RF transparent material

[anjalina]

Hello Sir/ Ma'am,

Currently we are using 433.92 MHz RF frequency, with the covering of rubber sleeve(Heat shrinkable) on the transmitter device. For reference please go through below link:

• https://robu.in/product/heat-shrink...PoobT5ub6CICkuDJoR3rXAUVC8Gsz99gaAtQxEALw_wcB

We are expecting our range of 12 to 15 meter between TX and Rx, but we get the range of 6 to 7 m by using current sleeve. So please suggest the best sleeve material to get appropriate range according to our requirements.

Note: The sleeve material should be heat shrinkable with less diameter(about 28 mm) , thickness should be less than 0.5 mm, black colour sleeve without glossy look.

 

[dick_freebird]

Your links do not lead to any info on RF attenuation.

But I think it's unlikely that a piece of heat-shrink
is responsible for 3dB power loss. You will have to
look harder, for where to pin the blame.

Reality vs expectations problem, is not necessarily
reality's fault. There's that.

 

[RCinFLA]

When dealing with black stuff you alway have to be suspect of carbon black content.

One easy way to check non-metalic material is place it in a microwave oven and increment heating time up from a few seconds to see if material gets warm. The freq is 2.4 GHz but it is good enough in most cases to see if material is RF lossy.

 

[volker@muehlhaus]

I suspect the dielectric material directly at the PCB antenna might de-tune the antenna resonance. So even a lossless dielectric can have an effect, if too close.

 

[anjalina]

If we can't use the dielectric material near to antenna then how we can cover our antenna to get minimum RF loss and maximum TX range. We can't use the enclosure because our device is wearable.
So please suggest the alternate solution for our query.

 

[volker@muehlhaus]

I understand that you were looking for a cheap simple solution.

The solution that my clients use in these cases: design an antenna to operate in that final environment. Which means tuning the antenna to frequency for that packaged situation. Not trivial, but a proper solution. For wearables, you also need to consider the effect of the body.

 

[anjalina]

Yes, we aware about the effect of the body is also affected on the RF range. Please provide the best suitable alternative solution for that.

 

[volker@muehlhaus]

This is too complex for free forum support. If you have a budget for consulting services...

[Moderator note: Sending private message through Edaboard is permitted (or Start Conversation)]

 

[dick_freebird]

Detuning and attenuation may have the same
effect at the remote terminal, but could want
different solutions.

You could obtain some clear heat-shrink and
do a simple substitution to test the carbon-
loading hypothesis. Not clear to me whether
you also tested a radio with the only difference
being the presence / absence of that one bit
of plastic.

Do not expect a get-it-done answer / prescription,
other than a careful series of cut-and-try tests.
Even somebody else's similar anecdote depends
on too many invisible details of implementation.