Meaning
Physical metric defines how the dielectric constant of a material changes in response to variations in temperature. Knowing the thermal coefficient of permittivity is necessary when selecting polymers for high-frequency radomes that operate across wide environmental extremes. This measurement establishes the boundary for the phase stability of the radar module in winter and summer.
Temperature Sensitivity
Outdoor wireless and radar sensors must maintain their performance from sub-zero winter temperatures to high summer heat. The thermal coefficient of permittivity determines how much the material properties will shift during these temperature sweeps. This shift is particularly pronounced in polymers that absorb moisture or undergo phase transitions.
Permittivity Drift
A high coefficient value indicates that the dielectric constant will rise or fall as the temperature changes. This thermal coefficient of permittivity causes the electrical thickness of the radome to drift away from the half-wavelength design target. This drift creates unexpected signal reflections that can degrade the sensor radiation pattern.
Radar Performance
Driver assistance systems require stable antenna characteristics to ensure correct angle calculations. If the radome’s properties change due to temperature fluctuations, the resulting phase errors can cause a shift in the boresight angle. This shift introduces errors in the estimated position of targets in the road, which can affect the operation of emergency braking systems.
Choosing materials with a low coefficient is necessary to guarantee reliable radar tracking under all weather conditions.
