SIST EN 61337-2:2005

Filters using waveguide type dielectric resonators -- Part 2: Guidance for use

Draws attention to some of the more fundamental questions which should be considered by the user before he places an order for dielectric filters for a new application. Is limited to filters using waveguide type dielectric resonators that are used for microwave applications such as portable phones, cellular base stations and radio links.

Filter mit dielektrischen Resonatoren vom Wellenleitertyp -- Teil 2: Leitfaden zur Anwendung

Filtres utilisant des résonateurs diélectriques à modes guidés -- Partie 2: Guide d'utilisation

Draws attention to some of the more fundamental questions which should be considered by the user before he places an order for dielectric filters for a new application. Is limited to filters using waveguide type dielectric resonators that are used for microwave applications such as portable phones, cellular base stations and radio links.

Filtri z dielektričnimi resonatorji valovodnega tipa – 2. del: Navodilo za uporabo (IEC 61337-2:2004)

General Information

• Status: Published
• Publication Date: 30-Nov-2005
• ICS: 31.140 - Piezoelectric devices
• ICS: 31.160 - Electric filters
• 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-Dec-2005
• Due Date: 01-Dec-2005
• Completion Date: 01-Dec-2005
• Ref Project: EN 61337-2:2004 - Filters using waveguide type dielectric resonators - Part 2: Guidance for use

Standards Content (Sample)

SLOVENSKI SIST EN 61337-2:2005
STANDARD
december 2005
Filtri z dielektričnimi resonatorji valovodnega tipa – 2. del: Navodilo za
uporabo (IEC 61337-2:2004)

Filters using waveguide type dielectric resonators – Part 2: Guidance for use (IEC

61337-2:2004)
ICS 31.140; 31.160 Referenčna številka
SIST EN 61337-2:2005(en)

© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD EN 61337-2
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2004
ICS 31.140
English version
Filters using waveguide type dielectric resonators
Part 2: Guidance for use
(IEC 61337-2:2004)
Filtres utilisant des résonateurs Filter mit dielektrischen Resonatoren
diélectriques à modes guidés vom Wellenleitertyp
Partie 2: Guide d'utilisation Teil 2: Leitfaden zur Anwendung
(CEI 61337-2:2004) (IEC 61337-2:2004)

This European Standard was approved by CENELEC on 2004-09-01. 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, Cyprus, Czech

Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,

Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61337-2:2004 E
---------------------- Page: 2 ----------------------
EN 61337-2:2004 - 2 -
Foreword

The text of document 49/665/FDIS, future edition 1 of IEC 61337-2, prepared by IEC TC 49,

Piezoelectric and dielectric devices for frequency control and selection, was submitted to the

IEC-CENELEC parallel vote and was approved by CENELEC as EN 61337-2 on 2004-09-01.

The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2005-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-09-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 61337-2:2004 was approved by CENELEC as a European

Standard without any modification.
__________
---------------------- Page: 3 ----------------------
- 3 - EN 61337-2:2004
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.
Publication Year Title EN/HD Year
IEC 60068-1 1988 Environmental testing EN 60068-1 1994
Part 1: General and guidance
IEC 60068-2-1 1990 Part 2: Tests - Tests A: Cold EN 60068-2-1 1993
IEC 60068-2-2 1974 Part 2: Tests - Tests B: Dry heat EN 60068-2-2 1993
IEC 60068-2-6 1995 Part 2: Tests - Test Fc: Vibration EN 60068-2-6 1995
(sinusoidal)
IEC 60068-2-7 1983 Part 2: Tests - Test Ga: Acceleration, EN 60068-2-7 1993
steady state
IEC 60068-2-13 1983 Part 2: Tests - Test M: Low air pressure EN 60068-2-13 1999
IEC 60068-2-14 1984 Part 2: Tests - Test N: Change of EN 60068-2-14 1999
temperature
IEC 60068-2-20 1979 Part 2: Tests - Test T: Soldering HD 323.2.20 S3 1988
IEC 60068-2-21 1999 Part 2-21: Tests - Test U: Robustness of EN 60068-2-21 1999
terminations and integral mounting
devices
IEC 60068-2-27 1987 Part 2: Tests - Test Ea and guidance: EN 60068-2-27 1993
Shock
IEC 60068-2-30 1980 Part 2: Tests - Test Db and guidance: EN 60068-2-30 1999
Damp heat, cyclic (12 + 12-hour cycle)
EN 60068-1 includes corrigendum October 1988 + A1:1992 to IEC 60068-1.
EN 60068-2-2 includes suppplement A:1976 to IEC 60068-2-2.
EN 60068-2-7 includes A1:1986 to IEC 60068-2-7.
EN 60068-2-14 includes A1:1986 to IEC 60068-2-14.
HD 323.2.20 S3 includes A2 :1987 to IEC 60068-2-20.
EN 60068-2-30 includes A1:1985 to IEC 60068-2-30.
---------------------- Page: 4 ----------------------
EN 61337-2:2004 - 4 -
Publication Year Title EN/HD Year
IEC 60068-2-58 1999 Part 2-58: Tests - Test Td: Test methods EN 60068-2-58 1999
for solderability, resistance to dissolution
of metallization and to soldering heat of
surface mounting devices (SMD)
IEC 60068-2-78 2001 Part 2-78: Tests - Test Cab: Damp heat, EN 60068-2-78 2001
steady state
IEC 61337-1-1 - Filters using waveguide type dielectric - -
resonators
Part 1: General information, standard
values and test conditions -- Section 1:
General information and standard values
IEC 61337-1-2 - Filters using waveguide type dielectric - -
resonators
Part 1-2: Test conditions

EN 60068-2-58 is superseded by EN 60068-2-58:2004, which is based on IEC 60068-2-58:2004.

Undated reference.
---------------------- Page: 5 ----------------------
INTERNATIONAL IEC
STANDARD 61337-2
First edition
2004-07
Filters using waveguide type
dielectric resonators –
Part 2:
Guidance for use
© IEC 2004 ⎯ Copyright - all rights reserved

No part of this publication may be reproduced or utilized in any form or by any means, electronic or

mechanical, including photocopying and microfilm, without permission in writing from the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch

PRICE CODE
Commission Electrotechnique Internationale U
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
For price, see current catalogue
---------------------- Page: 6 ----------------------
– 2 – 61337-2 © IEC:2004(E)
CONTENTS

FOREWORD...........................................................................................................................4

INTRODUCTION.....................................................................................................................6

1 Scope...............................................................................................................................7

2 Normative references .......................................................................................................7

3 Application guide for filters using waveguide type dielectric resonators ............................8

3.1 Classification of filters using waveguide type dielectric resonators ..........................8

3.2 Practical remarks for filters using waveguide type dielectric filters...............................9

3.2.1 TE mode dielectric filter..........................................................................9

01δ

3.2.2 TM mode dielectric filter ............................................................................13

3.2.3 TEM mode coaxial dielectric filter ..............................................................15

3.2.4 Chip-type multilayered dielectric filter ........................................................17

3.2.5 Stripline and microstripline dielectric filters................................................20

4 Checklist of dielectric resonator specification .................................................................24

4.1 Checklist ...............................................................................................................24

Bibliography..........................................................................................................................26

Figure 1 – Typical unloaded Q and maximum operating power of dielectric filters ..................9

Figure 2 – Example of practically equivalent unloaded Q of a TE mode dielectric
01δ

filter compared with a TE mode metal cavity filter............................................................10

101

Figure 3 – Example of a TE mode dielectric band-pass filter............................................11

01δ

Figure 4 – Example of a TE mode dielectric band-stop filter ............................................11

01δ

Figure 5 – Example of spurious responses for the TE mode dielectric band-pass filter.....12

01δ
Figure 6 – Example of a TE mode dielectric band-pass filter with quarter
01δ

wavelength coaxial resonators ..............................................................................................12

Figure 7 – TM and TM mode dielectric resonators .....................................................13

010 110

Figure 8 – Example of the third-harmonic distortion level of dielectric resonator

material at 800 MHz..............................................................................................................14

Figure 9 – Example of an antenna filter and an antenna duplexer for cellular base stations 14

Figure 10 – Practically obtained unloaded Q of quarter wavelength TEM mode
dielectric resonators with an ε’ of 20, 40 and 90 (outer diameter = 3 mm; inner

diameter = 1 mm; practical conductivity of shielding conductor = 4,8 × 10 [S/m]) ................16

Figure 11 – Examples of antenna duplexers for portable phones using a TEM mode

dielectric resonator ...............................................................................................................16

Figure 12 – Examples of the attenuation characteristics of a block-type duplexer for a

wideband CDMA portable phone...........................................................................................17

Figure 13 – Example of a chip-type multilayered dielectric band-pass filter ...........................18

Figure 14 – Example of the attenuation characteristics of a chip-type multilayered

dielectric filter .......................................................................................................................19

Figure 15 – Schematic configurations of stripline and microstripline dielectric filter..............20

Figure 16 – Example of the conductor pattern and attenuation characteristic of a

parallel-coupled band-pass stripline filter ..............................................................................22

---------------------- Page: 7 ----------------------
61337-2 © IEC:2004(E) – 3 –

Figure 17 – Example of the conductor pattern and attenuation characteristic of an

interdigital band-pass stripline filter ......................................................................................22

Figure 18 – Example of the conductor pattern and attenuation characteristic of a

comb-line band-pass stripline filter........................................................................................23

Figure 19 – Example of the conductor pattern and attenuation characteristic of a band-

stop stripline filter .................................................................................................................23

Table 1 – References to relevant publications......................................................................24

---------------------- Page: 8 ----------------------
– 4 – 61337-2 © IEC:2004(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
––––––––––––
FILTERS USING WAVEGUIDE TYPE DIELECTRIC RESONATORS –
Part 2: Guidance for use
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,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). 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. 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 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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

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 61337-2 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
49/665/FDIS 49/683/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.

---------------------- Page: 9 ----------------------
61337-2 © IEC:2004(E) – 5 –

IEC 61337 consists of the following parts under the general title Filters using waveguide type

dielectric resonators:
Part 1: Generic specification;

Part 1-1: General information, standard values and test conditions – General information

and standard values;

Part 1-2: General information, standard values and test conditions − Test conditions;

Part 2: Guidance for use;
Part 3: Standard outlines .

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

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version may be issued at a later date.
___________
To be published.
To be merged and replaced by IEC 61337-1 in the near future.
Under consideration.
---------------------- Page: 10 ----------------------
– 6 – 61337-2 © IEC:2004(E)
INTRODUCTION

This part of IEC 61337 gives practical guidance on the use of filters using waveguide type

dielectric resonators that are used in telecommunications and radar systems. Refer to

IEC 61337-1-1 and IEC 61337-1-2 for general information, standard values and test

conditions.

These dielectric filters have the features of small size, low loss, high reliability and high

stability against temperature and ageing. Dielectric filters are suitable for applications such as

mobile communication service, mobile satellite communication service, microwave terrestrial

communication service, and fixed satellite communication service. In particular, they are now

widely used for duplexers and filters of portable phones and cellular base stations.

This standard has been compiled in response to a generally expressed desire on the part of

both users and manufacturers for guidance for the use of filters using waveguide type

dielectric resonators, so that the filters may be used to their best advantage. For this purpose,

general and fundamental characteristics have been explained in this standard.
---------------------- Page: 11 ----------------------
61337-2 © IEC:2004(E) – 7 –
FILTERS USING WAVEGUIDE TYPE DIELECTRIC RESONATORS –
Part 2: Guidance for use
1 Scope

The scope of this part of IEC 61337 is limited to filters using waveguide type dielectric

resonators that are used for microwave applications such as portable phones, cellular base

stations and radio links.

It is not the aim of this standard either to explain the theory or to attempt to cover all the

eventualities that may arise in practical circumstances. This standard draws attention to some

of the more fundamental questions which should be considered by the user before he places

an order for dielectric filters for a new application. Such a procedure will be the user's

insurance against unsatisfactory performance.

Standard specifications, such as those given in IEC 61337, and national specifications or

detail specifications issued by manufacturers, will define the available combinations of mid-

band frequency, pass band, insertion attenuation, pass-band ripple, return attenuation,

spurious response, operating power, and so on. These specifications are compiled to include

a wide range of dielectric filters with standardized performances. It cannot be over-

emphasized that the user should, wherever possible, select his dielectric filters from these

specifications, when available, even if it involves making small modifications to his circuit to

enable standard filters to be used.
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 60068-1:1988, Environmental testing – Part 1: General and guidance
IEC 60068-2-1:1990, Environmental testing – Part 2: Tests. Tests A – Cold
IEC 60068-2-2:1974, Environmental testing – Part 2: Tests. Tests B – Dry heat

IEC 60068-2-6:1975, Environmental testing – Part 2: Tests. Test Fc: Vibration (sinusoidal)

IEC 60068-2-7:1983, Environmental testing – Part 2: Tests. Test Ga: Acceleration, steady

state

IEC 60068-2-13:1983, Environmental testing – Part 2: Tests. Test M: Low air pressure

IEC 60068-2-14:1984, Environmental testing – Part 2: Tests. Test N: Change of temperature

IEC 60068-2-20:1979, Environmental testing – Part 2: Tests. Test T: Soldering

IEC 60068-2-21:1999, Environmental testing – Part 2-21: Tests – Test U: Robustness of

terminations and integral mounting devices
---------------------- Page: 12 ----------------------
– 8 – 61337-2 © IEC:2004(E)

IEC 60068-2-27:1987, Environmental testing – Part 2: Tests. Test Ea and guidance: Shock

IEC 60068-2-30:1980, Environmental testing – Part 2: Tests. Test Db and guidance: Damp

heat, cyclic (12 + 12-hour cycle)

IEC 60068-2-58:1999, Environmental testing – Part 2-58: Tests – Test Td – Test methods for

solderability, resistance to dissolution of metallization and to soldering heat of surface

mounting devices (SMD)

IEC 60068-2-78:2001, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat,

steady state

IEC 61337-1-1, Filters using waveguide type dielectric resonators − Part 1-1: General

information, standard values and test conditions – General information and standard values

IEC 61337-1-2, Filters using waveguide type dielectric resonators – Part 1-2: General

information, standard values and test conditions – Test conditions
3 Application guide for filters using waveguide type dielectric resonators
3.1 Classification of filters using waveguide type dielectric resonators

Filters using waveguide type dielectric resonators are classified into six types: TE mode

01δ

dielectric filter, TM mode dielectric filter, TEM mode coaxial dielectric filter, stripline and

microstripline dielectric filter, and multilayered chip-type filter.

These dielectric filters are classified according to their operating power and the unloaded Q

of their resonance mode. Figure 1 shows the relationship between the unloaded Q and the

maximum power durability for these filters in practical applications.

High-power durability of up to 100 W is the advantage of dielectric filters. The maximum

operating power, however, should be limited by the construction of filters and by the Q value

of the dielectric resonator used for the filters, because higher operating power causes a

temperature rise that results in inferior electric characteristics such as a shift of mid-band

frequency and an increase in insertion attenuation.
---------------------- Page: 13 ----------------------
61337-2 © IEC:2004(E) – 9 –
Multi-layered chip-type filter
Stripline and microstripline filter
TM mode filter
100
TE mode filter
TEM mode
filter
0,1
10 100 1 000 10 000 100 000
Unloaded quality factor (Q)
IEC 850/04

Figure 1 ದದದದ Typical unloaded Q and maximum operating power of dielectric filters

3.2 Practical remarks for filters using waveguide type dielectric filters
3.2.1 TE mode dielectric filter
01δδ
a) Features of the TE mode dielectric filter
01δ
The TE mode resonator obtains very high unloaded Q, as most of the resonance
01δ

energy is stored in the dielectric element, and the copper loss due to the resistivity of the

shielding conductor is minimized.

Figure 2 shows an example of the practically equivalent unloaded Q for the TE mode

01δ

dielectric filter compared with the TE mode metal cavity. High unloaded Q from 5 000

101

to 10 000 is obtained by using high Q dielectric resonator materials with characteristics

such as an ε’ of 30 and a Q × f value of 150 000 GHz, or an ε’ of 25 and a Q × f value of

300 000 GHz.

Using these TE mode dielectric resonators, miniaturized dielectric filters with low

01δ

insertion attenuation and high temperature stability are realized at the frequency range

from 1 GHz to 20 GHz. The relative bandwidth of the TE mode dielectric band-pass
01δ
filter is usually less than 1 % of the mid-band frequency.
Maximum power durability W
---------------------- Page: 14 ----------------------
– 10 – 61337-2 © IEC:2004(E)
20 000
ε’ = 25
ε’ = 30
10 000
5 000
TE metal cavity filter
101
2 000
2 5 10 20
Frequency GHz
IEC 851/04
Figure 2 – Example of practically equivalent unloaded Q of a TE mode dielectric
01δδδδ
filter compared with a TE mode metal cavity filter
101
Unloaded Q
---------------------- Page: 15 ----------------------
61337-2 © IEC:2004(E) – 11 –
b) Construction of the TE mode dielectric filter
01δ

Figure 3 shows an example of the TE mode dielectric band-pass filter. Plural pieces of

01δ
columnar or cylindrical dielectric resonators are fixed in a metal case.

The dimensions a and b of the filter are determined to constitute the cut-off waveguide of

the dominant TE mode. The adjustment of the mid-band frequency by the trimming

screw is less than 1 % of the mid-band frequency for the dielectric filter, while the

adjustment of the mid-band frequency for the TE mode waveguide filter is 5 %.
101

Figure 4 shows an example of the TE mode dielectric band-stop filter. The columnar or

01δ

cylindrical dielectric resonators are coupled with the microstrip line. The resonators are

fixed at the three-quarters wavelength interval along the microstrip line.

The high unloaded Q of the dielectric resonators realizes the narrow bandwidth and the

low insertion loss in the neighbouring frequency of the rejection band of the TE mode

01δ
dielectric band-stop filter.
Connector
Frequency tuning screw
Dielectric resonator
Dielectric support
IEC 852/04
Figure 3 – Example of a TE mode dielectric band-pass filter
01δδδδ
Frequency tuning screw
Connector
Microstripline
Dielectric resonator
IEC 853/04
Figure 4 – Example of a TE mode dielectric band-stop filter
01δδδδ
---------------------- Page: 16 ----------------------
– 12 – 61337-2 © IEC:2004(E)
c) Characteristics of the TE mode dielectric filter
01δ
In the case of the TE mode dielectric filter, deterioration of the attenuation
01δ

characteristics are caused by the unnecessary spurious resonances that exist over

1,2 times the mid-band frequency.

Figure 5 shows an example of the spurious response of the TE mode dielectric band-

01δ

pass filter. This spurious response can be suppressed by using the quarter wavelength

coaxial resonance elements for the first and last resonators of the filter. Figure 6 shows an

example of the filter with the coaxial resonance elements.
Without coaxial resonators
With coaxial resonators
6 8 10 12 14
Frequency GHz
IEC 854/04

Figure 5 – Example of spurious responses for the TE mode dielectric band-pass filter

01δδδδ
Connector
Frequency tuning screw
Coaxial resonator
b Dielectric resonator
IEC 855/04
Figure 6 – Example of a TE mode dielectric band-pass filter
01δδ
with quarter wavelength coaxial resonators
Insertion attenuation dB
---------------------- Page: 17 ----------------------
61337-2 © IEC:2004(E) – 13 –
3.2.2 TM mode dielectric filter
a) Features of the TM mode dielectric filter

Figure 7 shows the construction of the TM and the TM mode dielectric resonators.

010 110

These resonators are often used for high-power applications such as filters for cellular

base stations, due to the construction that aids in the release of heat.

As the electric field passes from the bottom to the top of the shielding conductor,

undesirable frequency shift is caused if the air gap arises between the dielectric and the

shielding conductor due to the difference of the thermal-expansion coefficients. To solve

this problem, the practical TM mode resonator and the shielding cavity are made of a

mono-block structure using the same dielectric material. The silver conductor is fired on

the surface of this dielectric cavity. This mono-block structure realizes high temperature

stability of the resonance frequency and high reliability for the release of heat.

The dielectric resonator materials used for the filters of cellular base stations must have

low tanδ to restrain the heat generation and low intermodulation distortion level to restrain

the interference between plural signals.
Electric field
Magnetic field
Shielding
conductor
Dielectric
resonator
IEC 856/04
IEC 857/04
Figure 7a ದ TM mode Figure 7b ದ TM mode
010 110
Figure 7 ದದ TM and TM mode dielectric resonators
010 110
---------------------- Page: 18 ----------------------
– 14 – 61337-2 © IEC:2004(E)

The materials with low tanδ have a low third-harmonic distortion level. Figure 8 shows the

third-harmonic distortion level at 800 MHz for three kinds of dielectric resonator materials.

(Zr,Sn)TiO material with an ε’ of 38 and a Q™ f value of 50 000 has the low distortion

level of –150 dBc at a field intensity of 50 V/mm, which can be used for filters of cellular

base stations.
b) Construction of the TM mode dielectric filter

Figure 9 shows examples of an antenna filter and an antenna duplexer for cellular base

stations. The antenna filter is made of six TM mode dielectric resonators.
110
E V/mm
E (V/mm)
IEC 858/04
Figure 8 ದದ Example of the third-harmonic distortion level
of dielectric resonator material at 800 MHz
Metal housing
Rx connector
Metal housing
Tx connector
Dielectric
tuning rod
Connector
Antenna port
TM dual mode resonator
110
TM Mode dielectric
...