what is the best material for a radome?

[thiagoyk]

I'm trying to construct an plastic radome for an antenna feed.
At first i tryed to use fiberglass but it distorted the feed's radiation diagram.
Now i'm triyng to use plastic. My fist choice is polycarbonate but i'm having lot of trouble to find an company capable of conforming polycarbonate.
Is there any other plastic recomended for use in radomes? ABS? PETG?

 

[frannk]

You can try polypropylene (PP). It will not be as durable as polycarbonate (PC) or ABS, but it has better electrical properties such as lower loss tangent and lower dielectric constant. Sonoco is a major supplier of various PP. The best thing to do is to redesign your antenna for a specific radome material that will meet your environmental requirements.

 

[sergio mariotti]

GoreTex is perhaps the best one, extremally transparent to RF power, resistant to extreme weather conditions and minimize the water condensation inside the enveloped mirror, but it's very expensive.
PE (Polyethilene) is also extremally low loss and very anisotropic, but to be weather resistant a thick and black sheet should be used.
Black colour is important to be resistant to weather, especially sun radiation.

 

[mr_ghz]

Hi thiagoyk

For which frequency you will use the radome? - For higher microwave bands (10GHz and higher) it is necessary to adapt the radome to the frequency. The easiest way is to make the microwave power travelling in a 90 degree angle through the radome and make it lambda/2 thick (lambda means the wavelength inside the radome-material at the specified frequency!)
I have used polycarbonate with good results at 24GHz. ABS is also possible, but the er is not as constant as with PC.

Regards
mr_ghz

 

[thiagoyk]

i'm working at a much lower frequency, 2GHz.
Finally i found a company that will produce the polycabonate radome.
I will run some tests when the radome is ready, but a think that at this frequency it will not show much problems.
My main concern is the UV resistance. I think i will have to replace de radome within 3 years aprox. just to be safe.