Does the E Vector of a Polarized EM Wave Trace an Ellipse in Space?

AI Thread Summary
The discussion centers on the behavior of the electric field vector of a polarized electromagnetic wave, specifically in relation to its elliptical polarization. When fixing the spatial coordinate z, the electric field vector traces an ellipse over time, indicating the temporal aspect of polarization. The inquiry arises about the electric field's behavior when fixing time and varying z, with the suggestion that it will also vary with z. The consensus is that changing z or time is equivalent since z represents the direction of wave propagation. The conversation highlights a gap in understanding spatial variation in polarization, which is often overlooked in educational contexts.
ask_LXXXVI
Messages
53
Reaction score
0
Let us consider the Electric field components of a polarized EM wave .
[PLAIN]http://www.cdeep.iitb.ac.in/nptel/Electrical%20&%20Comm%20Engg/Transmission%20Lines%20and%20EM%20Waves/graphics/CHAP%204__255.png.

Now if we fix the value of z (for convenience take z=0) and consider the locus of the Electric field vector over time, we get an ellipse in general. This is what is meant by elliptical polarization. Now this is the temporal aspect. That is - at a fixed location of space , the E vector keeps changing its direction with time (while staying in the plane perpendicular to direction of propagation)

My doubt is what is the behavior when we fix the value of t (let us take t=0 for convenience) and consider the locus of the Electric field vector with respect to the variation in z. Will we get a change in direction of Electric field vector as we change z?

My personal opinion is that it will vary with z also,as the cosine terms in the equation look similar if we suppress either z or t by keeping them fixed . I just want to have a confirmation.
It would be a great help if someone directs me to a website containing an applet which helps in visualizing this particular situation
 
Last edited by a moderator:
Engineering news on Phys.org


If z is the direction of propagation, then changing z or changing -t is indeed the same.
 


0xDEADBEEF said:
If z is the direction of propagation, then changing z or changing -t is indeed the same.

yes z is the direction of propagation .


I guess the spatial variation of the E vector wasn't discussed in the course I took as Polarization deals with the temporal behavior of the fields and not the spatial.
 
Thread 'Weird near-field phenomenon I get in my EM simulation'
I recently made a basic simulation of wire antennas and I am not sure if the near field in my simulation is modeled correctly. One of the things that worry me is the fact that sometimes I see in my simulation "movements" in the near field that seems to be faster than the speed of wave propagation I defined (the speed of light in the simulation). Specifically I see "nodes" of low amplitude in the E field that are quickly "emitted" from the antenna and then slow down as they approach the far...
Hello dear reader, a brief introduction: Some 4 years ago someone started developing health related issues, apparently due to exposure to RF & ELF related frequencies and/or fields (Magnetic). This is currently becoming known as EHS. (Electromagnetic hypersensitivity is a claimed sensitivity to electromagnetic fields, to which adverse symptoms are attributed.) She experiences a deep burning sensation throughout her entire body, leaving her in pain and exhausted after a pulse has occurred...
Back
Top