SIST EN 62047-7:2011

Semiconductor devices - Micro-electromechanical devices - Part 7: MEMS BAW filter & duplexer for radio frequency control and selection

This part of IEC 62047 describes terms, definition, symbols, configurations, and test methods that can be used to evaluate and determine the performance characteristics of BAW resonator, filter, and duplexer devices as radio frequency control and selection devices. This standard specifies the methods of tests and general requirements for BAW resonator, filter, and duplexer devices of assessed quality using either capability or qualification approval procedures.

Halbleiterbauelemente - Bauelemente der Mikrosystemtechnik - Teil 7: BAW-MEMS-Filter und -Duplexer zur Hochfrequenz-Regelung und -Auswahl

Dispositifs à semiconducteurs - Dispositifs microélectromécaniques - Partie 7: Filtre & duplexeur BAW MEMS pour la commande et le choix des fréquences radioélectriques

La CEI 62047-7:2011 définit les termes, les définitions, les symboles, les configurations, et les méthodes d'essai susceptibles d'être utilisés pour évaluer et déterminer les caractéristiques d'aptitude à la fonction des dispositifs de résonateurs, filtres et duplexeurs BAW en tant que dispositifs de commande et de choix des fréquences radioélectriques. La présente norme spécifie les méthodes d'essai et les exigences générales relatives aux dispositifs de résonateur, de filtre et de duplexeur BAW sous assurance de la qualité, au moyen des procédures d'agrément de savoir-faire ou d'homologation.

Polprevodniški elementi - Mikroelektromehanski elementi - 7. del: Filter & duplekser MEMS BAW za radiofrekvenčno krmiljenje in izbiranje

Ta del IEC 62047 opisuje izraze, definicijo, simbole, konfiguracije in preskusne metode, ki se lahko uporabljajo za vrednotenje in določevanje značilnosti delovanja resonatorja, filtra in duplekserja BAW kot naprav za radiofrekvenčno krmiljenje in izbiranje. Ta standard določa preskusne metode in splošne zahteve za resonatorje, filtre in duplekserje BAW ocenjene kakovosti z uporabo postopkov za odobritev zmogljivosti ali usposobljenosti.

General Information

• Status: Published
• Publication Date: 14-Sep-2011
• ICS: 31.080.01 - Semiconductor devices in general
• Technical Committee: I11 - Imaginarni 11
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-Sep-2011
• Due Date: 12-Nov-2011
• Completion Date: 15-Sep-2011
• Ref Project: EN 62047-7:2011 - Semiconductor devices - Micro-electromechanical devices - Part 7: MEMS BAW filter and duplexer for radio frequency control and selection

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 62047-7:2011
01-oktober-2011
3ROSUHYRGQLãNLHOHPHQWL0LNURHOHNWURPHKDQVNLHOHPHQWLGHO)LOWHU
GXSOHNVHU0(06%$:]DUDGLRIUHNYHQþQRNUPLOMHQMHLQL]ELUDQMH
Semiconductor devices - Micro-electromechanical devices - Part 7: MEMS BAW filter &
duplexer for radio frequency control and selection
Dispositifs à semiconducteurs - Dispositifs microélectromécaniques - Partie 7: Filtre &
duplexeur BAW MEMS pour la commande et le choix des fréquences radioélectriques
Ta slovenski standard je istoveten z: EN 62047-7:2011
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
SIST EN 62047-7:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 62047-7:2011

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SIST EN 62047-7:2011

EUROPEAN STANDARD
EN 62047-7

NORME EUROPÉENNE
August 2011
EUROPÄISCHE NORM

ICS 31.080.99


English version


Semiconductor devices -
Micro-electromechanical devices -
Part 7: MEMS BAW filter and duplexer for radio frequency control and
selection
(IEC 62047-7:2011)


Dispositifs à semiconducteurs -  Halbleiterbauelemente -
Dispositifs microélectromécaniques - Bauelemente der Mikrosystemtechnik -
Partie 7: Filtre et duplexeur BAW MEMS Teil 7: BAW-MEMS-Filter und -Duplexer
pour la commande et le choix des zur Hochfrequenz-Regelung und -Auswahl
fréquences radioélectriques (IEC 62047-7:2011)
(CEI 62047-7:2011)





This European Standard was approved by CENELEC on 2011-07-21. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62047-7:2011 E

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SIST EN 62047-7:2011
EN 62047-7:2011 - 2 -
Foreword
The text of document 47F/79/FDIS, future edition 1 of IEC 62047-7, prepared by SC 47F, Micro-
electromechanical systems, of IEC TC 47, Semiconductor devices, was submitted to the IEC-CENELEC
parallel vote and was approved by CENELEC as EN 62047-7 on 2011-07-21.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2012-04-21
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2014-07-21
with the EN have to be withdrawn
__________
Endorsement notice
The text of the International Standard IEC 62047-7:2011 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60368-1:2000 NOTE  Harmonized as EN 60368-1:2000 + A1:2004 (not modified).
+ A1:2004
IEC 60368-2-2 NOTE  Harmonized as EN 60368-2-2.
IEC 60862-1:2003 NOTE  Harmonized as EN 60862-1:2003 (not modified).
IEC 60862-2 NOTE  Harmonized as EN 60862-2.
__________

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SIST EN 62047-7:2011

IEC 62047-7
®

Edition 1.0 2011-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside


Semiconductor devices – Micro-electromechanical devices –
Part 7: MEMS BAW filter and duplexer for radio frequency control and selection

Dispositifs à semiconducteurs – Dispositifs microélectromécaniques –
Partie 7: Filtre et duplexeur BAW MEMS pour la commande et le choix des
fréquences radioélectriques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 31.080.99 ISBN 978-2-88912-537-1

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 62047-7:2011
– 2 – 62047-7  IEC:2011
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
3.1 General terms . 6
3.2 Related with BAW filter . 7
3.3 Related with BAW duplexer . 9
3.4 Characteristic parameters . 10
3.4.1 BAW resonator . 10
3.4.2 BAW filter and duplexer . 13
3.4.3 Temperature characteristics . 16
4 Essential ratings and characteristic parameters . 16
4.1 Resonator, filter and duplexer marking . 16
4.2 Additional information . 17
5 Test methods . 17
5.1 Test procedure . 17
5.2 RF characteristics . 19
5.2.1 Insertion attenuation, IA . 19
5.2.2 Return attenuation, RA . 20
5.2.3 Bandwidth . 21
5.2.4 Isolation . 21
5.2.5 Ripple . 22
5.2.6 Voltage standing wave ratio (VSWR) . 22
5.2.7 Impedances of input and output . 23
5.3 Reliability test method . 23
5.3.1 Test procedure . 23
Annex A (informative) Geometries of BAW resonators . 25
Annex B (informative) Operation of BAW resonators . 26
Bibliography . 28

Figure 1 – Basic structure of BAW resonator . 7
Figure 2 – Topologies for BAW filter design . 8
Figure 3 – Frequency responses of ladder and lattice type BAW filters . 8
Figure 4 – An example of BAW duplexer configuration . 9
Figure 5 – Equivalent circuit of BAW resonator (one-port resonator) . 10
Figure 6 – Measurement procedure of BAW filters and duplexers . 18
Figure 7 – Electrical measurement setup of BAW resonators, filters and duplexers . 19
Figure 8 – Insertion attenuation of BAW filter . 20
Figure 9 – Return attenuation of BAW filter . 21
Figure 10 – Isolation (Tx-Rx) of BAW duplexer . 22
Figure 11 – Ripple of BAW filter . 22
Figure 12 – Smith chart plot of input and output impedances of BAW filter . 23
Figure 13 – Block diagram of a test setup for evaluating the reliability of BAW
resonators and filters . 24

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SIST EN 62047-7:2011
62047-7  IEC:2011 – 3 –
Figure A.1 – Geometry comparison of BAW resonators . 25
Figure B.1 – Modified BVD (Butterworth-Van Dyke) equivalent circuit model . 27

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SIST EN 62047-7:2011
– 4 – 62047-7  IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 7: MEMS BAW filter and duplexer
for radio frequency control and selection


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of 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, IEC publishes International Standards, Technical Specifications,
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agreement between the two organizations.
2) The formal decisions or agreements of 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62047-7 has been prepared by subcommittee 47F: Micro-
electromechanical systems, of IEC technical committee 47: Semiconductor devices.
The text of this standard is based on the following documents:
FDIS Report on voting
47F/79/FDIS 47F/87/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 2.

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SIST EN 62047-7:2011
62047-7  IEC:2011 – 5 –
The committee has decided that the contents of this publication will remain unchanged until
the stability 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
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

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SIST EN 62047-7:2011
– 6 – 62047-7  IEC:2011
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 7: MEMS BAW filter and duplexer
for radio frequency control and selection



1 Scope
This part of IEC 62047 describes terms, definition, symbols, configurations, and test methods
that can be used to evaluate and determine the performance characteristics of BAW resonator,
filter, and duplexer devices as radio frequency control and selection devices. This standard
specifies the methods of tests and general requirements for BAW resonator, filter, and
duplexer devices of assessed quality using either capability or qualification approval
procedures.
2 Normative references
Void.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General terms
3.1.1
bulk acoustic wave
BAW
acoustic wave propagating in a bulk body
3.1.2
BAW resonator
resonator employing bulk acoustic wave
NOTE BAW resonator consists of piezoelectric material between top and bottom electrodes, as shown in Figure 1.
The top and bottom electrodes which can be made to vibrate in a vertical direction of the deposited piezoelectric
film. The electrodes are either two air-to-solid interfaces or an acoustic Bragg reflector and an air-to-solid interface.
The former is often called the film bulk acoustic resonator (FBAR), and the latter is called the solidly-mounted
resonator (SMR).

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SIST EN 62047-7:2011
62047-7  IEC:2011 – 7 –
Air-to-solid
Electrode Piezoelectric film
interface
AC power
supply
IEC  1211/11

Key
Layers of a piece of BAW resonator   Components to operate a BAW resonator
Electrode To provide electrical input to a body of AC power Electric power supply to vibrate a
piezoelectric film and electrical connections supply BAW resonator
with a external circuit
Piezoelectric Body layer of a kind of BAW resonator
film
Air to solid
interface
Figure 1 – Basic structure of BAW resonator
3.1.3
electrode
electrically conductive plate in proximity to or film in contact with a face of the piezoelectric
film by means of which a polarizing or driving field is applied to the element
[IEC/TS 61994-1, 3.21]
3.1.4
piezoelectric film
film which has piezoelectricity
NOTE Piezoelectric films can be distinguished as non-ferroelectric and ferroelectric materials. The non-
ferroelectric materials, such as AlN (aluminium nitride) and ZnO (zinc oxide) have low dielectric constant, small
dielectric loss, good hardness, and excellent insulating properties. Thus, they are good for microwave resonator
and filter applications. The ferroelectric materials, such as PZT (lead-zirconate-titanate) and PLZT (lead-
lanthanum-zirconate) have high dielectric constant, large dielectric loss, and fair insulating properties. Thus, they
are good for memory and actuator applications.
3.1.5
direct piezoelectric effect
effect which a mechanical deformation of piezoelectric material produces a proportional
change in the electric polarization of that material
3.1.6
converse (or reverse) piezoelectric effect
effect which mechanical stress proportional to an acting external electric field is induced in
the piezoelectric material
NOTE Converse piezoelectric effect is widely being used for acoustic wave resonators and filters, resonant
sensors, oscillators, ultrasonic wave generators, and actuators. Direct piezoelectric effect is usually applied for
various piezoelectric sensors and voltage generators.
3.2 Related with BAW filter
Figure 2 shows topologies for BAW filter design.

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SIST EN 62047-7:2011
– 8 – 62047-7  IEC:2011

IEC  1212/11 IEC  1213/11
a) Ladder type b) Lattice type
Figure 2 – Topologies for BAW filter design
NOTE BAW resonators are connected in series and parallel for forming electrical filters, as shown in Figure 2.
The resonant frequencies of series and parallel resonators should be different to secure the bandwidth of the BAW
filter.
3.2.1
ladder filter
filter having a cascade or tandem connection of alternating series and shunt BAW resonators
NOTE BAW resonator connected in series should have slightly higher resonant frequency than that of a parallel
BAW resonator. The parallel resonant frequency of the parallel BAW resonator needs to be equal to the series
resonant frequency of the series BAW resonator in the filter geometry shown in Figure 2. It gives a steep roll-off,
but poor stop-band rejection characteristics as shown in Figure 3a). Thus, helper inductors are usually given to
improve the isolation, and in general, the out-of-band rejection far from the passband becomes worse.

Frequency Frequency

IEC  1214/11 IEC  1215/11

a) Ladder type   b) Lattice type
Figure 3 – Frequency responses of ladder and lattice type BAW filters
3.2.2
lattice filter
filter having two pairs of resonators electrically coupled in a bridge network, with one pair of
resonators in a series arm and the other pair in a shunt arm
[IEC 60862-1: 2003, 2.2.3.8 modified]
NOTE Lattice type filter need more resonators than ladder type one, sine it needs two resonators to synthesize
one pole and one transmission zero from the transfer function. The pass-band is obtained when one pair of
resonators behaves inductive while the other pair of resonators behaves capacitive. Unlike the ladder type filter, it
gives a deep stop-band rejection and good power handling capability, but smooth roll-off characteristics as shown
in Figure 3 b).
Insertion attenuation  (dB)
Insertion attenuation  (dB)

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SIST EN 62047-7:2011
62047-7  IEC:2011 – 9 –
3.2.3
helper inductor
inductor connected with shunt resonators of ladder BAW filter
3.3 Related with BAW duplexer
Figure 4 shows an example of BAW duplexer configuration.
Tx
BAW filter
Ant
Rx
TL
phase

IEC  1216/11
Key
Tx transmitting port  Rx receiving port
Ant antenna port  TL phase delay line
phase
Figure 4 – An example of BAW duplexer configuration
NOTE Two different BAW filters, transmitting and receiving band pass filters, are connected with a quarter
wavelength phase shifter, phase delay line, or parallel inductor on a package substrate for forming a duplexer, as
shown in Figure 4. In order to improve isolation characteristics between these transmitting and receiving filters, via
grounds should be well formed onto the package substrate. Series and shunt inductors are added into the Tx and
Rx filters in order to improve its attenuation, roll-off, and ripple characteristics.
3.3.1
transmitting band pass filter
Tx
band pass filter used at the transmitter of the RF system which transmits a signal to the
antenna
3.3.2
receiving band pass filter
Rx
band pass filter used at the receiver of the RF system which receives a signal from the
antenna
3.3.3
phase delay line
transmission line to delay a signal from a port to the antenna or isolate the transmitter and
receiver

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SIST EN 62047-7:2011
– 10 – 62047-7  IEC:2011
3.4 Characteristic parameters
3.4.1 BAW resonator
3.4.1.1
equivalent circuit (of BAW resonators)
electrical circuit which has the same impedance as a piezoelectric resonator in the immediate
neighborhood of resonance
NOTE For example, one port BAW resonator consists of series elements L , C , R in parallel with C as shown
m m m o
in Figure 5, where L , C , R represent the motional inductance, capacitance, and resistance, respectively. C
m m m o
represents the shunt capacitance. Sometimes, another resistance R is added in series with an input terminal for
s
taking account of electrode and interconnection resistance.
C
o
R C L
m m m

IEC  1217/11
Key
C shunt capacitance  R motional resistance
0 m
C motional capacitance L motional inductance
m m
Figure 5 – Equivalent circuit of BAW resonator (one-port resonator)
[IEC/TS 61994-1: 2007, 3.25 modified]
3.4.1.2
nominal frequency
frequency assigned by the specification of the resonator
[IEC/TS 61994-1: 2007, 3.58 modified]
3.4.1.3
resonant frequency (or series resonant frequency)
f
r
lower frequency of the two frequencies of a piezoelectric resonator vibrating alone under
specified conditions, at which the electrical impedance of the resonator is resistive
[IEC/TS 61994-1: 2007, 3.81 modified]
3.4.1.4
anti-resonant frequency (parallel resonant frequency, f )
p
f
a
the higher frequency of two frequencies of a piezoelectric resonator vibrating alone. An
approximate value of this frequency is given by the expression
f =1/ 2π L C C /(C + C )
 (1)
p m m 0 m 0
where
C represents the shunt capacitance; and
0

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SIST EN 62047-7:2011
62047-7  IEC:2011 – 11 –
L and C are the motional inductance and capacitance
m m
[IEC/TS 61994-1: 2007, 3.3, 3.69 modified]
3.4.1.5
motional (series) resonant frequency
f
s
resonant frequency of the motional or series arm of the equivalent circuit of the resonator, it is
defined by the following formula
1
f = (2)
s
2π L C
m m
where
L
and C represent the motional inductance and capacitance respectively .
m m
[IEC/TS 61994-1: 2007, 3.55 modified]
3.4.1.6
fundamental resonance
lowest resonance mode in a given family of vibration
3.4.1.7
spurious resonance
state of resonance of a resonator other than that associated with the working frequency
[IEC/TS 61994-1: 2007, 3.86 modified]
3.4.1.8
spurious resonance rejection level
difference between the maximum level of spurious resonances and the minimum insertion
attenuation
[IEC/TS 61994-1: 2007, 3.87 modified]
3.4.1.9
unwanted response
state of resonance of a resonator other than that associated with the mode of vibration
intended for the application
[IEC/TS 61994-1: 2007, 3.99 modified]
3.4.1.10
capacitance ratio
r
to the motional capacitance C
ratio of the parallel capacitance C
0 m
[IEC/TS 61994-1: 2007, 3.7 modified]
3.4.1.11
motional capacitance
C
m
capacitance of the motional or series arm of the resonator equivalent circuit

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SIST EN 62047-7:2011
– 12 – 62047-7  IEC:2011
3.4.1.12
motional inductance
L
m
inductance of the motional or series arm of the resonator equivalent circuit
3.4.1.13
motional resistance
R
m
resistance of the motional or series arm of the resonator equivalent circuit
[IEC/TS 61994-1: 2007, 3.52 modified]
3.4.1.14
shunt capacitance
C
0
capacitance in parallel with the motional arm of the resonator equivalent circuit which is
caused by the energy leakage and dielectric loss of the piezoelectric film
3.4.1.15
figure of merit
FOM or M
2
factor indicating performance of the device, product of both k and Q, which indicates the
eff
activity of the resonator, and the value usually given by Q/r, where Q is the Q factor and r is
the ratio of capacitances at low frequencies
[IEC/TS 61994-1: 2007 modified]
3.4.1.16
electromechanical coupling factor
certain combination of elastic, dielectric and piezoelectric constants which appears naturally
in the expression of impedance of a resonator. A different factor arises in each particular
family of mode of vibration. The factor is closely related to the relative frequency spacing and
is a convenient measure of piezoelectric transduction. Alternatively, the coupling factor may
be interpreted as the square root of the ratio of the electrical or mechanical work which can
be accomplished to the total energy stored from a mechanical or electrical power source for a
particular set of boundary conditions
[IEC/TS 61994-1: 2007, 3.22 modified]
3.4.1.17
relative frequency spacing

B
s
ratio of the difference between the parallel resonance frequency f and the series resonance
p
frequency f in a given mode of vibration, to the series resonance frequency
s
B = ( f − f ) / f (3)
s p s p
[IEC TS61994-1: 2007, 3.80 modified]
3.4.1.18
effective electromechanical coupling factor
2

k
eff
the effective electromechanical coupling factor for thickness-longitudinal vibration is defined
as follows:
 
   
π f π f
2
r r
    (4)
k = / tan
 
eff
   
2 f 2 f
 a  a
 

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SIST EN 62047-7:2011
62047-7  IEC:2011 – 13 –
when the piezoelectric film is mechanically isolated from surroundings such as electrodes
3.4.1.19
electromechanical coupling factor (of piezoelectric material)
2
K
figure indicating piezoelectric strength of piezoelectric material is defined as follows:
2
K
2
k = (5)
eff
2
( )
1+ K
NOTE It depends not only materials but also the wave type and the wave propagation direction and polarization.
3.4.1.20
quality factor (for a series resonant circuit of BAW resonator)
Q
factor how long stored energy is preserved in a device and is defined as follows:
Q= 2πf L / R (6)
r m m
where
f is the resonance frequency;
r
L is the motional inductance;
m
R is the motional resistance
m
[IEC/TS61994-1: 2007, 3.77 modified]
NOTE The Q of a resonator is a measure of the losses in the device. The possible dissipative losses are
resistances in the electrodes, visco-acoustic loss in all of the materials, acoustic scattering from rough surfaces or
material defects, and acoustic radiation into the surrounding areas of the BAW device.
3.4.1.21
long-term parameter variation
relationship which exists between any parameter (for example resonance frequency) and time
3.4.2 BAW filter and duplexer
3.4.2.1
shape factor
ratio of the two bandwidths limited by two specified attenuation value
3.4.2.2
transition band
band of frequencies between a cut-off frequency and the nearest point of the adjacent stop
band
3.4.2.3
roll off rate
ratio of transition band to the ideal cut off frequency, which is an index describing the
increasing characteristics of BAW filters
3.4.2.4
attenuation
decrease in intensity of a signal, beam, or wave as a result of absorption of energy and of
scattering ou
...