1、BRITISH STANDARDBS EN 61019-2:2005Surface acoustic wave (SAW) resonators Part 2: Guide to the useThe European Standard EN 61019-2:2005 has the status of a British StandardICS 31.140g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g3
2、6g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 61019-2:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 17 October 2005 BSI 17 October 2005ISBN 0 580 46399 0National forewordThis British Standard is
3、the official English language version of EN 61019-2:2005. It is identical with IEC 61019-2:2005. It supersedes BS EN 61019-2:1997 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee EPL/49, Piezo-electric devices for frequency control and selection, which
4、has the responsibility to:A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section en
5、titled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Complianc
6、e with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related interna
7、tional and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 26, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was las
8、t issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARD EN 61019-2 NORME EUROPENNE EUROPISCHE NORM June 2005 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Ce
9、ntral Secretariat: rue de Stassart 35, B - 1050 Brussels 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61019-2:2005 E ICS 31.140 Supersedes EN 61019-2:1997English version Surface acoustic wave (SAW) resonators Part 2: Guide
10、 to the use (IEC 61019-2:2005) Rsonateurs ondes acoustiques de surface (OAS) Partie 2: Guide demploi (CEI 61019-2:2005) Oberflchenwellenresonatoren (OFW-Resonatoren) Teil 2: Leitfaden fr die Anwendung (IEC 61019-2:2005) This European Standard was approved by CENELEC on 2005-06-01. CENELEC members ar
11、e 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
12、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
13、 same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Po
14、rtugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Foreword The text of document 49/714/FDIS, future edition 2 of IEC 61019-2, prepared by IEC TC 49, Piezoelectric and dielectric devices for frequency control and selection, was submitted to the IEC-CENELEC parallel vote and w
15、as approved by CENELEC as EN 61019-2 on 2005-06-01. This European Standard supersedes EN 61019-2:1997. The main changes with respect to EN 61019-2:1997 are listed below: at the end of 5.1, the edge reflector has been added. Its reference literature has been inserted in the bibliography; in Table 1,
16、the propagation properties of LiNbO3 (64 Y) have been added; in Table 3, the clause and subclause numbers have been corrected in order to be consistent with EN 61019-1:2005. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an ident
17、ical national standard or by endorsement (dop) 2006-03-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2008-06-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61019-2:2005 was approved by CENELEC
18、 as a European Standard without any modification. _ 2 EN 61019-2:2005 3 CONTENTS INTRODUCTION.4 1 Scope.5 2 Normative references .5 3 Technical considerations 5 4 Fundamentals of SAW resonators.6 4.1 Basic structure 6 4.2 Principle of operation 6 5 SAW resonator characteristics7 5.1 Reflector charac
19、teristics7 5.2 SAW resonator characteristics.9 5.3 Spurious modes 13 5.4 Substrate materials and their characteristics .14 5.5 Available characteristics16 6 Application guide18 6.1 Oscillator circuits and oscillation condition 18 6.2 Practical remarks for oscillator applications.20 7 Checklist of SA
20、W resonator parameters for drawing up specifications 21 Bibliography24Annex ZA (normative) Normative references to international publications with their corresponding European publications .26EN 61019-2:2005 4 INTRODUCTION This part of IEC 61019 gives practical guidance to the use of SAW resonators
21、which are used in telecommunications, radio equipments and consumer products. IEC 61019-1 can be referred to for general information, standard values and test conditions. The features of these SAW resonators are small size, light weight, adjustment-free and high stability. In addition, the operating
22、 frequency of SAW resonators extends to the VHF and UHF ranges. This part has been compiled in response to a generally expressed desire on the part of both users and manufacturers for a guide to the use of SAW resonators, so that the resonators may be used to their best advantage. To this end, gener
23、al and fundamental characteristics have been explained in this guide. EN 61019-2:2005 5 SURFACE ACOUSTIC WAVE (SAW) RESONATORS Part 2: Guide to the use 1 Scope SAW resonators are now widely used in a variety of applications: VCR RF-converters, CATV local oscillators, measuring equipment, remote cont
24、rol and so on. While SAW resonators are also applied to narrow bandwidth filters, the scope of this part of IEC 61019 is limited to SAW resonators for oscillator applications It is not the aim of this guide to explain theory, nor to attempt to cover all the eventualities which may arise in practical
25、 circumstances. This guide draws attention to some of the more fundamental questions, which should be considered by the user before he places an order for a SAW resonator for a new application. Such a procedure will be the users insurance against unsatisfactory performance. Standard specifications,
26、such as those of the IEC of which this guide forms a part, and national specifications or detail specifications issued by manufacturers, will define the available combinations of resonance frequency, quality factor, motional resistance, parallel capacitance, etc. These specifications are compiled to
27、 include a wide range of SAW resonators with standardized performances. It cannot be over-emphasized that the user should, wherever possible, select his SAW resonators from these specifications, when available, even if it may lead to making small modifications to his circuit to enable the use of sta
28、ndard resonators. This applies particularly to the selection of the nominal frequency. 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
29、 the referenced document (including any amendments) applies. IEC 61019-1:2004, Surface acoustic wave (SAW) resonators Part 1: Generic specification IEC 61019-3:1991, Surface acoustic wave (SAW) resonators Part 3: Standard outlines and lead connections 3 Technical considerations It is of prime intere
30、st to a user that the resonator characteristics should satisfy particular specifications. The selection of oscillating circuits and SAW resonators to meet such specifications should be a matter of agreement between user and manufacturer. Resonator characteristics are usually expressed in terms of re
31、sonance frequency, motional resistance, quality factor and parallel capacitance (for the one-port type) and centre frequency, insertion attenuation, loaded and unloaded quality factor, input capacitance and output capacitance (for the two-port type). A standard method for measuring resonator charact
32、eristics is described in 8.5 and 8.6 of IEC 61019-1. The specifications are to be satisfied between the lowest and highest temperatures of the specified operating temperature range and before and after environmental tests. EN 61019-2:2005 6 4 Fundamentals of SAW resonators 4.1 Basic structure SAW re
33、sonators consist of interdigital transducers (IDT) and of grating reflectors, which are placed on the surface of a piezoelectric substrate. In most cases, the grating reflectors are made of thin metal (such as Al, Au) film while, in some cases, they are constructed with periodic grooves. The die is
34、bonded by an adhesive agent into a sealed enclosure, and the IDT is electrically connected to the terminals with bonding wires. There are two SAW resonator configurations. One is a one-port SAW resonator. The other is a two-port SAW resonator. The former has a single IDT between two reflectors, as s
35、hown in Figure 1. The latter has two IDTs between two reflectors, as shown in Figure 2. In the figures, effl is the resonator cavity length, as described in 5.2 c). leffS d = 0/2 Grating reflector Grating reflector IDT IEC 694/05 Figure 1 One-port SAW resonator configuration leffS d = 0/2 Grating re
36、flector Grating reflector IDT IEC 695/05 Figure 2 Two-port SAW resonator configuration 4.2 Principle of operation The resonance phenomenon for SAW resonators is achieved by confining the SAW vibration energy within grating reflectors. The SAW, excited by an alternating electrical field between IDT e
37、lectrode fingers, propagates outside the IDT to be reflected by grating reflectors. EN 61019-2:2005 7 The grating reflectors feed the perturbation to the SAW, owing to the discontinuity in electrical or mechanical impedance. When the SAW is incident on such grating reflectors, the incident wave is g
38、radually converted into a reflected wave. Although the amount of perturbation per unit reflective element may be very small, a large number of such elements, arranged periodically, reflect the SAW in phase, and maximize coherent reflection. These grating configurations can form effective reflecting
39、boundary, creating a standing wave between the reflectors and make resonance with a very high Q. Figure 3 shows the displacement distribution for this standing wave for a one-port SAW resonator. As shown in the figure, the SAW energy is maximum near the centre of the IDT, and gradually decays toward
40、s the edges of the grating reflectors. The resonance frequency, fr, is approximately determined by fr vs/(2d) = vs/0where vs is the SAW propagation velocity; d is the distance between electrode centres; 0is the SAW wavelength at the stop band centre frequency. d SAW energy distribution Grating refle
41、ctor IDT Grating reflector Substrate IEC 696/05 Figure 3 Standing wave pattern and SAW energy distribution 5 SAW resonator characteristics 5.1 Reflector characteristics The reflector for SAW resonators consists of a periodically arranged array of reflective elements, called a grating reflector. As c
42、ross-sections show in Figure 4, possible array elements are: a) metal strips or dielectric ridges; b) grooves; c) ion-implanted or metal-diffused strips. For example, an aluminum strip on ST-cut quartz, whose thickness h is 1 % of wave length (h/0) and whose width w is half the spatial period (w = d
43、/2 = 0/4), has a small reflection coefficient of approximately 0,5 %. A groove with 1 % depth has almost the same . This periodic perturbation causes efficient reflection of SAW energy, if its wavelength equals twice its periodicity. EN 61019-2:2005 8 dhIEC 697/05 4a Metal strips or dielectric ridge
44、s IEC 698/05 4b Grooves IEC 699/05 4c Ion-implanted or metal diffused strips Figure 4 Grating reflector configurations A grating reflector without loss with a finite number of array elements has a frequency range of nearly total reflection called the stop band. The fractional stop bandwidth to centr
45、e frequency is 2/, where is the reflection coefficient for one element. Figure 5 indicates the frequency dependency on the total reflectivity | for the grating reflector with a finite number NR of array elements. Theoretically, the reflectivity maximum value is derived as: |max= tanh(NR ) at the cen
46、tre frequency f0 of the stop band. A greater reflectivity makes SAW resonator Q value higher, due to decreasing the leakage of SAW energy stored in the cavity between two grating reflectors. EN 61019-2:2005 9 1,0 0,5 0,0 4 2 0 2 4 NR = 2 / Frequency (f f0) f0Reflection coefficient| IEC 700/05 Figure
47、 5 Reflectivity response for grating reflection For obtaining a greater reflectivity, it is clear, from the preceding equation, that NR should be larger. Increasing reflector element number NR is the easiest way to obtain a higher reflectivity. However, in practice, a greater element number, i.e. lo
48、nger reflector size, requires a larger SAW chip size and means an expensive SAW resonator. Generally, NR = 4 is adequate for practical SAW resonators. For obtaining greater reflectivity, increasing the reflection from one element is also effective. To accomplish this, strips should be thicker or gro
49、oves should be deeper. For the most part, is proportional to the thickness or the depth h/0. Thicker strips or deeper grooves require less element number NR for the same reflection coefficient and realize greater stop bandwidth. However, a reflector with a large h/0has the following disadvantages: a) the mode conversion loss from SAW to bulk wave tends to increase, which may degrade the quality factor; b) stopband centre frequency deviation fro
