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Appendix E
Theory on Material Measurement
Dielectric Material Measurement
Dielectric Material Measurement
If your E4991A has Option 002 installed, it is possible to measure the relative permittivity
of a solid dielectric material taking the shape of a board. Permittivity here refers to the ease
of storing energy in an electric field.
Definition of Permittivity
The application of an alternating-current electric field to a dielectric material causes some
dielectric loss and a delay in the dielectric response to the electric field. Permittivity in an
alternating-current electric field is defined as complex relative permittivity (
) (see
Equation E-1). The real component of complex relative permittivity (
) represents the
amount of energy stored in the dielectric material from the alternating current electric field.
On the other hand, the imaginary component (
) indicates energy loss to the alternating
current electric field.
Equation E-1
Definition of Complex Relative Permittivity
As shown in Figure E-1, complex relative permittivity can be expressed in a vector
diagram. The dielectric loss factor (D) of a dielectric material is expressed as a dielectric
loss tangent (tan
δ
), which is the ratio of the imaginary component (
) to the real
component (
) of complex relative permittivity.
Figure E-1
Vector Diagram of Complex Relative Permittivity and Dielectric Loss Tangent
NOTE
Dielectric material measurement generally implies the measurement of its relative
permittivity.
ε∗
r
ε
'
r
ε″
r
ε∗
r
ε
'
r
j
ε
''
r
–
=
ε″
r
ε
'
r
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 ...
