Dielectric constant of air with temperature change

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SUMMARY

The dielectric constant of air varies with temperature, and understanding this relationship is crucial for accurate phase measurements in antenna systems. The formula C=Ae/d can be utilized to calculate capacitance, where 'e' represents the dielectric constant. At 1 GHz, a temperature change from 25°C to 15°C will affect the phase delta between antennas positioned at different distances. The relative permittivity of air is influenced by electric susceptibility, which has been documented in various publications regarding its temperature dependence.

PREREQUISITES
  • Understanding of dielectric constants and their relevance in electromagnetic theory.
  • Familiarity with the formula C=Ae/d for capacitance calculations.
  • Knowledge of phase measurements in antenna systems.
  • Basic principles of electric susceptibility and its relation to permittivity.
NEXT STEPS
  • Research the relationship between temperature and dielectric constant in air.
  • Study the impact of electric susceptibility on relative permittivity.
  • Explore publications discussing dielectric properties of gases at varying temperatures.
  • Learn about phase measurement techniques in antenna systems and their dependencies on environmental factors.
USEFUL FOR

Electrical engineers, physicists, and researchers involved in antenna design and electromagnetic theory, particularly those focusing on the effects of environmental conditions on signal propagation.

Antenna_Ed
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I'm looking to see how much the dielectric constant of air will change mostly as a function or air temperature.

Is there a formula that outputs air dielectric as a function of temperature or atmospheric pressure?
 
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If using a capacitor you might be able to use C=Ae/d but I really don’t understand your question fully
 
Let's pretend I have a source antenna outputting a 1 GHz. I have two receive antennas on the main lobe. One is 10 meters away and the other is 11 meters away. I do my measurement at 25 C. I'm going to get some phase delta between these two antennas.

Now if the temp is 15 C when I make the measurement, what will the phase delta be? I'm ignoring everything else at the moment and only care about the effect of air. If I knew the dielectric I can compute the velocity factor and know the magnitude of change.
 
Intuitively, I would expect permittivity to increase with an increase in temperature. The relative permittivity is directly related to electric susceptibility, and I believe there are a number of publications that exist discussing the subject of the dependence on electric susceptibility of air with temperature. I haven't done a lot of research on the subject, but I would start there.
 

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