A medium is transparent with respect to one or many bands of em waves. That can be studied by absorption experiment. What physical property lies behind this ? How this is related to permittivity or permeability of the medium ?
Regards
Nityananda Das
Hi
Hi when permittivity and permeability is more for a material its wave attenuation would be higher.. Becasue when a material is mire in permeability and permittivity it may affect the electrical and magnetic compoments of incoming microwave.... Hence permittivity and permeability are directly proportion to EM attention....
Pkease go through this paper
See my RG site. In that yiu can find papers regarding this
Here some uploading issue....
Best
Dear Arun Prakash
It's obviously true that as the permittivity and permeability of a medium is higher the attenuation increases. But what is the relationship between permittivity and permeability and frequency ?
Regards
Nityananda Das
Actually
Permeability related to magnetic and permittivity related to electrical charge conduction.....
This will be reduced with increase of frequency....
Permittivity and permeability is inversely proportional to frequency
Best
Dear Arun Prakash
Thank you for your answer. But I thik there is no straight forward relationship between permittivity and permeability with frequency.
I don't know whether there is any universal relationship or not.
Regards
Nityananda Das
Hi
Actually i have conducted so many trials in a polymer nanocomposite..... I found that at lower frequency the permittivity will increase (upto 100Hz) when frequency above 300 Hz the permittivity goes diwn and further it will very lower value when frequency is more than 1KHz....you go through my papers in RG....
About permeability when frequency increases the domain alignment get reduces and also inherent temperature raise would reduce the permeability.
Nityananda Das
Permittivity is related to a material's ability to store an electric field inside the medium. Electromagnetically transparent medium means either that is vacuum, air or any other engineered medium with relative permittivity 1 and negligible electrical conductivity. In general, there is no natural medium except air that is purely transparent to an electric field over a broad frequency spectrum.
When an electric field passes through a medium, randomly oriented polar molecules try to orient them along the incident electric field. The more it's difficult to orient polar molecules along incident electric field, higher the permittivity of the material (at a particular frequency).
Absorption in solid non-magnetic materials is usually determined by imaginary part of a dielectric constant (i.e. permittivity), and the dielectric constant in turn depends on frequency in a complex way depending on the material. See, for example, here:
http://www.physics.usu.edu/Wheeler/EM/Notes/EMNotes11FreqDepPermittivity.pdf
You can ignore permeability for non-magnetic materials.
Also, it may be useful to have a look at the previous discussion: https://www.researchgate.net/post/Does_the_dielectric_constant_increase_with_increasing_frequency
Please see the link below:
https://www.ijeat.org/wp-content/uploads/papers/v3i5/E3058063514.pdf
Best regards
Look at the wikipedia page on dielectric. The relation between loss, frequency and dielectric constant is described by the Debye relationship and its variants. There are similar relationships for magnetic losses.
- Badges
- Science topic
- Similar topics
- Filing