QUESTION

Question

To withstand harsh environmental conditions in certain applications the entire pcb needs to be covered with resin. Does somebody have experience with covered antenna? Are there special antennas available for such cases? Is there a recommondation for e specific type of resin? What else needs to be considered?

I’m very thankful for information on this topic

Best regards,

Thomas

Answer 1

Hi Thomas,

We have had customers do this successfully in the past. Different resins have different (DC) electrical properties. However, the electrical characteristics of the potting compound will have widely varying effects dependent upon frequency. Can you share which antennas you are considering and which frequencies?

Many Thanks

Steve

Answer 2

Hi Steve

Thank you for your answer. We are considering using SMD Antennas like Antenova Integra or similar. The Antenna is used for NB-IoT / Cat-M1 technology.  

We want to use freuqency bands: B3, B8 and B20

Thank you

Thomas

Comments

Hi Thomas,

We have found, especially in sub-GHz bands, that generally Silicon potting has less of an effect than resins. I would recommend something like Dow Corning Sylgard 170 if this is sufficiently protective. Integra is typically a good choice for this type of application, depending on how your PCB and device are otherwise configured. Do you have an idea of your PCB dimensions and will you need antennas for other protocols (e.g. WiFi, GNSS etc.)

Many Thanks

Steve

Answer 3

Hi Steve,

The size of the PCB will be 64mm x 36mm - there will be no other antenna for another protocol.

In terms of process of development: would you recommend to design the system as it would be without potting and then tune the antenna after applying the protection material by choosing the components of the matching circuit? Or can the potting be anticipated before?

Thank you and regards,

Thomas