cst axial ratio

Good morning,

i have some problem with CST microwave studio 2008. I have designed a square patch with trim corner for circular polarization (E-PLANE is ZY and H-PLANE is ZX). The CST axial ratio is defined over theta and phi component of e-field. I desire obtainer a axial ratio define as ratio of efield over X and efield over Y. What passes are necessary for the conversion of above mentioned axial ratio??

thank you for courtesy,

Giacomo:D