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SLAC defn: A waveguide is an evacuated rectangular copper pipe. It carries electromagnetic waves from one place to another without significant loss in intensity-- Light current 01:54, 31 January 2006 (UTC)
I have suggested merging this article with optical waveguides, as optical waves are higher frequency electromagnetic waves. I think the problem could be solved if optical waveguides was made a subsection of this article. -- Fred138 01:44, 11 October 2006 (UTC)
Hi. I was planning to expand the Waveguide (electomagnetism) page considerably. I've only got as far as rewriting the introduction and adding a picture, but I was intending (eventually):
This might make a merged page a bit long and a bit one-sided (weighted towards hollow metal guides). Of course there's no real physical distinction between microwave and optical guides, but the technology is a bit different so it's a convenient split. So I have a slight preference for separate pages. -- catslash 13:34, 11 October 2006 (UTC)
Personally, I have no plans to make the Waveguide (optical) page more in-depth. Also, there is a speaking tube page to cover the acoustic case. So I'm persuaded that merging is a good plan. If, in the distant future, this article becomes too long, then we can think again, and (say) split dielectric guides from hollow metal guides. -- catslash 14:48, 11 October 2006 (UTC)
I don't think merging them is a good idea. Hollow metal microwave guides are sufficiently different from dielectric optical waveguides to merit two articles. Whether one makes the break by wavelength or by hollow metal vs. dielectric is a matter for discussion. Note, though, that not all optical waveguides are fibers. Non-fiber optical waveguides are extremely important technologically. They are widely used in photonics and semiconductor lasers.-- Srleffler 08:52, 11 November 2006 (UTC)
The sentence "A wave guide is used to guide waves" assures a non Scientist/Engineer will have no idea what the rest of the article is about. Suggested change: A Waveguide is used to transport an electrical signal, prevent an electrical signal from leaking via radiation. Filter unwanted components of an electrical signal.
This is a surprising statement:
I think there may be some confusion here. Waveguides are sometimes pressurized to inhibit arcing/ multipaction, and are sometimes evacuated because they are part of evacuated systems (e.g. electron beam systems), but I've never heard of pressurization to detect breaches. Are there any references to support this claim? -- catslash 23:20, 8 September 2006 (UTC)
The "pressurize to determine dangerous leaks" is the wrong answer on the beginners radar test. - Bogus, going to change it. 71.110.64.173 23:11, 1 July 2007 (UTC)
You could have a horn feed for a cassegrain antenna for example that would require a weather-tight dielectric window across the aperture. You would need to make the whole waveguide system gas tight with rubber gaskets and then put in a slightly positive gas pressure of some suitably dry high breakdown gas and monitor the flow rate. If you get a small leak you can detect the increased flow rate and hopefully it will keep the rain and dust out until you can repair it. ChrisAngove 20:00, 24 November 2006 (UTC)
Bad pressurized WG info replaced. Fubartu 00:25, 2 July 2007 (UTC)
We bady need some stuff on the dummy loads used with WG. Any offers? -- Light current 23:01, 25 January 2007 (UTC)
Hi all. I'm just here disambiguating "Beam" and this isn't my field but the WG article TITLEs are a little muddled. Might I suggest that:
Reasons:
I've drop this in Waveguide, WG(em) and WG(opt) as there doesn't seem to be much overlap between the "talkers". Enjoy, Saintrain 18:03, 12 February 2007 (UTC)
I would recommend not merging the two pages together. Instead you may want to retitle waveguide (electromagnetism) to waveguide (RF) or waveguide (microwave). Optical waveguides are almost exclusively fiber optic based where RF/microwave/millimeter wave waveguides are almost always hollow metallic tubing. Two very different concepts. —The preceding unsigned comment was added by 199.46.200.233 ( talk) 23:07, 15 March 2007 (UTC).
Concerning this sentence: Waveguides are highpass filters.
I believe they are not high-pass (neither low-pass). Googling did not confirm article sentence. Kar.ma 17:54, 28 January 2009 (UTC)
98.81.3.202 ( talk) 02:23, 17 April 2012 (UTC)
"Transmission lines such as microstrip, coplanar waveguide, stripline or coaxial may also be considered to be waveguides". No. a waveguide is a kind of transmission line, not the other way around. Transmission line is a general term that is applicable to ALL structures aimed at transporting EM energy (including optic) from one point to another. This includes twisted pairs, waveguides and optical fiber. By the way a sound pipe is NOT a waveguide.
A waveguide can act as a high pass filter or attenuator, but they are NOT filters.
Why is there another waveguide entry? Filled with much bogus and wrong info. Why can not people who have little to contribute, or not qualified to contribute keep their hands off these articles? Just asking... —Preceding unsigned comment added by 173.77.162.40 ( talk) 20:02, 26 February 2011 (UTC)
I moved this to the talk page because it could be part of the article, but it was in the wrong place and there is not a place in the article where it could be dropped in. It gives the solution for a particular wave guide, the hollow rectangular wave guide. The article was discussing wave guides in general where it was. If this was added to the article, it would need some supporting information such as variable definitions, probably a figure and needs to discuss that it pertains only to the one type of wave guide. There is no place in the article that this could be dropped in without more work.
With a Helmholtz below:
using the boundary conditions of z (unlimited space) which can deduce a solve:
and using the boundary conditions of x and y, inserting the standing wave equation:
As we can know should be an another constraint equation. So for each has two modes in it which are called TE and TM modes introduced below.
Constant314 ( talk) 01:55, 15 January 2016 (UTC)
I believe recent posts about the existence TEM modes in hollow wave-guides are using the terminology incorrectly or confusedly. It is true that a propagating TE mode can be decomposed into the superposition of two plane waves, each of which is TEM to its own direction of propagation. However, neither plane wave is a mode of the wave-guide because neither will satisfy the boundary conditions or the wave-guide. Further, there is a statement that non-propagating TEM modes form the propagating TE modes. If the TEM modes were not propagating, then it would not extend far enough into the wave-guide to form TE modes deep in the wave-guide.
Constant314 (
talk)
13:08, 6 May 2016 (UTC)
Pragnan Chakravorty 19:22, 6 May 2016 (UTC)
It is important to note that the edits didn’t refute the common notion of TEM being non-propagating in a waveguide. It only supported this notion in a different way. We should appreciate the fact that electromagnetic waves are intrinsically TEM in nature, had it been not so, we would have had TE or TM modes even in free space. In other words, if TEM mode doesn’t exist in a waveguide then how does it reappear when the waves come out of the guide?
If we ask ourselves that can the waves exist without propagating, then the answer is obviously yes, the examples are standing waves or evanescent waves which do exist without propagating. Inside a waveguide, if the z direction is open for wave propagation, then TEM waves along x and y axis form standing waves. These standing waves would impress either their electric fields or magnetic fields along z direction (direction of propagation) to form TM or TE modes respectively. This is how non propagating TEM waves can give rise to propagating TE or TM waves inside a waveguide. A detailed analysis of this phenomenon is given in the cited article.
Please write to me at pciitkgp@ieee.org, if you don’t have access to this article. The article has been published by a renowned publisher after it has undergone a rigorous peer review.
I understand that you may not like to get your text edited by anyone else; in that case, I would request you to read this article and include its basic idea in your text so as to provide a more holistic discourse on waveguides.Pragnan Chakravorty 19:22, 6 May 2016 (UTC)
I have emailed you the article.Please also consider the following comments to better understand my point of view:
Why TEM must exist:
Electromagnetic waves by their very nature are TEM. No electromagnetic wave generator can create a propagation mode other than TEM (i.e. they can’t create a stable TE or TM mode which can exist in free space or any arbitrary bound or unbound medium). It is important to note that even in the Maxwell’s equation the electric field, the magnetic field and the direction of wave motion must all be orthogonal to each other due to the curl operators, i.e. if the electric fields or magnetic fields are directed along the wave motion then Maxwell’s equation can’t be held true. In a waveguide, the very existence of TE and TM modes are attributed to the electric or magnetic fields contributed along the direction of propagation (along the open ends of a waveguide) by the standing TEM waves; if there were no TEM, even TE and TM would not exist.
Why TE and TM are only temporary impressed modes:
To understand this in a simple way, we can assume that when TEM waves are launched inside a waveguide, they tend to move along all three orthogonal directions (i.e. x, y and z of Cartesian coordinate system); if z is along the open ends of the waveguide then standing waves are formed along x and y direction. But these standing waves being TEM direct their electric or magnetic fields along z; these electric and magnetic fields along z direction get impressed upon the TEM wave moving along z direction. Thus TE and TM modes are temporarily impressed due to the boundary conditions. The moment these boundaries are gone, these impressed modes are also gone; therefore, TEM waves along all three orthogonal directions remain juxtaposed with each other, within a waveguide, in a way that TE and TM modes are impressed. It is important to appreciate the fact that TE and TM are only temporary modes and they can’t exist without a waveguide.Pragnan Chakravorty
182.66.12.162 (
talk)
05:51, 7 May 2016 (UTC)
We should sacrifice the little space needed to present the mm values more accurately. I've just checked WR51 which is supposed to be 12.954 mm wide but is indicated as 13.0 mm. — Preceding unsigned comment added by 153.92.184.111 ( talk) 13:42, 28 November 2017 (UTC)
@ Fgnievinski: You recently changed the title disambiguation from Waveguide (electromagnetism) to Waveguide (radio frequency). I agree that "electromagnetism" is not a terribly good title, but "radio frequency" is problematic as well. Waveguides are generally used in the microwave bands (the higher microwave bands at that) and radio frequency is often used in contrast to microwave in the literature. I suggest Waveguide (microwaves) is more appropriate. The only fly in the ointment with that is that the article currently seems confused over whether it wants to include optical waveguide (which makes radio frequency even more inappropriate). The hatnote suggests that it is not included, but nevertheless, both the lead and the body discuss it. Spinning Spark 11:49, 6 November 2019 (UTC)
@ Constant314: I think the answer is as follows (but I wouldn't stake my life on it). In a TEM wave the components of curl d/dx Ez and d/dy Ez cannot exist because they a require a z component of E, and d/dx Ey and d/dy Ex cannot exist because they produce a z component of B. That just leaves d/dz Ex and d/dz Ey which result in the E field varying along the length of the guide. I don't think that can happen in a lossless guide with dimensions invariant with z. Why don't you get the cited source from the Library if you think the statement is dubious. Spinning Spark 20:55, 13 March 2020 (UTC)
Hello,
I was considering adding various results about rectangular waveguides as well as the mathematical developments necessary to obtain them (a priori starting from Maxwell's equations)
The whole thing would be illustrated by pictures I made.
Some of these concepts are already covered somewhere on wikipedia in a very general context. I propose to explore them specifically for rectangular waveguides. Is this interesting? Is it more appropriate to create a new page dedicated to rectangular waveguides and their analysis? Is it convenient to write the entire math development or only the main results? Or a brief and simplified reasoning with links to books and other sources?
Thanks for your advices
VK Vivien ( talk) 09:42, 24 April 2020 (UTC)
It seems to me that the main subject of this article is the hollow waveguide, commonly shortened to just waveguide. I will make a redirect for it, but I suspect that hollow waveguide might be a better name for the article. Gah4 ( talk) 20:35, 24 April 2020 (UTC)