Albatross Projects - hybrid absorbers

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technologies

hybrid absorbers

ferrite absorbers

pyramidal absorbers

Hybrid absorbers consist of a matched pyramidal absorber on top of a ferrite absorber and are today the most used type of EMC absorber. Without ferrite absorbers the world of EMC Test Sites would look very different today. Since their introduction in the 1980’s, these absorbers have reduced the size, i.e. the volume of EMC Test Sites by more than 50%.

design

Hybrid absorbers consist of several parts. The two major parts are the ferrite absorber tile, typically 100 x 100 x 6mm and the matched resistive absorber pyramid. The typical construction of the hybrid absorber used by Albatross projects and its corresponding equivalent circuit diagram is shown in picture 1.

Of major importance in designing hybrid absorbers is the installation method of the ferrite tile. In principle two methods are available on the market today.

Method 1

Ferrites tile fitted directly onto on a metal surface (as shown on picture 1); this method ensures the maximum performance at 30MHz

Method 2

A resistive (dielectric) layer e. g. wood, fitted between the ferrite tile and metal surface (also referred to as the double layer method). This leads to a shift in the resonance with a better return loss to the frequency range between a few hundreds of MHz and 1GHz. However, this method reduces the performance at 30MHz and makes the matching of the ferrite tile to the foam part in the GHz range difficult

matching

RF absorbers can be easily installed by the "hook" method.

The matching design used by Albatross Projects is a unique feature, we refer to as the Matching Layer Technique (MLT). The ferrite tiles and matched foam absorber are mass produced items, both having tolerances of their intrinsic electrical values. When monitoring the bandwidth of these individual values, the thickness of the matching layer is defined. This layer is then factory bonded to the back of the foam absorber thus optimising the component matching.

The distance between the ferrite and pyramid absorber is a critical calculation for the hybrid absorber performance, the Albatross Projects MLT method ensures conformity when the physical conjunction of the two major components takes place during the installation process. The matched foam absorbers are fitted to the ferrite tiles by ‘hanging’ them on fixation discs pre fitted during the ferrite tile installation. (See adjoining picture: “Easy Hook” Absorber Installation) This maintains our principle of modular chambers, a short installation time and simple replacement of absorbers items.

data

Standard Colour	Light blue or unpainted with white cap
Base dimensions VHY	0.60m x 0.60m
Base dimensions Ferrite	0.10m x 0.10m
Maximum service temperature	90°C for MP-part, 50°C for F-part
Power handling capability	1.5 kW/m² or 600V/m
Fire retardant classification	DIN 4102 Class B2
	NF P92-501 Class M2
	ISO 3582
	NRL 8093 Tests 1, 2 & 3
Absorber Type	VHY-12, VHY-18, VHY-30, VHY-40
Weight	9 kg/m² 10 kg/m²12 kg/m² 25 kg/m²
Height	325mm 457mm 774mm 996mm
Weight, Ferrite	30kg/m²

For further information, please contact us.

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