Appendix E
425
Theory on Material Measurement
Dielectric Material Measurement
E. Theo
ry on
Ma
teria
l
Me
asur
eme
n
t
Measurement Principle of Dielectric Material
The E4991A uses the measurement technology called the Capacitance Method to measure
relative permittivity. This method calculates relative permittivity from capacitance values
measured with the E4991A by positioning a DUT between the test fixture’s electrodes to
form a condenser. Figure E-2 shows a conceptual diagram using a 16453A text fixture.
Figure E-2
Capacitance Method
Since the capacitor
(see Figure E-2) formed using 16453A has a small capacity
because of its large impedance, the equivalent circuit in Figure E-3 consists of an
equivalent parallel capacitance and an equivalent parallel conductance.
Figure E-3
Loss of Dielectric Material
The admittance Y of the circuit (i) in Figure E-3 is expressed as Equation E-2, and the
complex admittance (
) of the circuit (ii) is expressed as Equation E-3.
indicates a
capacitance when using air as a dielectric material.
Equation E-2
Admittance of Circuit (i)
Equation E-3
Complex Admittance of Circuit (ii)
C
Y
∗
C
0
Y
j
ω
C
j
ω ε∗
r
C
0
=
=
Y
∗
G j
ω
C
p
+
j
ω
C
p
C
0
------
j G
ω
C
0
----------
–
C
0
=
=
Summary of Contents for E4991A
Page 6: ......
Page 24: ...18 Contents ...
Page 80: ...74 Chapter3 Setting Measurement Conditions Averaging Measurement Results ...
Page 220: ...214 Chapter9 Setup and Use of Control Management Functions System Recovery ...
Page 338: ...332 AppendixB Probe Station Connection Kit Option 010 OPEN SHORT LOAD Calibration ...
Page 428: ...422 AppendixD Menu References Menu References ...
Page 482: ...476 AppendixI Messages Wait measuring comp standard ...