Plz explain polarization:

Plz explain polarization:


1 Answers

askIITIians Expert
21 Points
15 years ago



Sharp eyed travelers will notice that most TV antennas on British rooftops are verticle but in the U.S they are horizontal. The difference comes about because the British elect to tranmit their TV signals so that the electric field vectors oscillate in a vertical plane. In this country-with equal arbitrariness-we have chosen to have them oscillate in a horizontal plane.

The wave characteristics that enters here is its polarisation. The plane defined by the direction of propagation and the direction of polarization is called the plane of vibration.

Electromagnetic waves in the radio and microwave range readily exhibit polarization. It is generated by surging of charge up and down in the dipole transmitting antenna and so has an electric field vector.

When the polarized wave falls on a second dipole connected to a microwave receiver, the alternating electric component of the wave will cause electrons to surge back and forth in the receiving antenna: this will produce a reading on, say , a microvave detector in the receiver. But if we turn the receiving antenna through 900 about the direction of propagation, the detector reading will drop to zero. In this orientation the electric field vector is not able to cause charge to move along the dipole axis because it points perpendicular to this axis. Check this out with your rabbit ears TV antenna.

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