1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationRadio frequency (RF) bulkacoustic wave (BAW) filters of assessed qualityPart 2: Guidelines for the useBS EN 62575-2:2012National forewordThis British Standard is the UK implement
2、ation of EN 62575-2:2012. It isidentical to IEC 62575-2:2012.The UK participation in its preparation was entrusted to Technical CommitteeEPL/49, Piezoelectric devices for frequency control and selection.A list of organizations represented on this committee can be obtained onrequest to its secretary.
3、This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 65875 4ICS 31.140Compliance with a British Standard cannot confer imm
4、unity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 31 October 2012.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 62575-2:2012EUROPEAN STANDARD EN 62575-2 NORME EUROPENNE EUROPISCHE
5、 NORM September 2012 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2012 CENELEC - All rights of exploitation in any form and by an
6、y means reserved worldwide for CENELEC members. Ref. No. EN 62575-2:2012 E ICS 31.140 English version Radio frequency (RF) bulk acoustic wave (BAW) filters of assessed quality - Part 2: Guidelines for the use (IEC 62575-2:2012) Filtres radiofrquences (RF) ondes acoustiques de volume (OAV) sous assur
7、ance de la qualit - Partie 2: Lignes directrices demploi (CEI 62575-2:2012) Volumenwellenfilter fr Hochfrequenzanwendungen (HFBAW-Filter) - Teil 2: Leitfaden fr die Anwendung (IEC 62575-2:2012) This European Standard was approved by CENELEC on 2012-08-29. CENELEC members are bound to comply with the
8、 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 CEN-CENELEC Management
9、 Centre 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 CEN-CENELEC Management Centre has the same
10、status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithu
11、ania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 62575-2:2012EN 62575-2:2012 - 2 - Foreword The text of document 49/994/FDIS, future edition 1 of IEC 62575-2, prepared by IEC/TC 49 “Piezo
12、electric, dielectric and electrostatic devices and associated materials for frequency control, selection and detection“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62575-2:2012. The following dates are fixed: latest date by which the document has to be implemented at
13、 national level by publication of an identical national standard or by endorsement (dop) 2013-05-29 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2015-08-29 Attention is drawn to the possibility that some of the elements of this document may be
14、the subject of patent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 62575-2:2012 was approved by CENELEC as a European Standard without any modification. In the official version, f
15、or Bibliography, the following notes have to be added for the standards indicated: IEC 60862-1:2003 NOTE Harmonised as EN 60862-1:2003 (not modified). IEC 62047-7:2011 NOTE Harmonised as EN 62047-7:2011 (not modified). BS EN 62575-2:2012 2 62575-2 IEC:2012 CONTENTS INTRODUCTION . 5 1 Scope . 6 2 Nor
16、mative references . 6 3 Technical considerations 6 4 Fundamentals of RF BAW filters . 7 4.1 General . 7 4.2 Fundamentals of RF BAW resonators 8 4.3 RF resonator structures . 13 4.4 Ladder filters . 15 4.4.1 Basic structure 15 4.4.2 Principle of operation . 16 4.4.3 Characteristics of ladder filters
17、17 5 Application guide 18 5.1 Application to electronics circuits. 18 5.2 Availability and limitations . 18 5.3 Input levels 18 6 Practical remarks 18 6.1 General . 18 6.2 Feed-through signals . 19 6.3 Load and source impedance conditions . 19 7 Miscellaneous 19 7.1 Soldering conditions 19 7.2 Stati
18、c electricity . 19 8 Ordering procedure 19 Bibliography 22 Figure 1 Frequency response of a RF BAW filter 7 Figure 2 Applicable range of frequency and relative bandwidth of the RF BAW filter and the other filters . 8 Figure 3 Basic BAW resonator structure. 9 Figure 4 BVD model . 9 Figure 5 Typical i
19、mpedance characteristics 10 Figure 6 Typical impedance characteristics of RF BAW devices . 12 Figure 7 Modified BVD model. 13 Figure 8 FBAR structures . 14 Figure 9 SMR structure 15 Figure 10 Structure of ladder filter . 15 Figure 11 Equivalent circuit of basic section of ladder filter 16 Figure 12
20、Basic concept of ladder filter 16 Figure 13 Typical characteristics of a 1,9 GHz range ladder filter . 17 BS EN 62575-2:201262575-2 IEC:2012 5 INTRODUCTION RF BAW filters are now widely used in mobile communications. While the RF BAW filters have various specifications, many of them can be classifie
21、d within a few fundamental categories. Standard specifications, given in IEC 62575, and national specifications or detail specifi-cations issued by manufacturers, define the available combinations of nominal frequency, pass bandwidth, ripple, shape factor, terminating impedance, etc. These specifica
22、tions are compiled to include a wide range of RF BAW filters with standardized performances. It cannot be over-emphasized that the user should, wherever possible, select his RF BAW filters from these specifications, when available, even if it may lead to making small modifications to his circuit to
23、enable standard filters to be used. This applies particularly to the selection of the nominal frequency. This standard has been compiled in response to a generally expressed desire on the part of both users and manufacturers for guidance on the use of RF BAW filters, so that the filters may be used
24、to their best advantage. To this end, general and fundamental characteristics have been explained in this part of IEC 62575. It is not the aim of this standard to explain theory, nor to attempt to cover all the eventualities which may arise in practical circumstances. This standard draws attention t
25、o some of the more fundamental questions, which should be considered by the user before he places an order for an RF BAW filter for a new application. Such a procedure will be the users insurance against unsatisfactory performance. BS EN 62575-2:2012 6 62575-2 IEC:2012 RADIO FREQUENCY (RF) BULK ACOU
26、STIC WAVE (BAW) FILTERS OF ASSESSED QUALITY Part 2: Guidelines for the use 1 Scope This part of IEC 62575 gives practical guidance on the use of RF BAW filters which are used in telecommunications, measuring equipment, radar systems and consumer products. General information, standard values and tes
27、t conditions will be provided in a future IEC standard1. This part of IEC 62575 includes various kinds of filter configurations, of which the operating frequency range is from approximately 500 MHz to 10 GHz and the relative bandwidth is about 1 % to 5 % of the centre frequency. 2 Normative referenc
28、es The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. None
29、. 3 Technical considerations It is of prime interest to a user that the filter characteristics should satisfy a particular specification. The selection of tuning networks and RF BAW filters to meet that specification should be a matter of agreement between user and manufacturer. Filter characteristi
30、cs are usually expressed in terms of insertion attenuation as a function of frequency, as shown in Figure 1. A standard method for measuring insertion attenuation is described in IEC 60862-1:2003, 5.5.2. Insertion attenuation characteristics are further specified by nominal frequency, minimum insert
31、ion attenuation or maximum insertion attenuation, pass-band ripple and shape factor. The specification is to be satisfied between the lowest and highest temperatures of the specified operating temperature range and before and after environmental tests. _ 1This standard (under consideration) is expec
32、ted to bear the reference number IEC 62575-1. BS EN 62575-2:201262575-2 IEC:2012 7 Figure 1 Frequency response of a RF BAW filter 4 Fundamentals of RF BAW filters 4.1 General The features of RF BAW filters are their small size, light weight, adjustment-free, high stability and high reliability. RF B
33、AW filters add new features and applications to the field of surface acoustic wave (SAW) filters and dielectric resonator filters. Nowadays, RF BAW filters with low insertion attenuation are widely used in various applications in the gigahertz range. RF BAW filters are becoming rapidly popular as mi
34、niature and low insertion attenuation filters for mobile communication application. RF BAW resonator filters can realize low insertion attenuation easily and of a smaller size than that of the RF SAW filters with the same bandwidth. Their feasible bandwidth is, however, limited by employing piezoele
35、ctric materials, design methods and so on. It is desirable for users to understand these factors for RF BAW resonator filters. This standard explains the principles and characteristics of RF BAW resonator filters. RF BAW filters usually employ a filter configuration called the ladder filter, which i
36、s composed of multiple RF BAW resonators. They are classified into two types: film bulk acoustic resonators and solidly mounted resonators. In Figure 2, the applicable frequency range and relative bandwidth of the RF BAW filters are shown in comparison with those of ceramic, crystal, dielectric, hel
37、ical, SAW and stripline filters. Frequency (GHz) Pass-band ripple Specified stop-band relative attenuation Minimum insertion attenuation Nominal insertion attenuation Reference frequency Centre Cut-off Cut-off Attenuation 0 Specified pass-band Attenuation(dB)IEC 1444/12 BS EN 62575-2:2012 8 62575-2
38、IEC:2012 Figure 2 Applicable range of frequency and relative bandwidth of the RF BAW filter and the other filters 4.2 Fundamentals of RF BAW resonators a) Acoustic resonance When a mechanical impact is applied to a solid surface, acoustic waves are generated, and a portion of their energy is transmi
39、tted by propagation of the acoustic waves in the bulk. This type of wave is called the bulk acoustic wave (BAW). Remaining energy may be transferred by acoustic waves propagating along the surface. This type of wave is called the surface acoustic wave (SAW). There are two types of BAWs: the longitud
40、inal or dilatational BAW, with the displacement toward the propagation direction, and the transverse or shear BAW, with the displacement normal to the propagation direction. Acoustic wave velocities in solids are a few hundreds of meters per second to twenty thousands of meters per second. Usually t
41、he longitudinal BAW is few times faster than the shear BAW for a given material and orientation. In the case of acoustic wave propagation in a parallel plate, it is known that the plate causes a mechanical resonance (thickness resonance) when the plate thickness h is half-integer times the wavelengt
42、h of acoustic waves propagating in the plate normal to the plate surface, i.e. 2nh = , where n is an integer and called the order of modes. We obtain mechanical resonance frequencies fras )2(rhnVVf = (1) where V is the acoustic wave velocity. Equation (1) indicates that in addition to a lowest-order
43、 resonance (n=1) called the fundamental resonance, a series of higher-order (n1) ones might be excited. Since frfor n1 will be integer times frfor n=1 in this case, higher-order resonances are often called harmonics or harmonic resonances. When the longitudinal BAW is responsible for the thickness r
44、esonance, it is called the thickness extensional (TE) resonance but when the shear wave is responsible, it is called the thickness shear (TS) resonance. Stripline filters Relativebandwidth(%)Dielectric filters Crystal filters Ceramic filters Helical filters SAW filters Frequency (Hz) 1 M 10 M 100 M
45、1 G 10 G 100 G 103102101100101102RF BAW filters IEC 1445/12 BS EN 62575-2:201262575-2 IEC:2012 9 There are also acoustic waves propagating along the plate top surface. When wave energy is well confined near the top surface and influence of the back surface is negligible, the waves are called the sur
46、face acoustic waves (SAWs). On the other hand, when wave energy penetrates into the plate and influence of the back surface is not negligible, the waves are called plate waves or Lamb waves. b) Piezoelectric excitation and detection In the case where a piezoelectric plate is sandwiched between two p
47、arallel electrodes (see Figure 3), when an electrical voltage E is applied between two electrodes, mechanical force is generated through the piezoelectricity, and acoustic motion will be induced. On the other hand, electrical charges will be induced to the electrodes by electric fields associated wi
48、th propagating acoustic waves. Figure 3 Basic BAW resonator structure An electromechanical equivalent circuit shown in Figure 4 may be deduced from these relations. In Figure 4, C0is the clumped capacitance originating from the electrostatic coupling between two electrodes, and C1,L1and R1are the mo
49、tional capacitance, inductance and resistance, respectively, originating from mechanical reaction, i.e. elasticity, inertia and damping, respectively. This circuit is called the Butterworth-Van Dyke (BVD) model. Figure 4 BVD model Figure 4 implies that mechanical resonances described above can be excited and detected electrically through the electrodes. Namely, this device serves as an electrical resonator. This type of resonator is called
