How are Tranverse Magnetic and Transverse Electric Polarisations defined?

In summary, Polarisations are used to define the orientation of electromagnetic fields relative to the axis of a cylindrical wave guide. This includes transverse electric (TE), transverse magnetic (TM), and transverse electro-magnetic (TEM) modes, with TEM only existing in non-simply connected cross sections. These modes allow for undisturbed signal propagation along the wave guide due to their lack of dispersion.
  • #1
StephanJ
4
0
I've seen this terminology being used a few times and knowing what it means exactly would be great. I gather that it's used to define Polarisations relative to a plane?

Any help would be great.
 
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  • #2
The terminology usually applies for cylindrical wave guides, where the cylinder can have any cross section, not only a circular one. One can prove from Maxwell's equations and the appropriate boundary conditions for the fields that each em. field can be expanded in a set of three types of eigenmodes that are

transverse electric (TE): The electric field has no component in direction of the cylinder axis,
transverse magnetic (TM): The magnetic field has no component in direction of the cylinder axis,
transverse electro-magnetic (TEM): both the electric and the magnetic field have no component in direction of the cylinder axis.

So, transverse is meant with respect to the cylinder axis. The TEM modes only exist if the cross section of the cylinder is not simply connected. A typical example is the usual caxial cable. These modes are particularly nice since they show no dispersion (in an ideally conducting wave guide), i.e., they admit an undistrubed signal propagation along the wave guide.
 

1. What is the difference between Transverse Magnetic and Transverse Electric polarisations?

The main difference between Transverse Magnetic (TM) and Transverse Electric (TE) polarisations is the orientation of the electric and magnetic fields. In TM polarisation, the electric field is perpendicular to the direction of propagation, while in TE polarisation, the magnetic field is perpendicular to the direction of propagation.

2. How are Transverse Magnetic and Transverse Electric polarisations defined?

TM and TE polarisations are defined based on the direction of the electric and magnetic fields. In TM polarisation, the electric field is perpendicular to the direction of propagation and in TE polarisation, the magnetic field is perpendicular to the direction of propagation.

3. What is the significance of Transverse Magnetic and Transverse Electric polarisations in electromagnetic waves?

TM and TE polarisations are important in understanding the properties and behavior of electromagnetic waves. They can affect the reflection, refraction, and transmission of waves in different materials and can also impact the polarization state of light.

4. Can Transverse Magnetic and Transverse Electric polarisations exist simultaneously?

No, TM and TE polarisations cannot exist simultaneously in the same electromagnetic wave. This is because they have perpendicular electric and magnetic fields, and an electromagnetic wave can only have one direction of polarization at a time.

5. How can Transverse Magnetic and Transverse Electric polarisations be manipulated?

TM and TE polarisations can be manipulated using polarizing filters, which can selectively block one type of polarization and allow the other to pass through. They can also be manipulated by changing the orientation of the materials the waves pass through, or by using devices such as waveplates or polarizers.

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