SIST EN 61338-1-3:2002

• Abstract:

  Describes the measurement methods of the complex relative permittivity of dielectric resonator materials at microwave frequencies by means of the dielectric rod resonator method short-circuited at both ends by parallel conducting plates.

• Status: Published
• Publication Date: 31-Aug-2002
• ICS: 31.140 - Piezoelectric devices
• ICS: 33.120.10 - Coaxial cables. Waveguides
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Sep-2002
• Due Date: 01-Sep-2002
• Completion Date: 01-Sep-2002
• Ref Project: EN 61338-1-3:2000 - Waveguide type dielectric resonators - Part 1-3: General information and test conditions - Measurement method of complex relative permittivity for dielectric resonator materials at microwave frequency

• Referred By: SIST EN 61338-1-5:2015 - Waveguide type dielectric resonators - Part 1-5: General information and test conditions - Measurement method of conductivity at interface between conductor layer and dielectric substrate at microwave frequency
• Effective Date: 03-Feb-2026
• Referred By: SIST EN 61338-2:2005 - Waveguide type dielectric resonators -- Part 2: Guidelines for oscillator and filter applications
• Effective Date: 03-Feb-2026
• Referred By: SIST EN IEC 63185:2021 - Measurement of the complex permittivity for low-loss dielectric substrates balanced-type circular disk resonator method (IEC 63185:2020)
• Effective Date: 03-Feb-2026
• Referred By: SIST EN 61338-1-4:2006 - Waveguide type dielectric resonators -- Part 1-4: General information and test conditions - Measurement method of complex relative permittivity for dielectric resonator materials at millimetre-wave frequency
• Effective Date: 03-Feb-2026
• Referred By: SIST EN 61338-1:2005 - Waveguide type dielectric resonators -- Part 1: Generic specification
• Effective Date: 03-Feb-2026

SIST EN 61338-1-3:2002 is the Slovenian standard identical to EN 61338-1-3:2000, based on IEC 61338-1-3:1999 from the International Electrotechnical Commission (IEC). It specifies a dielectric rod resonator method for measuring the complex relative permittivity of dielectric resonator materials at microwave frequencies. The document focuses on the properties needed for microwave resonator and filter materials - ε′, tan δ, TCF, and the temperature dependence of tan δ - for isotropic, homogeneous materials.

What does SIST EN 61338-1-3:2002 specify?

SIST EN 61338-1-3:2002 specifies how to measure microwave dielectric properties with a dielectric rod resonator short-circuited at both ends by parallel conducting plates. Clause 1 gives the scope and object, Clauses 2 to 7 cover the parameters, theory, specimen preparation, equipment, procedure, and error estimation, and Annex A is a bibliography.

Annex	What it covers
Annex A	Bibliography

The scope is practical and measurement-oriented. It sets out the method, the quantities to be measured, and the assumptions used in the calculations, so users can prepare specimens and interpret resonance data consistently.

What are the key requirements of SIST EN 61338-1-3:2002?

The standard requires the dielectric rod resonator method to be used for microwave measurements of complex relative permittivity. It also sets the practical range for use at 2 GHz to 20 GHz, for relative permittivity between 5 and 500, and for loss factor tan δ between 10^-5 and 10^-2. In practice, that tells the user whether the material and test frequency are suitable for this method.

Measured quantities and calculation basis

Clause 2 defines the measured parameters as ε′, tan δ, and TCF, and it relates them to resonance frequency, quality factor, temperature, and specimen expansion. Clause 3 then gives the theory and calculation equations. In practice, the measurement is not just a reading from an instrument - the final values come from resonance data, geometry, and correction terms.

Relative permittivity and loss factor

Clause 3.1 shows how ε′ and tan δ are calculated from the TE mode resonance frequency and the unloaded Q of the resonator. The method also corrects tan δ for the conductivity of the conducting plates. In practice, this means you must know the plate condition before you can trust the loss value of the specimen.

Conductivity of the conducting plates

Clause 3.2 requires the relative conductivity of the conducting plates to be determined in advance, using two standard dielectric rod resonators cut from the same cylinder but with different heights. The higher and shorter rods are measured at the same resonance frequency, and the Q difference is used to calculate plate conductivity. In practice, the standard turns the plate surface into a measured correction factor, which is important for low-loss materials.

Temperature coefficient and temperature dependence

Clause 3.3 defines TCF as a material constant and explains how resonance frequency changes with temperature and thermal expansion. It also gives a quadratic form when the frequency change is not linear with temperature. Clause 3.4 adds that tan δ at different temperatures must be corrected for the temperature dependence of plate conductivity. In practice, a lab needs temperature-controlled measurements if it wants reliable data for component design.

Specimen preparation and geometry

Clause 4.1 describes the preparation of standard dielectric rods, including polished ends that are parallel to each other and perpendicular to the axis. Clause 4.2 explains how to choose the test specimen dimensions from the mode chart so the TE mode falls in the desired range and avoids coupling with TM or HE modes. In practice, specimen geometry has a direct effect on measurement stability and unloaded Q.

Equipment and measurement conditions

Clause 5 specifies the measurement equipment and apparatus, including parallel conducting plates, semi-rigid cables, a microwave source, detector, and network analyzer. The setup also calls for the plate diameter to be about three times the specimen diameter, and the insertion attenuation to be between 20 dB and 40 dB, typically around 30 dB. In practice, the setup must suppress field disturbance while keeping the signal measurable.

Procedure and error control

Clause 6 gives the measurement sequence for complex permittivity and temperature coefficient, including reference-level measurement, repeated readings, and humidity control. Clause 7 explains the main error sources - finite plate size, conductivity uncertainty, air gaps, and field disturbance - and gives the round robin test result. In practice, the document tells users where measurement uncertainty comes from and what to control before reporting results.

What terms does SIST EN 61338-1-3:2002 define?

• Complex relative permittivity: The document writes this as ε = ε′ - jε″, where ε′ is the real part used for the main dielectric property and ε″ is the loss-related imaginary part.
• tan δ: The loss factor, defined as ε″/ε′, so lower values indicate lower microwave loss.
• TCF: The temperature coefficient of resonance frequency, a material constant that relates resonance-frequency change to temperature after allowing for thermal expansion.
• TE mode: The transverse electric resonance mode used for the permittivity and loss measurements in this standard.
• Q_u: The unloaded quality factor, which is combined with resonance frequency to derive tan δ.
• IA: Insertion attenuation, the coupling setting adjusted during measurement so the resonator response is usable without excessive disturbance.
• σ_r: Relative conductivity of the conducting plates, measured against standard annealed copper and used as a correction in the loss calculation.

Who uses SIST EN 61338-1-3:2002?

SIST EN 61338-1-3:2002 is used by material suppliers developing dielectric resonator materials and by customers designing microwave resonators and filters. It is also used in measurement laboratories, quality control teams, and engineering groups that need comparable microwave data for candidate materials. In practice, it supports material development, incoming inspection, process comparison, and laboratory reporting.

Which standards are used with SIST EN 61338-1-3:2002?

The foreword places this document within IEC 61338, and the following companion parts are named:

• IEC 61338-1-1 - General information
• IEC 61338-1-2 - Test conditions
• IEC 61338-2 - Guide to the use of waveguide type dielectric resonators
• IEC 61338-3 - Standard outlines

These parts give the wider context for the series, while Part 1-3 focuses on the microwave permittivity measurement method.

What does the SIST EN 61338-1-3:2002 document contain?

The document contains the measurement theory, equations, specimen preparation rules, test setup descriptions, procedures, and error estimates needed to use the dielectric rod resonator method. Figures 1 to 11 show the resonator configuration, mode charts, equipment layouts, resonance responses, and error behavior, while Tables 1 to 3 give example dimensions and recommended plate materials. It also includes the formulas for ε′, tan δ, plate conductivity, TCF, and temperature-dependent correction. Annex A gives the bibliography for further reading on dielectric resonator measurement methods.

SLOVENSKI STANDARD
01-september-2002
Waveguide type dielectric resonators - Part 1-3: General information and test
conditions (IEC 61338-1-3:1999)
Waveguide type dielectric resonators -- Part 1-3: General information and test conditions
- Measurement method of complex relative permittivity for dielectric resonator materials
at microwave frequency
Dielektrische Resonatoren vom Wellenleitertyp -- Teil 1-3: Allgemeine Informationen und
Prüfbedingungen - Meßverfahren für die relative Dielektrizitätskonstante von
dielektrischen Resonatorwerkstoffen im Mikrowellen-Frequenzbereich
Résonateurs diélectriques à modes guidés -- Partie 1-3: Informations générales et
conditions d'essais - Méthode de mesure de la permittivité relative complexe des
matériaux diélectriques pour les résonateurs diélectriques fonctionnant aux
hyperfréquences
Ta slovenski standard je istoveten z: EN 61338-1-3:2000
ICS:
31.140 3LH]RHOHNWULþQHLQ Piezoelectric and dielectric
GLHOHNWULþQHQDSUDYH devices
33.120.10 Koaksialni kabli. Valovodi Coaxial cables. Waveguides
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE IEC
61338-1-3
INTERNATIONAL
Première édition
STANDARD
First edition
1999-11
Résonateurs diélectriques à modes guidés –
Partie 1-3:
Informations générales et conditions d'essais –
Méthode de mesure de la permittivité relative
complexe des matériaux diélectriques pour les
résonateurs diélectriques fonctionnant aux
hyperfréquences
Waveguide type dielectric resonators –
Part 1-3:
General information and test conditions –
Measurement method of complex relative
permittivity for dielectric resonator materials at
microwave frequency
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61338-1-3 © IEC:1999 – 3 –
CONTENTS
Page
FOREWORD . 7
INTRODUCTION . 11
Clause
1 Scope and object . 13
2 Measuring parameters . 13
3 Theory and calculation equations. 15
3.1 Relative permittivity and loss factor. 15
3.2 Determination of the relative conductivity of conducting plates. 21
3.3 Temperature coefficient of resonance frequency. 23
3.4 Temperature dependence of tan δ. 27
4 Preparation of dielectric specimen . 27
4.1 Preparation of standard dielectric rods. 27
4.2 Preparation of test specimen . 29
5 Measurement equipment and apparatus. 29
5.1 Measurement equipment. 29
5.2 Measurement apparatus for complex permittivity. 31
5.3 Measurement apparatus for temperature coefficient. 35
6 Measurement procedure . 35
6.1 Measurement procedure for complex permittivity . 35
6.2 Measurement procedure for temperature coefficient. 41
7 Accuracy and error estimation. 41
7.1 Measurement error due to the size of conducting plates. 41
7.2 Measurement error of relative conductivity. 43
7.3 Errors due to the airgap between dielectric rod and conducting plates or
to field disturbance . 45
7.4 Result of round robin test (RRT) . 45
Annex A – Bibliography . 47
Figures
Figure 1 – Configuration of a cylindrical dielectric rod resonator short-circuited at both
ends by two parallel conducting plates . 15
Figure 2 – Chart for relative permittivity calculation using TE mode. 17
"01
Figure 3 – Confirmation of standard dielectric rod resonators for measurement
of conductivity of conducting plates . 21
Figure 4 – Temperature dependence of f (figure 4a) and tan δ (figure 4b) for
five kinds of dielectrics (ε' = 21, 25, 30, 38 and 90) . 25
Figure 5 – Mode chart of a dielectric rod resonator short-circuited at both ends
by parallel conducting plates . 31
Figure 6 – Schematic diagram of measurement equipment. 33
Figure 7 – Measurement apparatus for complex permittivity . 33

61338-1-3 © IEC:1999 – 5 –
Figure 8 – Measurement apparatus for temperature coefficient . 35
Figure 9 – Frequency response for TE mode resonator having ε' = 37,5, d = 8,00 mm
and h = 3,3 mm . 39
Figure 10 – Insertion attenuation IA , resonance frequency f and
0 0
half-power bandwidth Δf . 39
Figure 11 – Measurement error on ε' and tan δ by the size ratio d'/d. 43
Tables
Table 1 – Examples of dimensions for standard dielectric rods. 27
Table 2 – Example of TE mode resonance frequency for various ε′ and
dimensions of a dielectric specimen . 29
Table 3 – Recommended dimensions and materials for conducting plate . 35

61338-1-3 © IEC:1999 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
––––––––––––
WAVEGUIDE TYPE DIELECTRIC RESONATORS –
Part 1-3: General information and test conditions –
Measurement method of complex relative permittivity for
dielectric resonator materials at microwave frequency
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61338-1-3 has been prepared by IEC technical committee 49:
Piezoelectric and dielectric devices for frequency control and selection.
The text of this standard is based on the following documents:
FDIS Report on voting
49/444/FDIS 49/449/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annex A is for information only.
This standard forms part 1-3 of IEC 61338.

61338-1-3 © IEC:1999 – 9 –
IEC 61338, Waveguide type dielectric resonators, consists of the following parts:
Part 1-1: General information and test conditions – General information (IEC 61338-1-1)
Part 1-2: General information and test conditions – Test conditions (IEC 61338-1-2)
Part 1-3: General information and test conditions – Measurement method of complex relative
permittivity for dielectric resonator materials at microwave frequency (IEC 61338-1-3)
Part 2: Guide to the use of waveguide type dielectric resonators (IEC 61338-2) (under
consideration)
Part 3: Standard outlines (IEC 61338-3) (under consideration)
The committee has decided that this publication remains valid until 2003. At this date, in
accordance with the committee's decision, the publication will be
• reconfirmed;
 withdrawn;
 replaced by a revised edition, or
 amended.
61338-1-3 © IEC:1999 – 11 –
INTRODUCTION
Dielectric materials for microwave resonators and filters have high relative permittivity, a low
loss factor and superior temperature stability of resonance frequencies. Knowledge of these
parameters is of primary importance for the development of new materials on the supplier side
and for the design of dielectric microwave components on the customer side.
The parameters of dielectric resonator materials needed for the design of microwave
components are:
– the real component ε' of the complex relative permittivity;
– the loss factor tan δ;
– the temperature coefficient of resonance frequency (TCF);
– the temperature dependence of tan δ.
Several measurement methods are proposed to determine the complex permittivity at
microwave frequencies:
– the dielectric rod resonator method using TE resonance mode;
– the cylindrical cavity method using TE resonance mode;
01δ
– the perturbation method using a cylindrical cavity;
– the S-parameter method using a coaxial line.

61338-1-3 © IEC:1999 – 13 –
WAVEGUIDE TYPE DIELECTRIC RESONATORS –
Part 1-3: General information and test conditions –
Measurement method of complex relative permittivity for
dielectric resonator materials at microwave frequency
1 Scope and object
This part of IEC 61338 describes the dielectric rod resonator measurement method for a wide
range of microwave dielectric properties in practical applications. This method has the
following characteristics:
– a complete and exact mathematical solution of complex relative permittivity is given by
easy computer software;
–4
– the measurement error is less than 0,3 % for ε′ and less than 0,05 × 10 for tan δ;

– the TCF is directly measured without any compensation with a measurement error less
–6
than 1 × 10 /K.
The object of this standard is to describe the measurement methods of the complex relative
permittivity of dielectric resonator materials at microwave frequencies by means of the
dielectric rod resonator method short-circuited at both ends by parallel conducting plates. The
measuring parameters are ε′, tan δ, TCF and the temperature dependence of tan δ at the
resonance frequency. The dielectric materials are assumed to be isotropic and homogeneous.
2 Measuring parameters
The terms of the measuring parameters are defined as follows:
ε = ε' – jε'' = D/(ε E)(1)
r 0
tan δ = ε''/ε' (2)
TCF = − TC ε − α (3)
where
D is the electric flux density;
E is the electric field strength;
ε is the electric constant;
ε ε ε
' and '' are the real and imaginary components of the complex relative permittivity .
r
It should be noted that the TCF is defined by equation (3) as the material constant, TCε being
the temperature coefficient of relative permittivity and α the coefficient of thermal expansion
of the dielectric specimen. Each of the temperature coefficients is given as follows:

61338-1-3 © IEC:1999 – 15 –
f − f
T ref
–6
TCF =   × (1 × 10 /K) (4)
T − T
f
ref
ref
ε − ε
T ref
–6
TCε =   ×  (1 × 10 /K) (5)
ε T − T
ref ref
1 h − h
T ref
–6
α =  × 10 (1 × 10 /K) (6)
h T − T
ref ref
where
f and f are the resonance frequencies at temperature T and reference temperature T
T ref ref
(T = 20 °C to 25 °C);
ref
ε and ε are the real parts of the complex relative permittivity at temperatures T and T ;
T ref ref
h and h are the lengths of the dielectric specimen which is assumed to be isotropic at

T ref
temperatures T and T .
ref
The applicable measuring ranges of dielectric properties for this method are the following:
– frequency: 2 GHz < f < 20 GHz;
– relative permittivity: 5 < ε′ < 500;
–5 –2
– loss factor: 10 < tan δ < 10 .
3 Theory and calculation equations
3.1 Relative permittivity and loss factor
Figure 1 shows the configuration of the TE mode resonator. A cylindrical dielectric rod is
"0m
short-circuited at both ends by the two parallel conducting plates, thus constituting a
resonator. The values ε′ and tan δ of this resonator are calculated from the measured
resonance frequency (f ) and unloaded quality factor (Q ) of the TE mode resonance:
0 u "0m
TE , TE and TE modes are commonly used.
011 012 013
IEC  1574/99
Figure 1 – Configuration of a cylindrical dielectric rod resonator short-circuited at both ends
by two parallel conducting plates

61338-1-3 © IEC:1999 – 17 –
The relative permittivity ε′ is calculated using the measured resonance frequency, the
*
diameter d and the height h of the dielectric specimen .
The free space resonance wavelength λ and the guiding wavelength in the dielectric
transmission line λ are given by the following equations:
g
c 2 h
λ = , λ = , � = 1, 2 . . . (7)
0 g
f"0
where c is the velocity of light in a vacuum (c = 2,9979 × 10 m/s).
The value ν is calculated next from λ and λ :
0 g
 
 
 
πd λ
2 0
 
 
ν =   − 1 (8)
 
 
 
λ λ
 0  g
 
 
 
2 2
Using the value ν , the value u is given by the following transcendental equation:
J (u) K (ν )
0 0
u = −ν (9)
J (u) K (ν )
l l
where J (u) is the Bessel function of the first kind and K (v) is the modified Bessel function
n n
of the second kind. For any value of v, the mth solution u exists between u and u ,
0m 1m
where J (u ) = 0 and J (u ) = 0. The first solution (m = 1) is shown in figure 2 by curve A.
0 0m 1 1m
IEC  1575/99
Figure 2 – Chart for relative permittivity calculation using TE mode
"01
––––––––-
*
In the following text of this standard, the height is identical with the length, because the bar to be measured is
placed vertically in the measuring fixture.

61338-1-3 © IEC:1999 – 19 –
2 2
The relative permittivity is calculated from v and u :
 
λ
2 2
 
ε ′ = ()+ +1 (10)
u v
 
πd
 
In the following, tan δ is given from the measured unloaded Q:
A A B′
tan δ =  − =  − (11)
BR
s
Q Q
σ
u u r
where
π f μ π f μ f
−2
0 0 0
R = = = 0,825 × 10 (12)
s
σ σ σ σ
0 r r
R being expressed in ohms (Ω) and f in gigahertz (GHz)
s 0
 
σ
=   (13)
σ
r
 
σ
 
W
A = 1 + (14)
ε ′
 
λ 1 + W π f μ
0 0
 
B = , B′ = B (15)
 
λ σ
30 π ε ′" 0
g
 
2 2
J (u) K (v) k (v) − K (v)
l 0 2 l
W = (16)
2 2
K (v) J (u) − J (u) J (u)
l l 0 2
In equation (12), R and σ are the surface resistance and the conductivity of conducting
s
plates, respectively. The relative conductivity σ , defined in equation (13), is the ratio of
r
the measured conductivity to the conductivity of the international standard annealed copper
σ (σ = 5,8 × 10 S/m at 20 °C). σ is used instead of R because σ is independent of
0 0 r s r
frequency.
–2 7
The constant (0,825 × 10 ) in equation (12) is calculated from the value σ = 5,8 × 10 S/m
–7
and the magnetic constant μ = 4 π × 10 H/m since μ equals μ in a non-magnetic dielectric
0 0
specimen.
The function W/ε′ equals the ratio of the electric-field energy stored outside to that inside the
dielectric rod. If all of the electric field energy is concentrated inside the dielectric rod, the
value W equals zero. The computed result of the W – v relation for m = 1 of the TE mode
"0m
resonance is shown in figure 2 by curve B.

61338-1-3 © IEC:1999 – 21 –
3.2 Determination of the relative conductivity of conducting plates
As equation (11) shows, the effective value of R or σ of the conducting plates, which are
s r
commonly made of silver or copper, shall be determined in advance of the calculation of tan δ.
The accuracy of measured σ has vital importance in the determination of tan δ because the
r
terms (A/Q ) and (B'/ σ ) have the same order of magnitude for a low-loss dielectric
u r
–4
specimen with tan δ in the order of 10 .
The effective value of σ of the conducting plates shall be measured not at direct current but
r
at microwave frequencies due to the skin effect on conductivity. In order to measure σ , two
r
dielectric rod samples which are called standard dielectric rod resonators are used. As
figure 3 shows, these two rods have the same diameter but different heights. The rod heights
are such that one rod is " times the height of the other; " is commonly set equal to three.
The rod heights are cut from one cylindrical dielectric rod and have the same values of ε′ and
tan δ.
Figure 3 shows the configuration of the standard dielectric rod resonators in the case of " = 3.
The resonance frequency and unloaded Q of the TE mode are measured using the shorter
rod, and those of the TE mode are measured using the higher rod. We denote the f and
0 "01
Q for each resonator by using the subscripts 1 and ", respectively: f and Q for the
u 01 u1
shorter rod, and f and Q for the higher rod.
0""u
When the higher rod is precisely " times higher than the shorter rod, f coincides with f .
0"
But Q is higher than Q according to the different magnitude of conductor loss on the
u1 "u
conducting plates.
IEC  1576/99 IEC  1577/99
Figure 3a – TE mode resonance Figure 3b – TE mode resonance
011 013
Figure 3 – Configuratio
...