Atec Agilent-16047A - Manual (Page 43)

16451B Dielectric Test Fixture
Terminal Connector: 4-Terminal Pair, BNC
Dimension (approx.): See page 40
Cable Length (approx.):
0.8 m(from connector to electrodes)
Weight (approx.): 3700 g
Measurement Accuracy
(supplemental performance characteristics):
f: measured frequency [Hz] f
≤
30MHz
ε ’
rm
: measured permittivity
tan δ : measured dissipation factor
ε
0
: permittivity of air 8.854 × 10 -12 [F/m]
d: diameter of electrode {A,B}
t: thickness of material [mm]
Az: Impedance measurement error of instrument
Ad: D measurement error of instrument
The material is assumed to be ideally flat.
The above equation is applicable for electrodes A and
B when using the contacting electrode method.
38
Up to 110 MHz (4-Terminal Pair) Material
Description: The 16451B is used to evaluate the dielec-
tric constant of solid dielectric materials accurately, and
complies with ASTM D150. The 16451B employs the par-
allel plate method, which sandwiches the material
between two electrodes to form a capacitor. LCR meter or
an Impedance Analyzer is then used to measure the
capacitance created from the fixture. A measurement
block diagram of the parallel plate method is shown
below:
Notice the stray capacitance, which is formed on the test
material as shown in the figure above. The guard elec-
trode helps to eliminate the stray capacitance at the edge
of the electrode.
Basic Measurement Accuracy (including the 4294A):
Parallel plate method
Typical Permittivity ( ε r') Measurement Accuracy:
4294A with 16451B
Typical Loss Tangent (tan δ ) Measurement Accuracy:
ε
'
r
accuracy ( )
ε
'
r m
∆
ε
'
r m
A
Z
+ 0.04 f 2
ε
'
rm
ε
0
+
π
2
d
t
2
100 (
ε
'
rm
– 1)
(
ε
'
rm
– )
t
0.01
[%]
π
2
d
t
2
E a = 0.005
+
0.0004 f 2
ε
'
r m
ε
0
E b =
100
tan δ
ε
' r m
∆ ε
' r m
tan δ < 0.1 :
ε * Loss Tangent Accuracy ( ∆ tan δ)
tan δ < 0.1 : Ad + Ea + Eb
4294A Measurement Settings;
1. Osc level : 500 mV
2. BW: 5
3. Adapter setup : 1 m
4. Compensation : Open, short and load