36 | Keysight | E4991B Impedance Analyzer - Data Sheet
Typical Effects of Temperature Change on Permittivity
Measurement Accuracy
When the temperature at the test port (7-mm connector) of the high temperature cable
changes more than 5 °C from the calibration temperature, the typical permittivity
measurement accuracy involving temperature dependence effects (errors) is applied.
The typical permittivity accuracy is represented by the sum of error due to temperature
coefficient (Tc), hysteresis error (Tc × ΔTmax) and the accuracy at 23 °C ± 5 °C.
Typical accuracy of permittivity parameters:
Δ [´r m
[´r m
[r´ accuracy =
:
± (E[ + Ef + Eg) [%]
‘
Loss tangent accuracy of [ (= Δtand) :
(E[ + Ef + Eg )
±
100
where,
E[
Ef
= Permittivity measurement accuracy at 23 °C ± 5 °C
= Tc × ΔT × 100
Eg
= Tc × ΔTmax × 0.3 × 100
Tc [°C-1] = K1 + K2 + K3
See Figure 54 through Figure 56 for the calculated value of Tc
without temperature compensation
K1 [°C-1] = 1 × 10-6 × (60 + 150 × ƒ)
K2 [°C-1] =
´
1
3 × 10-6 × (1 + 10 × ƒ) ×
×
+10 × ƒ
[
r m
2
t
f
1–
fo
K3 [°C-1] =
1
5 × 10-3 × (0.3 + 3 × ƒ) ×
[´r m
1
×
+10 × ƒ
2
t
f
1–
fo
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