Talk:Waveguide (electromagnetism)

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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)

[edit] Merger

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):

• Simple analysis of rectangular guide in terms of superposed plane-waves / multiple reflections.

• Standard analysis of rectangular guide by solving Maxwell's equations by separation of variables.

• Ditto for circular guide.

• Mention of double-ridge guide etc.

• Definition of dominant mode. Uses of over-moded guide.

• Discussion of relative merits/uses of 2:1 rectangular guide, circular/square guide and two-conductor lines (coax/microstrip).

• Table of standard rectangular guide WG/WR.

• Mention of waveguide components (selection from: bends, transitions/tapers, junctions, magic-T, power-dividers, polarizers, filters, branch-couplers etc.) - with some more pictures!

• Mention of E-plane split construction of rectangular guide components.

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)

Although, there is also a page on Fiber Optics and its applications here on wikipedia. Perhaps one could reference that and do away with the optical waveguide article? Then again, if you plan to make this one that in depth, then I guess it would be alright to keep them separate. They just both seem too short at present, which is why I suggested it. Perhaps making the optics one more in depth as well could help.--Fred138 14:28, 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)

[edit] Pressurized guide

This is a surprising statement:

"In some waveguides, there may be a positive gas pressure internally present, allowing for the detection of potentially dangerous RF leaks. Another solution to detect RF leakage of a waveguide is to have a partial vacuum present inside. Then leaks can be detected in basically the same way."

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)

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)