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RF diffuser

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Aalto.png This page was part of an Aalto University course 3D Printing of Open Source Hardware for Science

Please leave comments using the discussion tab. The course runs in the Fall semester 2017. It is not open edit.


Rendered CAD model

Designer[edit]

Jaakko Haarla' Department of Electronics and Nanoengineering, Aalto University


Project[edit]

In antenna measurements, it is important to only measure the line of sight path. Normal room has lots of reflections from walls which leads to strong multipath effect. These can be seen in strong variations in measured response as a function of antenna location. In normal measurement setup this problem is solved by coating whole measurement room with RF absorbers. If absorbers are not available these strong reflections need to be dealt with some other way.

In audio applications these diffusers have been used to scatter sound waves and to reduce echoes to noise. RF diffuser would operate with same principles but with EM-waves and at much higher frequencies.


Model[edit]

Concept

RF diffuser consists of a defined base block and rectangular boxes with fixed base dimensions and random height on top of it. Random heights of the structure will reflect plane waves back so that they sum up incoherently.

CAD model is fully parameterized, so used frequency range and size can be tuned to suite users needs.

RF diffuser design files.

Bill of Materials

  • RF diffuser block
  • Conductive coating material

Estimated Cost

3.15€ (printed parts) (PLA price 25€/kg)

N/A € (metal/conductive coating)


Total: 3,15€ + coating for assembled element


Estimated Savings

N/A since similar products are not commercially available.


Directions

1.) Download, open OpenSCAD file, and tune the parameters if needed.

2.) Render the model to randomize the pattern. (CAD model creates random structure for each rendering.)

3.) Print RF diffusers. Repeat steps 2.) and 3.) until you have enough elements.

4.) Coat 3D printed parts with conducting material e.g. copper.


Gallery[edit]

CAD model and printed part
Rendered CAD model  
RF diffuser  
RF diffuser  
RF diffuser  
CST RCS simulation at 10 GHz