waveguide stairs
I need do the stairs in waveguide - see the picture, it is model of "waveguide hole".
Can you tell me, how can I predict the design of stairs? Have you some theory or can you tell me, where can I find it?
Thank you!
Is there an E-field probe that you did not draw?
Those "stairs" are quarter wave impedance transform sections. You choose the wave impedance to match the end impedance. Mathaie, Young, and Jones have a section on such transformers. Other older papers exist with titles like "chebychev impedance transformers", etc.
Thank, but I can not find "chebysev impedance transformers", do you know, where can I find "good" theory? How can I calculate the dimensions of the stairs?
Are you sure, that is it QUATER wave impedance transform sections?
Here are some links
http://cc.ee.ntu.edu.tw/~leonardo/note/chap6.pdf
http://ceta.mit.edu/pier/pier86/18.08100605.pdf
http://www.ittc.ku.edu/~jstiles/723/...er_package.pdf
http://www.wipl-d.com/products/bench...oax_cheb_t.php
http://www.ece.rutgers.edu/~orfanidi/ewa/ch12.pdf
Added after 8 minutes:
Be aware, they spell chebychev differently in different countries.
I would bet they are quarterwave steps. They could be other lengths, like 3/4 wave, but you would end up with 3X less bandwidth for the impedance transform(I think).
Rich
OK, thank, but, How can I change impedance of rectangular waveguide?
Exactly:
see the picture: Z = kη/β, η=η0=377 Ω; k=ω√με, β=√k2-kc2
and kc = √(mπ/a)2+(nπ/b)2
but for TE10, m=1 and n=0, so the "(nπ/b)2" = 0 and ? the impedance Z is independent of the dimension "b".
a - longer sides of the waveguide
b - shorter sides of the waveguide
I need to do stairs in the "b-plane"
Thank
Yes, you are right, the wave impedance in the TE10 mode does not depend on b(height). Never the less, this is how it is done. I would refer you to Mathaei, Young, and Jones section 6.08 (pages 300 - 304) for an example of matching two equal width waveguides by means of stepped height quarter wave sections.
maybe you do not think of it as actual quarter wave impedance sections, but rather as a series of height discontinuities spaced by quarterwave? Theory of small reflections?
Some emag guy can jump right in here and comment!
Hi,
can you tell me, what do you think:
"Mathaei, Young, and Jones section 6.08 (pages 300 - 304)"
- what is it, it is book?
Thank
Yes, a very good book for microwaves:
http://www.amazon.com/Microwave-Impe...2764182&sr=8-1
I not to have it, unfortunately.