Pyöreäpolarisaatiosuodatin

Pyöreäpolarisaatio, also known as circular polarization, is a type of electromagnetic polarization where the electric field vector of a propagating wave traces out a helix at a constant magnitude. This occurs when two perpendicular components of the electric field are equal in amplitude and have a phase difference of 90 degrees (pi/2 radians). Imagine a point on the wavefront as it travels; this point would appear to move in a perfect circle in the plane perpendicular to the direction of propagation.

There are two forms of circular polarization: right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The distinction depends on the direction of rotation of the electric field vector relative to the direction of wave propagation. If the vector rotates clockwise when viewed from the source, it is RHCP. If it rotates counter-clockwise, it is LHCP.

Circular polarization is often used in satellite communications and radar systems. For instance, transmitting and receiving antennas can be designed to use the same sense of circular polarization to minimize signal loss due to Faraday rotation, which can occur when electromagnetic waves pass through an ionized medium like the Earth's ionosphere. This polarization is also employed in some optical applications, such as in 3D movie glasses where different polarizations are used for each eye to create the illusion of depth.