Ashish
here we go. our example here is a patch, E-field is in the direction of the field lines, so theta=90 for variable phi is E plane, H-plane is phi=0 and theta=0 to 180. and the polarization of the patch antenna here is horizontal polarization, right? since the polarization is the trace of the E-field line.
Co polar curve for E field is theta=90 for phi, horizontal polarization, what would be the theta(cross polar) which would make it vertical polarization, theta=0 right.
Similarly for H-field co polar curve phi=0 for varibale theta what would make the polarization orthogonal phi=90(cross polar curve)
Hope that helps man.
I tried my best, and believe me i am not a good teacher have experienced it myself. if you find it difficult to understand kindly let me know one more time
Regards
Elchiquito.