Shelley Begley Application Development Engineer Agilent Technologies

1
Shelley BegleyApplication Development
EngineerAgilent Technologies

• Electromagnetic Properties of Materials
  Characterization at Microwave Frequencies and
  Beyond

2
DefinitionsMeasurement Techniques Coaxial
Probe Transmission Line Free-Space Resonant
Cavity Summary

• Agenda

3
Definitions
Loss Tangent?

• Permittivity is a physical quantity that
  describes how an electric field affects and is
  affected by a dielectric medium and is determined
  by the ability of a material to polarize in
  response to an applied electric field, and
  thereby to cancel, partially, the field inside
  the material. Permittivity relates therefore to a
  material's ability to transmit (or "permit") an
  electric fieldThe permittivity of a material is
  usually given relative to that of vacuum, as a
  relative permittivity, (also called dielectric
  constant in some cases).- Wikipedia

Dissipation Factor?
Permittivity!
Dielectric Constant?
Permeability!
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Permittivity and Permeability Definitions
Permittivity (Dielectric Constant)

• interaction of a material in the presence of an
  external electric field.

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Permittivity and Permeability Definitions
Permittivity (Dielectric Constant)

• interaction of a material in the presence of an
  external electric field.

6
Permittivity and Permeability Definitions
Permeability
Permittivity (Dielectric Constant)
interaction of a material in the presence of an
external magnetic field.

• interaction of a material in the presence of an
  external electric field.

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Permittivity and Permeability Definitions
Permeability
Permittivity (Dielectric Constant)
interaction of a material in the presence of an
external magnetic field.

• interaction of a material in the presence of an
  external electric field.

Complex but not Constant!
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Electromagnetic Field Interaction
STORAGE
Magnetic
Electric
Fields
Fields
Permeability
Permittivity
MUT
STORAGE
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Electromagnetic Field Interaction
STORAGE
Magnetic
Electric
Fields
Fields
LOSS
Permeability
Permittivity
MUT
STORAGE
LOSS
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Loss Tangent
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Relaxation Constant t

• t Time required for 1/e of an aligned system to
  return to equilibrium or random state, in
  seconds.

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Techniques
Coaxial Probe
Transmission LIne
Resonant Cavity
Free Space
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Which Technique is Best?
It Depends
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Which Technique is Best?
It Depends on

• Frequency of interest
• Expected value of er and mr
• Required measurement accuracy

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Which Technique is Best?
It Depends on

• Frequency of interest
• Expected value of er and mr
• Required measurement accuracy
• Material properties (i.e., homogeneous,
  isotropic)
• Form of material (i.e., liquid, powder, solid,
  sheet)
• Sample size restrictions

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Which Technique is Best?
It Depends on

• Frequency of interest
• Expected value of er and mr
• Required measurement accuracy
• Material properties (i.e., homogeneous,
  isotropic)
• Form of material (i.e., liquid, powder, solid,
  sheet)
• Sample size restrictions
• Destructive or non-destructive
• Contacting or non-contacting
• Temperature

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Measurement Techniques vs. Frequency and
Material Loss
Loss
High
Coaxial Probe
Transmission line
Medium
Free Space
Resonant Cavity
Low
Frequency
50 MHz
20 GHz
5 GHz
40 GHz
60 GHz
500 GHz
RF
Low frequency
Microwave
Millimeter-wave
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Measurement Techniques vs. Frequency and
Material Loss
Loss
High
Coaxial Probe
Medium
Low
Frequency
50 MHz
20 GHz
5 GHz
40 GHz
60 GHz
500 GHz
RF
Low frequency
Microwave
Millimeter-wave
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Measurement Techniques vs. Frequency and
Material Loss
Loss
High
Coaxial Probe
Medium
Low
Frequency
50 MHz
20 GHz
5 GHz
40 GHz
60 GHz
500 GHz
RF
Low frequency
Microwave
Millimeter-wave
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Measurement Techniques vs. Frequency and
Material Loss
Loss
High
Coaxial Probe
Transmission line
Medium
Free Space
Low
Frequency
50 MHz
20 GHz
5 GHz
40 GHz
60 GHz
500 GHz
RF
Low frequency
Microwave
Millimeter-wave
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Measurement Techniques vs. Frequency and
Material Loss
Loss
High
Coaxial Probe
Transmission line
Medium
Free Space
Low
Frequency
50 MHz
20 GHz
5 GHz
40 GHz
60 GHz
500 GHz
RF
Low frequency
Microwave
Millimeter-wave
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Measurement Techniques vs. Frequency and
Material Loss
Loss
High
Coaxial Probe
Transmission line
Medium
Free Space
Resonant Cavity
Low
Frequency
50 MHz
20 GHz
5 GHz
40 GHz
60 GHz
500 GHz
RF
Low frequency
Microwave
Millimeter-wave
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Coaxial Probe System
Computer (Optional for PNA or ENA-C)
Network Analyzer (or E4991A Impedance Analyzer)
GP-IB or LAN
85070E Dielectric Probe
85070E Software (included in kit)
Calibration is required
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Coaxial Probe

• Material assumptions
• effectively infinite thickness
• non-magnetic
• isotropic
• homogeneous
• no air gaps or bubbles

er
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Three Probe Designs

• High Temperature Probe
• 0.200 20GHz (low end 0.01GHz with impedance
  analyzer)
• Withstands -40 to 200 degrees C
• Survives corrosive chemicals
• Flanged design allows measuring flat surfaced
  solids.

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Three Probe Designs

• Slim Form Probe
• 0.500 50GHz
• Low cost consumable design
• Fits in tight spaces, smaller sample sizes
• For liquids and soft semi-solids only

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Three Probe Designs

• Performance Probe
• Combines rugged high temperature performance with
  high frequency performance, all in one slim
  design.
• 0.500 50GHz
• Withstands -40 to 200 degrees C
• Hermetically sealed on both ends, OK for
  autoclave
• Food grade stainless steel

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Coaxial Probe Example Data
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Coaxial Probe Example Data
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Martini Meter!
Infometrix, Inc.
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Transmission Line System
Computer (Optional for PNA or ENA-C)
Network Analyzer
GPIB or LAN
Sample holder connected between coax cables
Calibration is required
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Transmission Line Sample Holders
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Transmission Line

• Material assumptions
• sample fills fixture cross section
• no air gaps at fixture walls
• flat faces, perpendicular to long axis
• Known thickness gt 20/360 ?

er and mr
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Transmission Free-Space System
Computer (Optional for PNA or ENA-C)
GP-IB or LAN
Calibration is required
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Non-Contacting method for High or Low Temperature
Tests.
Free Space with Furnace
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Transmission Free-Space

• Material assumptions
• Flat parallel faced samples
• Sample in non-reactive region
• Beam spot is contained in sample
• Known thickness gt 20/360 ?

er and mr
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Transmission Example Data
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Resonant Cavity System
Computer (Optional for PNA or ENA-C)
Network Analyzer
GP-IB or LAN
Resonant Cavity Software
Resonant Cavity with sample connected between
ports.
No calibration required
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Resonant Cavity Fixtures
ASTM 2520 Waveguide Resonators
Agilent Split Cylinder Resonator IPC
TM-650-2.5.5.5.13
Split Post Dielectric Resonators from QWED
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Resonant Cavity Technique
empty cavity
fc Resonant Frequency of Empty Cavity fs
Resonant Frequency of Filled Cavity Qc Q of
Empty Cavity Qs Q of Filled Cavity Vs Volume
of Empty Cavity Vc Volume of Sample
Q
c
S21
f
f
c
ASTM 2520
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Resonant Cavity Technique
empty cavity
fc Resonant Frequency of Empty Cavity fs
Resonant Frequency of Filled Cavity Qc Q of
Empty Cavity Qs Q of Filled Cavity Vs Volume
of Empty Cavity Vc Volume of Sample
sample inserted
Q
c
Q
s
S21
f
f
f
s
c
ASTM 2520
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Resonant Cavity Technique
empty cavity
fc Resonant Frequency of Empty Cavity fs
Resonant Frequency of Filled Cavity Qc Q of
Empty Cavity Qs Q of Filled Cavity Vs Volume
of Empty Cavity Vc Volume of Sample
sample inserted
Q
c
Q
s
S21
f
f
f
s
c
ASTM 2520
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Resonant Cavity Technique
empty cavity
fc Resonant Frequency of Empty Cavity fs
Resonant Frequency of Filled Cavity Qc Q of
Empty Cavity Qs Q of Filled Cavity Vs Volume
of Empty Cavity Vc Volume of Sample
sample inserted
Q
c
Q
s
S21
f
f
f
s
c
ASTM 2520
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Resonant Cavity Example Data
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Resonant vs. Broadband Transmission Techniques
Resonant Broadband
Low Loss materials Yes er resolution 10-4 No er resolution 10-2-10-3
Thin Films and Sheets Yes 10GHz sample thickness lt1mm No 10GHz optimum thickness 5-10mm
Calibration Required No Yes
Measurement Frequency Coverage Single Frequency Broadband or Banded
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Summary Technique and Strengths
Coaxial Probe Broadband er Best for liquids, semi-solids
Transmission Line Broadband er mr Best for solids or powders
Transmission Free Space Broadband, mm-wave er mr Non-contacting
Resonant Cavity Single frequency er High accuracy, Best for low loss, or thin samples
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Microwave Dielectric Measurement Solutions
Model Number Model Number Description
85070E 020 030 050 Dielectric Probe Kit High Temperature Probe Slim Form Probe Performance Probe
85071E 100 200 300 E01 E03 E04 Materials Measurement Software Free Space Calibration Reflectivity Software Resonant Cavity Software 75-110GHz Free Space Fixture 2.5GHz Split Post Dielectric Resonator 5GHz Split Post Dielectric Resonator
85072A 10GHz Split Cylinder Resonant Cavity
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For More Information

• Visit our website at
• www.agilent.com/find/materials

For Product Overviews, Application Notes,
Manuals, Quick Quotes, international contact
information
49
For More Information

• Visit our website at
• www.agilent.com/find/materials
• Call our on-line technical support
• 1 800 829-4444

For Product Overviews, Application Notes,
Manuals, Quick Quotes, international contact
information
For personal help for your application, formal
quotes, to get in touch with Agilent field
engineers in your area.
50
References
R N Clarke (Ed.), A Guide to the
Characterisation of DielectricMaterials at RF and
Microwave Frequencies, Published by The
Institute of Measurement Control (UK) NPL,
2003 J. Baker-Jarvis, M.D. Janezic, R.F. Riddle,
R.T. Johnk, P. Kabos, C. Holloway, R.G. Geyer,
C.A. Grosvenor, Measuring the Permittivity and
Permeability of Lossy Materials Solids, Liquids,
Metals, Building Materials, and Negative-Index
Materials, NIST Technical Note 15362005 Test
methods for complex permittivity (Dielectric
Constant) of solid electrical insulating
materials at microwave frequencies and
temperatures to 1650, ASTM Standard D2520,
American Society for Testing and
Materials Janezic M. and Baker-Jarvis J.,
Full-wave Analysis of a Split-Cylinder Resonator
for Nondestructive Permittivity Measurements,
IEEE Transactions on Microwave Theory and
Techniques vol. 47, no. 10, Oct 1999, pg.
2014-2020 J. Krupka , A.P. Gregory, O.C.
Rochard, R.N. Clarke, B. Riddle, J. Baker-Jarvis,
Uncertainty of Complex Permittivity Measurement
by Split-Post Dielectric Resonator Techniques,
Journal of the European Ceramic Society No. 10,
2001, pg. 2673-2676 Basics of Measureing the
Dielectric Properties of Materials. Agilent
application note. 5989-2589EN, April 28, 2005
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Transmission Algorithms
Algorithm Measured S-parameters Output
Nicolson-Ross S11,S21,S12,S22 er and mr
Precision (NIST) S11,S21,S12,S22 er
Fast S21,S12 er
(85071E also has three reflection algorithms)