Components of E for a waveguide problem.

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Homework Help Overview

The discussion revolves around the components of the electric field (E) in a rectangular waveguide problem, specifically focusing on the relationship between the amplitudes A1 and A2 in the given equations for Ex and Ey. The original poster attempts to show that A1 = -A2 k2 / k1 based on the provided equations.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the possibility of substituting A1 into the equation for Ex to demonstrate equivalence with Ey. There is also mention of using matrices, though some express uncertainty about this approach. Others suggest manipulating the original equations to derive the relationship between A1 and A2.

Discussion Status

The discussion is active, with participants exploring different perspectives on how to approach the problem. Some have recognized the vector nature of the components, which may influence their reasoning. There is acknowledgment of the need for additional constraints to fully resolve the relationship between the amplitudes.

Contextual Notes

Participants note that the equations represent vector components of the electric field, and there is a suggestion that a missing constraint may be affecting the analysis.

atomicpedals
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Homework Statement



For a rectangular wave guide the components of E were found to be

Ex = A1 cos( k1 x) sin(k2 y) e-i ([tex]\omega[/tex]t-[tex]\gamma[/tex]z)

Ey = A2 cos( k1 x) sin(k2 y) e-i ([tex]\omega[/tex]t-[tex]\gamma[/tex]z)

Ez = 0

Show that in these equations A1 = -A2 k2 / k1

Homework Equations



See part (a)

The Attempt at a Solution



My first instinct is simply substitute this given A1 into the x equation and show its equivalence to the second. But I'm not so sure that's the best way to go about it (or even the correct way to go about it). It would be tempting to solve this using matrices but that doesn't seem appropriate.

So, any suggestions as to if I'm on the right track or way off base are much appreciated!
 
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hi atomicpedals! :smile:
atomicpedals said:
Show that in these equations A1 = -A2 k2 / k1

hmm :rolleyes: … that's the same as k1A1 + k2A2 = 0 …

how could you manipulate the original equations to get that? :wink:
 
Aww fer crying out loud, they're vector components (facepalm)... yeah, leave it to me to miss the bleedin' obvious!

Thanks!
 
tiny-tim said:
hi atomicpedals! :smile:


hmm :rolleyes: … that's the same as k1A1 + k2A2 = 0 …

how could you manipulate the original equations to get that? :wink:

I don't get it.
 
The fist thing I failed to see right off the bat was that each equation was a vector component. That is E = ( Ex , Ey , Ez )

So looking at it like that there are a number of ways to get it down to the simple algebraic form (divergence or laplacian ...I'll need to crunch the numbers).
 
Ignoring Ez, in your problem statement you have two equations whos amplitudes are independent. There's a missing constraint.
 

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