What are circularly polarized electromagnetic waves?

Circularly polarized electromagnetic waves are characterized by electric and magnetic field vectors that rotate as the wave propagates through space. Instead of oscillating in a single fixed plane, such as in vertical or horizontal linear polarization, the tip of the electric field vector traces out a corkscrew or circular pattern along the direction of travel. It is important not to confuse the rotation of the field with the physical path of the radio wave itself. The wave does not travel in a circular path or bend around the Earth; rather, it travels in a straight line while its internal fields rotate. Furthermore, a standard loop antenna typically produces linearly polarized waves, not circularly polarized ones.