For a linearly polarized antenna, state the orientation relative to the installed coordinate system and the permitted cross-polar response. For circular polarization, state RHCP or LHCP with the agreed viewing convention. Axial ratio indicates how close the polarization ellipse is to a circle; it must be limited over the required frequency and angular region, not only at boresight.
Cross-polar discrimination compares desired and orthogonal polarization responses under a declared basis. It is distinct from isolation between two feed ports. Dual-linear and dual-circular designs may require both port isolation and pattern-level cross-polar limits.
Polarization mismatch reduces received power and can vary with platform attitude, reflection and radome effects. Include the operational orientation, angular coverage, radome and representative installation in verification.