Newbie question lambda g
Hi, im totally new to uw, but have a 4th Ed book by Pozar and am slowly plowing through it. I have an Elec Eng degree but been out if it for years doing IT, so Im learning a lot of this from scratch as a hobby.
My question is with a WR430 waveguide, for calculating where 1/4 wavelength locations should be along the waveguide - should i use the free air wavelength, or use the lamdba g ( waveguide wavelength)?
I believe you should use lambda guide, as described here
But I would hold out for a second opinion!
Agreeing with the previous answer and from what I've learned, I would say wavelength in a waveguide is modified with regards to the wavelength in an unbounded medium by the m and n indexes of the mode that you consider, as the propagating wave is not a perfect plane wave unless you go very high in frequency...
You can also check your Pozar(MWEng, 4ed. p112), Balanis(Adv.Eng.Electromags,1ed. p354) or Ramo (Fields&Waves in CommElectr, 3ed. p418) or go to the classics: Marcuvitz (WaveguideHandbook, Ch1)
Hope this helps.
Also, from Feynman lectures, which are very easy to read through, you can see it´s in line with Microwaves101: see formula (24.19), you can find the lecture on this link
You need to use lambda g which is the wave length inside the wave guide for a particular frequency
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