# source of rectangular breakdown power formula

#### yef smith

Joined Aug 2, 2020
381
Hello, I have a regular waveguide with regular room pressure no special gas in it.
Is there some book or manual where i cood calculate the breakdown power to it?
I have found the formula bellow,but its without a reference.
taken from a calculator.
Is there some book or manual where i could see this formula in it?

Thanks.

#### Tesla23

Joined May 10, 2009
517
I have no idea if that is correct, but all you have to do is to integrate the poynting vector across the cross section for the propagating mode, and limit the E field to the max allowed.

http://www.introni.it/pdf/10 - Waveguide Handbook.pdf

#### yef smith

Joined Aug 2, 2020
381
Hello Tesla,i could not find in the link input breakdown power.
Could you help me with some article or a book where we could see the formula for
rectangular waveguide in simple room conditions breakdown input power?
Thanks.

#### AlexeyEg

Joined Feb 17, 2022
2
The engineer of the old school knew Russian. Page 205, first third.

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#### AlexeyEg

Joined Feb 17, 2022
2
With standard waveguide sizes (a = 0.75 λ; b = 0.5 a), substituting the limit value E0 = 30 kV / cm, it can be determined that the limit power of the wave H10 is equal to P = 125λ2 kW, where the wavelength is expressed in centimeters. For example, at λ = 30 cm, the maximum power P = 112 MW. Accordingly, the permissible power is 28 MW. Consequently, considerable energy can be transmitted through a rectangular waveguide.

#### yef smith

Joined Aug 2, 2020
381
Hello Alexey, Thank you very much for the book.
In the formula you pointed i cant understand what is K and Z_b?
K is wave number? 2*pi/lambda? am i correct?
What kind of impedance is Z_b ?
What values did youput in the formula for K and Z_b?
thanks.