Is it possible to calculate THEORETICALLY the resonance frequency of an antenna with the current distribution?

[xabierzu]

Hi, i am trying to design a triple band rectangular patch and i would be doing so by introducing slots that modify the current path, generating that way two other resonance frequencies. But before jumping into cst and doing endless parametric sweeps i would like to theoretically prove it. How can i prove a resonance frequency from the current distribution expression?

Thx!