IEC TS 61994-1:2007

IEC/TS 61994-1
Edition 2.0 2007-08
TECHNICAL
SPECIFICATION
Piezoelectric and dielectric devices for frequency control and selection –
Glossary –
Part 1: Piezoelectric and dielectric resonators

IEC/TS 61994-1:2007(E)
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IEC/TS 61994-1
Edition 2.0 2007-08
TECHNICAL
SPECIFICATION
Piezoelectric and dielectric devices for frequency control and selection –
Glossary –
Part 1: Piezoelectric and dielectric resonators

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 31.140; 01.040.31 ISBN 2-8318-9298-8

– 2 – TS 61994-1 © IEC:2007(E)
CONTENTS
FOREWORD.3

1 Scope.5
2 Normative references .5
3 Terms and definitions .5

Figure 1 – Configuration of a dielectric resonator (TE mode type) .8

01δ
Figure 2 – Equivalent circuit of a piezoelectric vibrator (one-port resonator) .9
Figure 3 – Frequency characteristics of the impedance near resonance.11
Figure 4 – Equivalent circuit for a two-port SAW resonator .12
Figure 5 – Configuration of an interdigital transducer (IDT) .13
Figure 6 – Configuration of a one port SAW resonator .16
Figure 7 – Configuration of a two port SAW resonator.21

TS 61994-1 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
PIEZOELECTRIC AND DIELECTRIC DEVICES
FOR FREQUENCY CONTROL AND SELECTION –
GLOSSARY –
Part 1: Piezoelectric and dielectric resonators

FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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The main task of IEC technical committees is to prepare International Standards. In exceptional
circumstances, a technical committee may propose the publication of a technical specification
when
– the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
– the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
IEC 61994-1, which is a technical specification, has been prepared by IEC technical committee
49: Piezoelectric and dielectric devices for frequency control and selection.
This second edition of IEC 61994-1 cancels and replaces the first edition published in 2003.
This edition constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– definitions updated;
– terminology given in orderly sequence;

– 4 – TS 61994-1 © IEC:2007(E)
– drawings inserted for easier understanding.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
49/761/DTS 49/766/RVC
Full information on the voting for the approval of this technical specification can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the IS0/lEC Directives, Part 2.
IEC 61994 consists of the following parts under the general title: Piezoelectric and dielectric
devices for frequency control and selection – Glossary:
－ Part 1: Piezoelectric and dielectric resonators
－ Part 2: Piezoelectric and dielectric filters
－ Part 3: Piezoelectric oscillators
－ Part 4-1: Piezoelectric materials – Synthetic quartz crystal
－ Part 4-2: Piezoelectric and dielectric materials – Piezoelectric ceramics
－ Part 4-3: Materials for dielectric devices
－ Part 4-4: Materials – Materials for Surface Acoustic Wave (SAW) devices
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an international standard;
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

___________
To be published.
TS 61994-1 © IEC:2007(E) – 5 –
PIEZOELECTRIC AND DIELECTRIC DEVICES
FOR FREQUENCY CONTROL AND SELECTION –
GLOSSARY –
Part 1: Piezoelectric and dielectric resonators

1 Scope
This technical specification gives the terms and definitions for piezoelectric and dielectric
resonators representing the present state-of-the-art, which are intended for use in the standards
and documents of IEC technical committee 49.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of the
referenced document (including any amendments) applies.
IEC 60050(561):1991, International Electrotechnical Vocabulary (IEV) – Chapter 561:
Piezoelectric devices for frequency control and selection
Amendment 1 (1995)
IEC 60122-1:2002, Quarts crystal units of assessed quality – Part-1: Generic specification
IEC 60642:1979, Piezoelectric ceramic resonators and resonator units for frequency control and
selection – Chapter I: Standard values and conditions – Chapter II: Measuring and test
conditions
IEC 61019-1:2004, Surface acoustic wave (SAW) resonators – Part 1: Generic specification
IEC 61338-1:2004, Waveguide type dielectric resonators – Part 1: Generic specification
3 Terms and definitions
3.1
adjustment tolerance
the maximum permissible deviation of the working frequency of a piezoelectric resonator from
the nominal frequency at the reference temperature under specified conditions
[IEV 561-02-16 modified]
3.2
ageing tolerance
the maximum permissible deviation of the working frequency of a piezoelectric resonator from its
initial frequency which is observed with the passage of time under specified conditions
[IEV 561-02-17 modified]
3.3
ageing – long-term parameter variation
relationship which exists between any parameter (for example resonance frequency) and time
[IEC 61019-1, 4.2.9]
3.4
apodisation (spurious suppression for SAW devices)
weighting method produced by the change in finger overlap over the length of the IDT to
suppress the transverse spurious modes

– 6 – TS 61994-1 © IEC:2007(E)
[IEV 561-06-18 modified]
3.5
anti-resonance frequency
f
a
the higher of two frequencies of a piezoelectric resonator vibrating alone, under specified
conditions, at which the electrical impedance of the resonator is resistive
[IEV 561-02-10]
3.6
bus bar
common electrode region of an IDT which connects individual fingers together and also
connects the IDT to an external circuit (see Figure 5)
[IEV 561-06-15 modified]
3.7
capacitance ratio
C
r =
C
where C and C represent the shunt capacitance and the motional capacitance respectively
0 1
in the equivalent circuit (see Figure 2)
the capacitance ratio indicates one of the merits of the resonator
[IEC 61019-1, 4.2.10.9 modified]
3.8
centre frequency of a two-port SAW resonator
f
c
arithmetic mean of two frequencies at which the attenuation relative to the minimum insertion
attenuation reaches a specified value
[IEC 61019-1, 4.2.11.9]
3.9
clamped capacitance (of a piezoelectric resonator)
the capacitance of a piezoelectric resonator measured at a frequency well above any
pronounced resonance
NOTE In practice, the value of the capacitance is often indirectly determined, because a direct measurement is
affected by the presence of factors such as lead inductance.
[IEV 561-02-35]
3.10
coaxial dielectric resonator
dielectric resonator characterized by a TEM mode field distribution with a coaxial waveguide
structure of finite length
[IEC 61338-1, 2.2.19]
TS 61994-1 © IEC:2007(E) – 7 –
3.11
coplanar resonator
dielectric resonator characterised by a TEM mode field distribution. The structure is a
coplanar-line waveguide of finite length
[IEC 61338-1, 2.2.4]
3.12
coupling coefficient of SAW materials
k
s
the SAW electromechanical coupling coefficient is defined as follows:
Δv
k = 2
S
v
where Δv/v is the relative velocity change produced by short-circuiting the surface potential from
the open-circuit condition
[IEC 60862-2, 3.1.8; IEC 61019-1, 4.1.12]
3.13
crystal element
piezoelectric substrate cut to a given geometric shape, size and orientation with respect to the
crystallographic axes of the crystal
[IEC 60122-1, 2.2.1]
3.14
crystal resonator
the mounted crystal element that vibrates when an alternating electric field is applied between
the electrodes
[IEC 60122-1, 2.2.3 modified]
3.15
crystal unit
a crystal resonator mounted in an enclosure
[IEC 60122-1, 2.2.7]
...