What type of polarization is produced by crossed dipoles fed 90 degrees out of phase?

When two dipole antennas are mounted perpendicularly (crossed) and fed with signals that are exactly 90 degrees out of phase, their combined electric fields interact to produce circular polarization. Because the two signals are offset in time by a quarter of a wave cycle (90 degrees), the peak amplitude of the electric field continuously transitions from one dipole to the other. This creates an electric field vector that rotates as it propagates forward. It is a common misconception that crossed antennas will cancel each other out or just create a messy "cross-polarization." In reality, the specific 90-degree phase shift prevents cancellation and is a classic, practical method for building circularly polarized satellite antennas, such as turnstile arrays.