ASTM D7449/D7449M-22a
(Test Method)Standard Test Method for Measuring Relative Complex Permittivity and Relative Magnetic Permeability of Solid Materials at Microwave Frequencies Using Coaxial Air Line
Standard Test Method for Measuring Relative Complex Permittivity and Relative Magnetic Permeability of Solid Materials at Microwave Frequencies Using Coaxial Air Line
SIGNIFICANCE AND USE
5.1 Design calculations for radio frequency (RF), microwave, and millimetre-wave components require the knowledge of values of complex permittivity and permeability at operating frequencies. This test method is useful for evaluating small experimental batch or continuous production materials used in electromagnetic applications. Use this method to determine complex permittivity only (in non-magnetic materials), or both complex permittivity and permeability simultaneously.
5.2 Relative complex permittivity (relative complex dielectric constant), , is the proportionality factor that relates the electric field to the electric flux density, and which depends on intrinsic material properties such as molecular polarizability, charge mobility, and so forth:
where:
ε0 = permittivity of free space = electric flux density vector, and = electric field vector.
Note 1: In common usage the word “relative” is frequently dropped. The real part of complex relative permittivity ( ) is often referred to as simply relative permittivity, permittivity, or dielectric constant. The imaginary part of complex relative permittivity ( ) is often referred to as the loss factor. In anisotropic media, permittivity is described by a three dimensional tensor.
Note 2: For the purposes of this test method, the media is considered to be isotropic and, therefore, permittivity is a single complex number at each frequency.
5.3 Relative complex permeability, , is the proportionality factor that relates the magnetic flux density to the magnetic field, and which depends on intrinsic material properties such as magnetic moment, domain magnetization, and so forth:
where:
μ0 = permeability of free space, = magnetic flux density vector, and = magnetic field vector.
Note 3: In common usage the word “relative” is frequently dropped. The real part of complex relative permeability ( ) is often referred to as relative perme...
SCOPE
1.1 This test method covers a procedure for determining relative complex permittivity (relative dielectric constant and loss) and relative magnetic permeability of isotropic, reciprocal (non-gyromagnetic) solid materials. If the material is nonmagnetic, it is acceptable to use this procedure to measure permittivity only.
1.2 This measurement method is valid over a frequency range of approximately 1 GHz to over 20 GHz. These limits are not exact and depend on the size of the specimen, the size of coaxial air line used as a specimen holder, and on the applicable frequency range of the network analyzer used to make measurements. The size of specimen dimension is limited by test frequency, intrinsic specimen electromagnetism properties, and the request of algorithm. For a given air line size, the upper frequency is also limited by the onset of higher order modes that invalidate the dominant-mode transmission line model and the lower frequency is limited by the smallest measurable phase shift through a specimen. Being a non-resonant method, the selection of any number of discrete measurement frequencies in a measurement band would be suitable. The coaxial fixture is preferred over rectangular waveguide fixtures when broadband data are desired with a single sample or when only small sample volumes are available, particularly for lower frequency measurements.
1.3 The values stated in either SI units of in inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore each system shall be used independently of the other. Combining values from the two systems is likely to result in non conformance with the standard. The equations shown here assume an e+jωt harmonic time convention.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to ...
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7449/D7449M − 22a
Standard Test Method for
Measuring Relative Complex Permittivity and Relative
Magnetic Permeability of Solid Materials at Microwave
1
Frequencies Using Coaxial Air Line
This standard is issued under the fixed designation D7449/D7449M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 This test method covers a procedure for determining
mine the applicability of regulatory limitations prior to use.
relative complex permittivity (relative dielectric constant and
1.5 This international standard was developed in accor-
loss)andrelativemagneticpermeabilityofisotropic,reciprocal
dance with internationally recognized principles on standard-
(non-gyromagnetic) solid materials. If the material is
ization established in the Decision on Principles for the
nonmagnetic, it is acceptable to use this procedure to measure
Development of International Standards, Guides and Recom-
permittivity only.
mendations issued by the World Trade Organization Technical
1.2 This measurement method is valid over a frequency
Barriers to Trade (TBT) Committee.
range of approximately 1GHz to over 20GHz. These limits
are not exact and depend on the size of the specimen, the size
2. Referenced Documents
of coaxial air line used as a specimen holder, and on the 2
2.1 ASTM Standards:
applicable frequency range of the network analyzer used to
D150Test Methods forAC Loss Characteristics and Permit-
make measurements. The size of specimen dimension is
tivity (Dielectric Constant) of Solid Electrical Insulation
limited by test frequency, intrinsic specimen electromagnetism
D1711Terminology Relating to Electrical Insulation
properties, and the request of algorithm. For a given air line
size, the upper frequency is also limited by the onset of higher
3. Terminology
order modes that invalidate the dominant-mode transmission
3.1 Fordefinitionsoftermsusedinthistestmethod,referto
line model and the lower frequency is limited by the smallest
Terminology D1711.
measurable phase shift through a specimen. Being a non-
3.2 Definitions of Terms Specific to This Standard:
resonant method, the selection of any number of discrete
3.2.1 A list of symbols specific to this test method is given
measurement frequencies in a measurement band would be
in Annex A1.
suitable. The coaxial fixture is preferred over rectangular
3.2.2 calibration, n—a procedure for connecting character-
waveguide fixtures when broadband data are desired with a
ized standard devices to the test ports of a network analyzer to
single sample or when only small sample volumes are
characterize the measurement system’s systematic errors. The
available, particularly for lower frequency measurements.
effects of the systematic errors are then mathematically re-
1.3 The values stated in either SI units of in inch-pound
moved from the indicated measurements. The calibration also
units are to be regarded separately as standard. The values
establishes the mathematical reference plane for the measure-
stated in each system are not necessarily exact equivalents;
ment test ports.
therefore each system shall be used independently of the other.
3.2.2.1 Discussion—Modern network analyzers have this
Combining values from the two systems is likely to result in
capability built in. There are a variety of calibration kits that
non conformance with the standard.The equations shown here
can be used depending on the type of test port. The models
+jωt
assume an e harmonic time convention.
used to predict the measurement response of the calibration
1.4 This standard does not purport to address all of the
devicesdependsonthetypeofcalibrationkit.Mostcalibration
safety concerns, if any, associated with its use. It is the
kitscomewithmediathatcanbeusedtoloadthedefinitionsof
the calibration devices into the network analyzer. Calibration
1
This test method is under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and is the direct responsibility of
2
Subcommittee D09.12 on Electrical Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Sept. 1, 2022. Published October 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2008. Last previous edition approved in 2022 a
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7449/D7449M − 22 D7449/D7449M − 22a
Standard Test Method for
Measuring Relative Complex Permittivity and Relative
Magnetic Permeability of Solid Materials at Microwave
1
Frequencies Using Coaxial Air Line
This standard is issued under the fixed designation D7449/D7449M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers a procedure for determining relative complex permittivity (relative dielectric constant and loss) and
relative magnetic permeability of isotropic, reciprocal (non-gyromagnetic) solid materials. If the material is nonmagnetic, it is
acceptable to use this procedure to measure permittivity only.
1.2 This measurement method is valid over a frequency range of approximately 1 GHz to over 20 GHz. These limits are not exact
and depend on the size of the specimen, the size of coaxial air line used as a specimen holder, and on the applicable frequency
range of the network analyzer used to make measurements. The size of specimen dimension is limited by test frequency, intrinsic
specimen electromagnetism properties, and the request of algorithm. For a given air line size, the upper frequency is also limited
by the onset of higher order modes that invalidate the dominant-mode transmission line model and the lower frequency is limited
by the smallest measurable phase shift through a specimen. Being a non-resonant method, the selection of any number of discrete
measurement frequencies in a measurement band would be suitable. The coaxial fixture is preferred over rectangular waveguide
fixtures when broadband data are desired with a single sample or when only small sample volumes are available, particularly for
lower frequency measurements.
1.3 The values stated in either SI units of in inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore each system shall be used independently of the other. Combining values
+jωt
from the two systems is likely to result in non conformance with the standard. The equations shown here assume an e harmonic
time convention.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
1
This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of Subcommittee
D09.12 on Electrical Tests.
Current edition approved March 15, 2022Sept. 1, 2022. Published April 2022October 2022. Originally approved in 2008. Last previous edition approved in 20142022 as
D7449/D7449M – 14.D7449/D7449M – 22. DOI: 10.1520/D7449_D7449M-22.10.1520/D7449_D7449M-22A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D7449/D7449M − 22a
D150 Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation
D1711 Terminology Relating to Electrical Insulation
3. Terminology
3.1 For definitions of terms used in this test method, refer to Terminology D1711.
3.2 Definitions:
*
3.2.1 relative complex permittivity (relative complex dielectric constant), ε , n—the proportionality factor that relates the electric
r
field to the electric flux density, and which depends on intrinsic material properties such as molecular polarizability, charge
mobility
...
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