Hello to all
Two questions
1. Does the use of metals with high magnetic permeability, such as iron alloy in the waveguide, cause insertion losses?
2- What about chrome or copper plating?
If you know the article in this field, please introduce it. Thank you
Use of metals with high permeability results in high losses because it reduces the skin depth. Twice the skin depth is the thickness of metal most of the current flows in. Read about the skin effect in Wikipedia
https://en.wikipedia.org/wiki/Skin_effect
For copper at 10 GHz all the currents in a waveguide flow on a layer less than a micron thick on the inside walls. For magnetic materials the layer is even thinner. Anything thicker than this doesn't change the microwave performance, so a layer of copper a micron thick on the inside of a magnetic iron waveguide will give the same performance as a copper waveguide. Silver is best, because it has the lowest resistivity. You need to know where the current flows. For instance on microstrip most of the current is on the bottom of the track, so it is no good putting copper on top of something worse, the copper has to be on the bottom of the track.
Hi
I could not find a paper regard to your question but this article addressed its title below has suggested a new method for minimizing the waveguide's size. In this method, the waveguide has been filled with metamaterial:
Waveguide miniaturization using uniaxial negative permeability metamaterial
Dear Vahid
This issue is addressed in various textbooks, including the academic references in Electromagnetism. while the frequency and the skin-depth are in a tied relationship, some other factors effects the overall performance of waveguide structures. all of these factor are modeled in original Maxwell equation as innate properties is materials.
Regards
Ahmad
in addition to what Malcom said (ferromagnetic material is bad unless you would like to build an attenuator) due to strongly reduced skin depth and thus high losses; copper coating is good but watch out about technological issues in particular on stainless steel..it does not stick there very well. And copper tends to oxidise .One may consider adding a VERY thin layer of gold (below 0.1 micron) to prevent oxidation. For the other question "How to reduce the diameter of a waveguide first have a look at single or double ridged waveguides..
- Badges
- Science topic
- Similar topics
- Biological Science
- Bioecology
- Systems Ecology
- Landscape Ecology
- Connectivity