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[Abu Maria.]

hi.
please ...
in H-plane coupling between (02)patch antenna

http://images.elektroda.net/49_1338823961.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?

[bigSteve]

The answer should be found intuitively.

When the permittivity is high, the fields are tightly bound. In addition, in high permittivity substrates the wavelength is shorter than in low permittivity substrates. Hence, two antennas are electrically farther apart in higher permittivity materials (more wavelengths separation). Therefore, when the permittivity is high, the antennas will couple together less because the fields are tighter bound and the wavelength decreases.

The same effect occurs for lower height patch antennas - the fringing fields are more tightly bound. Hence, the fields will extend less beyond the antennas and couple together less than patch antennas with high substrates.

Therefore, the correct answer is: the coupling with high substrates and low permittivitty will be strongest.

[Abu Maria.]

very good intuition! big...
but
i simulate (02) patch antenna ,one time with (low epr , high substrates ) and in other time with (high permitivity , low substrates)
and
I find the opposite of what you say,

the coupling with high substrates and low permittivitty will be weakest.

i do simulation with ADS MoMentum (2006)
can you advise me, where is the problem!?
thank u big