If b a ,Ex and Hy are zero .why ?

[munna007]

if b >> a ,Ex and Hy are zero .why ?

hello friends...in schaum series book on Electromagnetic field theory , its shown that if b>> a then Ex and Hy are zero , and only components present will be Ey , Hx, Hz...
can you please tell me the reson for that...what happened when we made b >> a...
( i know that if a > b the all five components mentioned above r present...)

i have uploaded image of rectangular waveguide...

 

[pairofstrings]

It is just the way it is.

 

[a-tom-ic]

Do you really mean b >> a and not like in your picture a>b like for a usual rectangular waveguide? If you really mean b>>a, you might find the solutions with a parallel plate waveguide. Furthermore since I am curious, could you supply a amazon.com link to the book you use?

 

[PatrickEE]

I believe that in the Fourier solution to the 2D wave equation with the rectangular waveguide boundary conditions, Ex and Hy are proportional to sin(1/b), and if b is very large then this would make the components go to zero. I'm not sure if that's what the problem is stating though.

 

[munna007]

this is one of exercise question in exercise at the end of the chapter...there is not any description in any of the book...https://www.amazon.com/dp/0070212341/?tag=pfamazon01-20

above is the link for the book where i have found the question...

 

[artikk]

Hmm, I thought in rectangular waveguide problems, depending on type of boundary conditions used, the relevant tangential components to sides are 0. That might be why. For example, if a perfect magnetic conductor(pmc) boundary was employed at the left wall of the waveguide above, then Hy component at that wall would be 0 due to pmc condition and so on. Similar situation with the pec condition.