Search results
Results From The WOW.Com Content Network
In electrodynamics, circular polarization of an electromagnetic wave is a polarization state in which, ... Crossed-dipole antenna array of station KENZ's 94.9 MHz, ...
Note that for circular polarization, optical researchers use the opposite right-hand rule [citation needed] from the one used by radio engineers. It is best for the receiving antenna to match the polarization of the transmitted wave for optimum reception.
Most antennas are nominally linearly polarized, but elliptical and circular polarization is a possibility. In the case of linear polarization, the same kind of filtering as described above, is possible.
Helical antennas can receive signals with any type of linear polarisation, such as horizontal or vertical polarisation, but when receiving circularly polarized signals the handedness of the receiving antenna must be the same as the transmitting antenna; left-hand polarized antennas suffer a severe loss of gain when receiving right-circularly ...
Circular polarization was used for spacecraft (satellite and missile) communication, since circular polarization is not sensitive to the relative orientation of the antennas, and the space vehicle's antenna could have any orientation with respect to the ground antenna. High gain Yagi turnstile antennas were often used for the ground station.
This antenna is unusual in that it radiates in all directions (no nulls in the radiation or reception pattern), with horizontal polarization in directions coplanar with the elements, circular polarization normal to that plane, and elliptical polarization in other directions. Used for receiving signals from satellites, as circular polarization ...
In a transmitting antenna, XPD is the fraction of power from an antenna of one polarization radiated in the other polarization. For example, due to minor imperfections a dish with a vertically polarized feed antenna will radiate a small amount of its power in horizontal polarization; this fraction is the XPD.
Vivaldi antennas can be made for linear polarized waves or – using two devices arranged in orthogonal direction – for transmitting / receiving both polarization orientations. If fed with 90° phase-shifted signals, orthogonal devices can transmit/receive circular -oriented electromagnetic waves .