What material( liquid/glue) is good for an RF absorber?
Im designing an absorber and finding what material in liquid or glue that is suitable for pasting onto the surface of microstrip. Does anyone know?
Thank you,
Best,
As RF absorbers, typically any resistive powder works. I have used fine iron powder mixed with Epoxy glue, the most you can mix in. I have also used soot powder in Epoxy, to make quite good microwave attenuators and terminations.
Emerson-Cuming company offers EM absorbers as well as powders and glues.
Could you check if this is the appropriate one
Emerson & Cuming Microwave Products -- ECCOSORB CRS
Moreover, I couldn't find the powder, is it necessary to mix the iron powder and the glue to paste the the surface?
Yes, sure, by mixing the iron or soot powder into Epoxy you get a well-absorbing glue. You can also pour it to a form to get an absorbing body, or a layer or film.
I have used iron powder and soot many years ago, I cannot advise on a source now. The "secret" of all absorbers is that they have a conductivity close to 50 Ohms if applied in 50-Ohm structures, or, 377 Ohms if applied in a "free space" or in waveguides.