In reality CP does not exist. It is better to say multi-polarization. The easiest way to see if your antenna has CP in simulation is to check for the S11 and AR results around the resonant frequency. There should be two picks for S11 with your design freqquncy being at the middle. These two picks indicates the two E-fields. You can also see the angles between them from your AR generated file in CST or HFSS. Your AR should be close to 1 or 0dB. See the attachments below from my multi-polarized antenna.

Thanks for the help. What value of angle phi and theta u take for axial ratio at desired resonant frequency??

After getting AR, What value of angle phi and theta we need to take for lhcp and rhcp

check the attached image for details

thanks again. since ur antenna has axial ratio below [email protected] and u take phi=90 and theta all to check for AR.

finally, to confirm lhcp or rhcp, should we take angle phi=90 and theta all ??