a publication, they found that the coupling with (low permitivity +thick subsrat ) is strongest than the couplin with (high epr +thin substrat) but but I can not find this result , I find otherwise , coupling in (thin substrat +high permitivity) is strongest than the coupling with (thick substrat and low permitivity)
Can you tell me which is correct?

thank u very much!

all this is related to surface waves , I thought that may be momentum ads works with an infinite ground plane , is that in this case, momentum takes into account the surface waves?
thank u