Determination electric and magnetic characteristic of materials

1
Determination electric and magnetic
characteristic of materials

• Vasa Radonic
• Nelu Bla
• Ljiljana ivanov
• CIMC, Novi Sad

2
Outline

• Introduction
• Overview of measurement techniques
• Permittivity
• Permeability
• Different methods for characterization of
  materials
• Explanation
• Result
• Advantage/Disadvantage
• Future plans

3
Introduction
4
Introduction

• Dielectric and magnetic properties of materials
  and their frequency and temperature dependence
  give valuable information
• Complex permeability and permittivity are the
  critical parameters for the optimization
• The knowledge of these parameters may be applied
  in circuit design and wave transmission
  calculations
• Various time- and frequency-domain methods have
  been developed to facilitate measurement of the
  dielectric and magnetic properties

5
Introduction

• In the most cases considering measurement
  materials, the following characteristics of
  sample holders are important
• Operation range of frequency
• Suitability for the sample temperature control
• Relatively small sample size
• Compatibility with FD and TD techniques
• Applicability to measurement in situ, etc.
• Standard configurations that are widely used for
  dielectric and magnetic measurement

6
Permeability measurements

• Methods
• Principle
• Equations

7
Permeability measurements

• Describes the interaction of a material with a
  magnetic field
• The ratio of magnetic flux density B to the
  applied magnetizing field H
• Bµ0µr H
• Many methods for determination of magnetic
  properties exist
• RF and MW measurements of µr are best done with
  torodial cores
• The magnetic toroid in a coaxial (short) holder
  presents the best solution

8
Inductance method

• Inductance method
• µ of sample is obtain by measuring the Z
  (inductance)
• Differences between a coil wound around the
  toroidal sample and one wound around a
  non-magnetic blank (without sample)

Inductor with toroidal sample
Equivalent circuit
Ls
Rs
9
Inductance method
F19
F14
Inductor without sample
Inductor with sample
Low-capacitance winding
10
Inductance method
HP 4191A
Impedance analyzer HP4191A HP4194A Measurement
of Z Frequency range 10kHz-1GHz
11
Inductance method
12
Inductance method
13
Inductance method
14
Inductance method
15
Inductance method
16
Inductance method

• Advantages
• Simple for realization
• For frequency below 100 MHz
• Disadvantages
• Hand made inductors
• Results depend of how an inductors are made
• Control of the turns is difficult
• Cross section has to be small
• Low-capacitance windings are used up to 500MHz

17
Short Coaxial Line method

• Commonly used to measure in a wide frequency
  range
• The high frequency permeability of tested sample
  was obtained by measuring the input differences
  between the coaxial sample holder loaded with and
  without toroidal sample
• When the sample is inserted in holder, the whole
  system is completely closed
• Standard APC-7 holders are used

18
Short Coaxial Line method

• Construction of holder creates one toroidal turn
  around the sample
• Magnetic flux
• Equivalent circuit
• Complex susceptibility is

L
R
19
Short Coaxial Line method

• Measured complex impedance
• Permeability
• Vector network analyzer Agilent Technology E5071B
• Frequency range 300kHz - 1GHz

20
Short Coaxial Line method
21
Short Coaxial Line method
F19
F19
F14
F14
Very good arrangement with catalogue
characteristic are obtained in a wide frequency
range
22
Short Coaxial Line method
In order to extend frequency range up to 2GHz new
holder is constructed
F19
F14
23
Short Coaxial Line method

• Advantages
• Wide frequency range (300kHz-2GHz)
• It can be implemented for powders and liquids
• Disadvantages
• Small dimensions of sample
• Main disadvantage is a closed system of
  measurement
• Temperature control.

24
Permeability measurements

• Future activity
• Developing the user-friendly program for computer
  control and post-processing
• Characterization of metamaterials
• Characterization of magnetic powders and liquids

25
Permittivity measurements

• Methods
• Principle
• Equations

26
Permittivity measurements

• Dielectric properties of materials and their
  frequency and temperature dependence are great
  importance in many applications
• An electrical field in a dielectric material
  produce in general a displacement current and the
  ohmic current
• Many of methods for permittivity determination
  are based on measurement of capacitance
• The parallel plate capacitor method is commonly
  used in measurements of permittivity
• For RF and MW frequency range coaxial methods

27
Permittivity measurements

• Dielectric properties of materials and their
  frequency and temperature dependence are great
  importance in many applications
• An electrical field in a dielectric material
  produce in general a displacement current and the
  ohmic current
• Many of methods for permittivity determination
  are based on measurement of capacitance
• The parallel plate capacitor method is commonly
  used in measurements of permittivity
• For RF and MW frequency range coaxial methods

28
Permittivity measurements

• Dielectric properties of materials and their
  frequency and temperature dependence are great
  importance in many applications
• An electrical field in a dielectric material
  produce in general a displacement current and the
  ohmic current
• Many of methods for permittivity determination
  are based on measurement of capacitance
• The parallel plate capacitor method is commonly
  used in measurements of permittivity
• For RF and MW frequency range coaxial methods

29
Measurement method

• Parallel plate method
• Good for smaller diameter of parallel plate
  capacitors
• Uniform field
• Equivalent circuit

30
Parallel plate method

• Permittivity is obtain from the measured of
  capacitance
• The inverse of Q gives tand as
• Characteristic impedance, admittance, resistance,
  etc

LCZ meter Frequency range 1kHz - 1MHz
LTCC tapes and Capacitor
31
Parallel plate method
32
Parallel plate method
Simple program for computer control Frequency
range 1kHz - 1MHz
33
Parallel plate method

• Advantages
• Simple calculation
• Does not need a sample holder
• Disadvantages
• Low-frequency method
• Realization of contacts

34
Coaxial line method

• Coaxial TEM structures operate in a wide
  frequency range (100MHz to few GHz)

35
Coaxial line method

• Lumped capacitive method
• The configuration is particularly suitable for
  measuring the permittivity of liquid, biological
  sample or semisolid materials
• This configuration required the smallest sample
  size
• The total capacitance
• Conditions

36
Coaxial line method

• The relative dielectric constant and loss factor
  are calculated from reflection coefficient
• The method is particularly suitable for
  measurement of the biological substance, as well
  as thin plate of semiconductor and magnetic
  material.
• Frequency range of 0.1-10GHz can be covered by
  only one sample holder

37
Permittivity measurements

• Future activity
• Improve the user-friendly program for computer
  control and post-processing
• Improve of sample holder characteristics
• Characterization of liquid
• Characterization of metamaterials