Re-Evaluating Radiated Emissions and Exposure for Potted Transmitter Housings
Encapsulating transmitters alters dielectric loading, detuning antennas and shifting RF exposure boundaries, demanding re-evaluation of emissions and SAR compliance.
Silicone Encapsulant
Meaning
Elastomeric materials applied to circuit assemblies offer excellent moisture protection and thermal stability over a wide temperature range. Utilizing a silicone encapsulant provides a soft, stress-relieving barrier that cushions delicate components against vibration.
Material Property
Low modulus characteristics ensure that the cured gel or elastomer does not exert excessive force on fine wire bonds. While a silicone encapsulant lacks the mechanical strength of epoxy resins, its superior flexibility prevents cracking during thermal cycles. This elasticity is maintained across an operating window extending from sub-zero temperatures to high limits.
Thermal Performance
Power modules and automotive sensors rely on these compounds to withstand intense heat without degrading. The silicone encapsulant maintains its electrical insulation properties even when exposed to high temperature spikes. Its structural stability ensures that the material does not become brittle or lose adhesion over the product lifecycle, which is essential for long-term outdoor deployment in harsh environments.
Application Technique
Dispensing the liquid material requires precise control of the mixing ratio in two-part systems. To apply the silicone encapsulant, automated nozzles dispense the mixture directly into the housing, where it flows around the components. Degassing under vacuum is often necessary to eliminate bubbles before the curing process begins.