The magnitude of the currents should be larger than zero.
I surmise from these questions that you aren't understanding the operating mechanism of the patch antenna. See texts such as Balanis or even Wikipedia.
@planarMetamaterials: thanx for reply... i know how an antenna operate and i have designed a multiband antenna but i don't know what should be its range (mean maximum upper range limit for working antenna ) my antenna has range of 37 A/m ,60 A/m 45 A/m for different bands
@planarMetamaterials: thanx for reply... i know how an antenna operate and i have designed a multiband antenna but i don't know what should be its range (mean maximum upper range limit for working antenna ) my antenna has range of 37 A/m ,60 A/m 45 A/m for different bands
Sorry for the misunderstanding -- I'm still confused, though -- are you asking what's the maximum current density a typical patch antenna can handle before overheating?
Well.... that would depend on a number of factors, such as dielectric material and thickness, trace thickness, ground plane size (for thermal dissipation), etc.