Why is the electric field in y direction in a TE guided wave?

[happyparticle]

TL;DR Summary

Direction of the electric field in a transverse electric guided wave.

Hi,
I have a fairly simple question, but the answer is probably not as simple.
I'm not sure to understand why in a guided wave (TE), the electric field is in the y direction.
I know $E_z = 0$, but why $E_x = 0, B_y = 0$?

 

[DrClaude]

You will have to give details of the situation you are considering. The orientation of the cartesian coordinates is arbitrary.

 

[happyparticle]

I have wave guide of rectangular shape with height a and width b.

 

[DrClaude]

I have wave guide of rectangular shape with height a and width b.

Along which axes?

 

[happyparticle]

Sorry,
$\hat{x}$ is horizontal, $\hat{y}$ is vertical and the direction of propagation is $\hat{z}$

 

[DrClaude]

Sorry,
$\hat{x}$ is horizontal, $\hat{y}$ is vertical and the direction of propagation is $\hat{z}$

Then if $E_x=0$ is because the E field is polarized along y (i.e., it doesn't need to be 0). $B_y = 0$ since it is a TE mode.