The facts about Ferrite Tiles
As well as being a commercial supplier we also like to share our knowledge for people who want to know. We have put together unbiased fact sheets for each of the products we supply.
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The application of these tiles is to line shielded chambers so that more accurate radiated EMC may be facilitated.
Ferrite tiles are mainly made from Iron & Nickel powders which are sintered (compacted with great heat and force) and then precision ground for dimensional accuracy.
The ‘return loss’ performance of ferrite tiles differs little from manufacturer to manufacture and all have the following ‘normal incidence’ characteristics:
All flat absorber have significant performance reduction (decay) when the energy (Radio wave) hits the ferrite tile at ‘off normal’ angles. The practical effects of this are apparent if the ceiling of a compact chamber is too low, an oblique angle of incidence reflection between Equipment under test and the receive antenna (emissions) will cause chamber performance loss.
When chambers become larger the angle of incidence improves and the chamber becomes better, this is why 3m and 10m chambers have a minimum useable size. It is important to have an ‘RF back reflector’ behind the ferrite tiles, a large gap to the shield will cause performance loss.
Ferrite tiles are about the same weight as steel so a 6.5mm ferrite tile has about 30Kg/m2 of weight (+ boards and fixings) so this weight should be taken into consideration in chamber weight loadings and structural strength.
Some tile come with a hole in the centre which can be 6 or 10mm, this hole has no effect on the performance.
Some companies screw the tiles into position, some glue into position whilst others build into panels and screw into position.
