Circular Polarized Antenna Reflection Coefficient

Dear all,

Is it always necessary that the circularly polarized antenna should show a 'w-shape' at the resonant frequency in the reflection coefficient graph?

Thanks in advance :)

I'm not sure what a "w" shape refers to specifically, but no, there is no such requirement on the qualitative form of the reflection coefficient.

Thanks very much for your reply :)

It is said that the 'w-shaped' means the two v shapes of the w are the orthogonal components of circular polarization. If you can help me regarding this, it would be helpful.

I assume you're referring to the frequency-domain. That could be the case, but it's hard to say without any supporting information about the antenna in question. Many antennas support both polarizations at the same frequency.

It looks like this

Any help regarding this ?