Synthesis and Experimental Characterization of the Potting Material to Reduce the Radio Frequency Signal Attenuation

Abstract

Radio frequency transmitting equipment used in the automotive industry, such as RADAR, GSM, GPS, and Bluetooth need to be encapsulated to protect them from variable operating conditions such as temperature fluctuation, dampness, vibration, and external environments. The encapsulation of these devices with polymeric hard potting leads to the attenuation of specific signal strength. In the present investigation, epoxy resin incorporated with various concentrations of hollow glass microspheres was prepared in order to reduce the effective thickness of solid epoxy material on top of the radio frequency transmitting devices and therefore reduce the signal attenuation. This investigation was related to epoxy composite preparation and enhancement of the signal transmission of potted radio frequency (RF) transmitting devices typically operating between 0.1 to 30 GHz. Morphology, structural characterization and thermal properties, of the prepared composites, were identified using a scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). Bluetooth Low Energy (BLE) analyzer and NRF connect application were employed to measure the signal range. The maximum signal range with prepared potting composites was found to be between 12-14 meters, whereas hard epoxy potting was found to be between 3-5 meters. The specific gravity and hardness of the epoxy-filled hollow glass microsphere (HGM) composites were investigated. The result signifies density and hardness of the composites decreased with the increase of HGB volume. Keywords: Bluetooth, Characterization, Epoxy Potting, Encapsulation, Hollow Glass Microsphere, Potting, Radio Frequency, Signal Attenuation, TCU