Elliptical depolarization ratio

From AMS Glossary
Jump to: navigation, search

elliptical depolarization ratio

The ratio of power received in the transmission channel to power received in the orthogonal channel of a dual-channel radar, when an elliptically polarized signal is transmitted. For a weather target, this ratio depends, in general, on the ratio of the major to the minor axis of the polarization ellipse, the orientation of the ellipse, and the depolarizing characteristics of the hydrometeors that constitute the target.

Typically, the ratio will be less than unity (or a negative decibel quantity) when the major and minor axes are comparable in size and the polarization ellipse is close to circular, but will be greater than unity (or a positive decibel quantity) as the polarization ellipse becomes sufficiently elongated on either of its axes. A greater depolarization ratio is achievable with elliptical than with circular polarization by matching the axial ratio and the orientation of the transmitted signal to the depolarizing characteristics of the target.
Compare cancellation ratio, circular depolarization ratio.

Personal tools