Gyromagnetic materials intended for application at microwave frequencies Measuring methods for properties

Gyromagnetische Materialien für Mikrowellenanwendungen - Messverfahren zur Ermittlung der Eigenschaften

Matériaux gyromagnétiques destinés à des applications hyperfréquences - Méthodes de mesure des propriétés

Giromagnetne snovi za uporabo pri mikrovalovnih frekvencah - Merilne metode za določene lastnosti - Dopolnilo A1

Ta mednarodni standard opisuje metode za merjenje lastnosti, ki se uporabljajo za določitev polikristalnih mikrovalovnih feritov v skladu s standardom IEC 60392 in za splošno uporabo v tehnologiji feritov. Te merilne metode so namenjene za preiskave materialov, ki se običajno imenujejo feriti, za uporabo pri mikrovalovnih frekvencah.

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SIST EN 60556:2007/A1:2017
Gyromagnetic materials intended for application at microwave frequencies Measuring
methods for properties
Matériaux gyromagnétiques destinés à des applications hyperfréquences - Méthodes de
mesure des propriétés
Ta slovenski standard je istoveten z: EN 60556:2006/A1:2016
29.100.10 Magnetne komponente Magnetic components
SIST EN 60556:2007/A1:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60556:2007/A1:2017

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SIST EN 60556:2007/A1:2017



June 2016
ICS 29.100.10

English Version
Gyromagnetic materials intended for application at microwave
frequencies - Measuring methods for properties
(IEC 60556:2006/A1:2016)
Matériaux gyromagnétiques destinés à des applications Gyromagnetische Materialien für Mikrowellenanwendungen -
hyperfréquences - Méthodes de mesure des propriétés Messverfahren zur Ermittlung der Eigenschaften
(IEC 60556:2006/A1:2016) (IEC 60556:2006/A1:2016)
This amendment A1 modifies the European Standard EN 60556:2006; it was approved by CENELEC on 2016-05-05. CENELEC members
are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this amendment 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 Centre or to any CENELEC member.
This amendment 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 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,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 60556:2006/A1:2016 E

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SIST EN 60556:2007/A1:2017
EN 60556:2006/A1:2016
European foreword
The text of document 51/1064/CDV, future IEC 60556:2006/A1, prepared by IEC/TC 51 "Magnetic
components and ferrite materials" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 60556:2006/A1:2016.
The following dates are fixed:
(dop) 2017-02-05
• latest date by which the document has to be implemented at
national level by publication of an identical national
standard or by endorsement
(dow) 2019-05-05
• latest date by which the national standards conflicting with
the document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be 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 60556:2006/A1:2016 was approved by CENELEC as a
European Standard without any modification.

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SIST EN 60556:2007/A1:2017

IEC 60556


Edition 2.0 2016-03








Gyromagnetic materials intended for application at microwave frequencies –

Measuring methods for properties

Matériaux gyromagnétiques destinés à des applications hyperfréquences –

Méthodes de mesure des propriétés







ICS 29.100.10 ISBN 978-2-8322-3274-3

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

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

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SIST EN 60556:2007/A1:2017
– 2 – IEC 60556:2006/AMD1:2016
 © IEC 2016
This amendment has been prepared by IEC technical committee 51: Magnetic components
and ferrite materials.
The text of this amendment is based on the following documents:
CDV Report on voting
51/1064/CDV 51/1089A/RVC

Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website under
"" 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 document using a
colour printer.


Add, after Clause 11, the following new Clause 12 and Annex A:
12 Gyromagnetic resonance linewidth ΔH and effective gyromagnetic ratio γ
by non resonant method
12.1 General
So far the gyromagnetic resonance linewidth ΔH and the effective gyromagnetic ratio γ have
been measured by using the resonant cavity as described in Clause 6. Therefore, the
measuring frequency is restricted to the frequency specified by a cavity resonator.
Meanwhile, various kinds of ferrite devices have been developed in a wide frequency range.
Accordingly it is desirable to measure the gyromagnetic resonance linewidth ΔH and the
effective gyromagnetic ratio γ easily at any frequency demanded for the development of
ferrite materials or devices. Moreover, there are two problems in the cavity resonator method
described in Clause 6. One problem is the insufficient resolution of a magneto flux density
meter, which is apt to cause poor accuracy in the measurement of the narrow resonance

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SIST EN 60556:2007/A1:2017
IEC 60556:2006/AMD1:2016 – 3 –
© IEC 2016
linewidth. Another problem is that a ferrite sample becomes too small to be shaped into a
sphere or a disk, because it is necessary to reduce the size of a ferrite sample to keep the
resonance absorption increasing with the reduction of the resonance linewidth to proper
values in order to ensure a sufficiently small cavity perturbation. In Clause 12, the measuring
methods of the gyromagnetic resonance linewidth ΔH and the effective gyromagnetic ratio γ
at an arbitrary frequency are described.
12.2 Object
To describe methods that can be used for measuring the gyromagnetic resonance linewidth
ΔH and the effective gyromagnetic ratio γ of isotropic microwave ferrites at an arbitrary
frequency over the frequency range of 1 GHz to 10 GHz by the measurement of the changes
in transmission and reflection characteristics with frequency sweep.
12.3 Measuring methods
12.3.1 General
The measurements are performed by measuring the changes of transmission characteristics,
such as complex reflection coefficients or scalar transmission coefficients, in a transmission
line loaded with a ferrite sample with frequency sweep. The advent of a frequency synthesizer
and a receiver with low noise figure and a wide dynamic range in the microwave region has
made it possible to perform these measurements accurately.
Strictly speaking, the linewidth measured under frequency sweep and a constant external
magnetic field is not the same as the one measured under external magnetic field sweep and
a constant frequency as described in Clause 6. However the difference between two
measured values is small to the extent that it causes no problem in practical use.
As the measuring method, two methods can be considered as follows:
1) Reflection method – method measuring the reflection coefficients from the short-circuited
transmission line loaded with a ferrite sample.
2) Transmission method – method measuring the transmission power through a ferrite-
loaded coupling hole made in a common ground plane of the transmission lines crossing
at right angle.
These two methods have advantages and disadvantages in comparison with each other from
the standpoint of practical use. The reflection method has the advantage of a simple test
fixture’s structure, easier sample mounting and simpler measuring circuit arrangement due to
one port measurement, which is convenient for the measurement of temperature dependence
of the resonance linewidth. The transmission method has the advantage of being able to
measure the resonance linewidth by one ferrite sample in a wide frequency range and gives
more accurate measuring values of the resonance linewidth due to simpler measurement, i.e.
the measurement of the transmission power only, under careful making of a test fixture.
These two methods are enumerated in 12.3.2 and 12.3.3.
12.3.2 Reflection method Measurement theory
The recommended method for measuring the gyromagnetic resonance linewidth ΔH and
effective gyromagnetic ratio γ is based on the measurement of the reflection coefficient S
eff 11
of a short-circuited transmission line with the specimen as proposed by Bady [20]. In this
standard, the short-circuited microstrip line is used as schematically shown in Figure 27.

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SIST EN 60556:2007/A1:2017
– 4 – IEC 60556:2006/AMD1:2016
 © IEC 2016
Reference plane (virtual)
for µ = 1
for FMR
H cal

Short end

Figure 27 – Schematic drawing of short-circuited
microstrip line fixture with specimen
The reference plane is defined by the length of the specimen from the short end. Seen from
the reference plane of the test fixture, the lumped element equivalent circuit can be assumed
to be a L C parallel circuit as in Figure 28a) when the strong magnetic field is applied
o o
parallel to the plane of specimen (x-direction) to achieve the situation of µ = 1. After removing
this field, the field is applied perpendicularly to the specimen plane for gyromagnetic
resonance. Figure 28b) shows the equivalent circuit for gyromagnetic resonance [21], where
L is an air core inductance and C is a parasitic capacitance. The values of L and C are
o o o o
designated “fixture constants”. The method to calculate “fixture constants” is shown in When a gyromagnetic resonance occurs, it is considered that some portion η of air
core inductance L is replaced by the complex relative permeability µ’ µ”, and the coupling
coefficient η is almost invariable within the measurement frequency range. The half value
width of the resonant curve of the imaginary part µ” is defined as gyromagnetic resonance
linewidth. By measuring the S parameters of Figure 28a) and 28b), the quantity ηµ”L
11 o
proportional to the imaginary part µ” can be derived based on the circuit theory analysis as
shown in
Consequently the gyromagnetic resonance linewidth ∆H is derived from the resonance curve
of ηµ”L .
ηµ’L ηωµ”L
o o
S ←
S ←
(1 − η)L
o o o
a) b)

Figure 28a) with µ = 1 under strong magnetic
Figure 28b) with gyromagnetic resonance
field parallel to r.f. magnetic field
Figure 28 – Equivalent circuits of short-circuited microstrip line Test specimens and test fixtures
The structure of the all-shielded short-circuited microstrip line as test fixture is shown
schematically in Figure 29. A disk shape or square slab specimen is set at the end of the
short-circuited portion. To avoid disturbance from outside, the shielded covers are set up on
the upper side and both sides of the test fixture. The impedance of the test fixture except the
short end should be made at 50 Ω ± 2 Ω by adjusting the gap between the connector and the
strip line. The typical dimensions of the test fixture are shown in Table 1.

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SIST EN 60556:2007/A1:2017
IEC 60556:2006/AMD1:2016 – 5 –
© IEC 2016
Side shield cover a
(a) Top view
Side shield cover b
Microstrip line
Reference plane
Upper shield cover
2 (b) Side view
(thickness t)

NOTE The thickness of the strip line is 0,3 mm.
Figure 29 – Cross-sectional drawing of all-shielded
shorted microstrip line with specimen
Table 1 – Typical dimensions of test fixture
h w h gap w L L
1 1 2 2 1 2
2,0 7,0 3,7 20 8 5
0,35 ± 0,15
NOTE Dimensions in mm.

The shapes of specimens are a disk or a square slab. The typical dimensions of specimens
are shown in Table 2.
Table 2 – Specimen shape and typical dimensions
Disk Diameter D Quotient of diameter and thickness
D ≤ 5 mm φ up to 10 GHz t/D ≤ 1/20 (t = thickness)
Square slab Side length Quotient of side length and thickness
L ≤ 5 mm up to 10 GHz t/ L ≤ 1/20 (t = thickness)
2 2 Measuring apparatus
Figure 30 shows the block diagram of this measurement method. The test fixture with a
specimen is located between pole pieces of permanent magnets or an electro magnet to
generate gyromagnetic resonance. In case of a disk or square slab, in order to apply a static
magnetic field in normal to plane, the test fixture and pole piece should be capable of rotating
along two different axes which are orthogonal to each other. Under the constant static
magnetic field, the absolute value and phase of the S parameter of the test fixture are
measured by the sweeping frequency of the vector network analyzer (VNA).

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SIST EN 60556:2007/A1:2017
– 6 – IEC 60556:2006/AMD1:2016
 © IEC 2016
Magnet a
Test fixture with specimen
Magnet b

Figure 30 – Block diagram of measurement system Measuring procedure
The measuring procedure is as follows:
1) The VNA is calibrated on the cable end using an “open”, “short”, and “load” jig.
2) The total sweeping frequency points are selected so as to get more than 10 points within
the half linewidth ∆ f of the frequency defined below.
3) A specimen should be contacted and fixed on the corner of the short end and the ground.
4) To sustain the situation of µ = 1, a static magnetic field H larger than 3,2 × 10 A/m
should be applied in parallel to the x-direction of the r. f. magnetic field.
5) The absolute value and phase of S are measured as shown in Equation (64).
S = G exp(jδ ) (64)
11o o o
6) After removing H , the static magnetic field H is applied along the z-direction.
cal ext
7) The gyromagnetic resonance curve is observed in S .
8) The direction of H is adjusted to obtain the lowest resonant frequency, namely to be
normal to the plane of the specimens, by rotating the test fixture and pole pieces
9) The minimum value S is measured at the resonant frequency. This value should be
less than –1 dB.
10) Then the absolute value and phase of S are measured all over the frequency range as
shown in Equation (65).
S = G exp(jδ) (65)
11 Derivation of gyromagnetic resonance linewidth ∆H [21]
The derivation of gyromagnetic resonance linewidth is obtained as follows:
1) By dividing Equation (65) by Equation (64), E and F are defined as Equation (66).
S /S = G/ G exp{j(δ−δ )} = E + j F (66)
11 11o o o
2) Next, the calculations should be done.
C = y (E +1) + F X (67)
11 c

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SIST EN 60556:2007/A1:2017
IEC 60556:2006/AMD1:2016 – 7 –
© IEC 2016
C = X (E−1) − y F (68)
12 c
C = y { y (1−E) − F X } (69)
10 c
C = y { X (1+E) − F y} (70)
20 c
y is a characteristic admittance, usually y = 0,02 S.
X is defined by X = ω C −1/ωL (71)
c c o o
3) Also, the following calculations should be done.
C C − C C
10 11 20 12
A = (72)
2 2
C + C
11 12
C C + C C
10 12 20 11
B = (73)
2 2
C + C
11 12
4) The imaginary part ηµ”L of the complex inductance is calculated.
′′ (74)
ημ L =
o 2
ϖ{A + (B −ϖC ) }
5) The value of ηµ”L is directly proportional to µ”. With ηµ”L being on the vertical axis and
o o
the frequency being on the horizontal axis, the resonance curve can be drawn as shown in
Figure 31. In general, the curve is not always bilaterally symmetrical on the central
frequency axis. The resonant frequency f of the main peak and two half line widths of ∆f
r l
on the left and ∆f on the right could be derived. However, the smaller value of ∆f on the
h l
left side than of ∆f on the right side is adopted as a correct half width ∆ f because the
smaller one is considered to be less influenced by a higher magneto static mode. The
method to derive ∆f using the least square method is shown in
6) The relaxation constant α is derived by the Equation (75) [22].
α = ∆f / f (75)
7) The gyromagnetic resonance linewidth ∆H is derived through Equation (76) [23].
∆H = 4π∆ f /(µ γ ) (A/m) (76)
o eff
µ is the permeability of vacuum;
γ is the effective gyromagnetic ratio.

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SIST EN 60556:2007/A1:2017
– 8 – IEC 60556:2006/AMD1:2016
 © IEC 2016
α = 0,014 7

∆Η = 23,5 x 10 [T]
(n = 3)
2,1 2,2 2,3 2,4 2,5
Frequency (GHz)

Figure 31 –Observed absorption curve of imaginary part ηµ”L of inductance
for a 5 mm square garnet specimen with 0,232 mm thickness and Ms = 0,08 T
NOTE If the amplitude and phase of S are measured with an accuracy of ±0,02 dB and ±0,075° respectively, the
static magnetic field strength is measured with an accuracy of ±1 %, and L and C are determined with an
o o
accuracy ±10 %, the relative error of γ becomes equal to ±1 % and the relative error in the determination of ∆H
becomes equal to ±5 %, respectively. The derivation of half line width ∆f by the least square method
First, as an example, the measurement values ηµ”L of about 10 pieces on the lower
frequency side and of about 4 pieces on the higher frequency side including the maximum
value of (ηµ”L ) are gathered. Next, the inverse value of (ηµ”L ) is denoted as a(0) and
o max o max
the inverse values of ηµ”L (i) on both sides are denoted as a(−10), a(−9), … a(−1), a(1), a(2),
and a(3). The corresponding frequencies are f(0), f(−10), f(−9), … f(−1), f(1), f(2), and f(3)
respectively, where the lowest frequency is f(−10). Then the new frequency sets of
F(i) = f(i)−f(−10) are introduced. The value of a(i) obeys the parabolic relation as in Equation
(77) because ηµ”L (i) has Lorentzian characteristics.
y(i) = P F(i) + Q F (i) + R (77)
where P, Q, and R are the coefficients which should be determined by the least square method.
The error function of E is defined as follows:
2 2 2 2
E = Σ{y(i)−a(i)} = Σ{ P F(i) + Q F(i) + R −a(i)} (i = −10, −9,… 0, 1, 2, 3) (78)
The partial differentiations are performed regarding P, Q, and R to minimize E .
Eventually, the coefficients of P, Q, and R could be determined by the next equations.
P = D /D, Q = D /D, R = D /D (79)
4 3 2 2 3 2 4 2 2 4 3 2
D = X X X Dp = X A X X D = X X A X D = X X X A (80)
3 2 1 1 2 1 3 1 1 R 3 2 1
X X n A X n X A n X X A
2 1 1 2 2 1
Imaginary part of inductance ηµ”L (nH)

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SIST EN 60556:2007/A1:2017
IEC 60556:2006/AMD1:2016 – 9 –
© IEC 2016
4 3 2 0
X = Σ F(i) , X = Σ F(i) , X Σ F(i) , X = Σ F(i) , n = Σ F(i) (81)
4 3 2 = 1
X A = Σ F(i) a(i), X A = Σ F(i) a(i), A = Σ a(i) (82)
2 1
where n is the total number of the data. In this example n = 14.
As a result, the resonance frequency f is given by the Equation (83).
f = − Q /(2 P)+ f(−10) (83)
The half line width Δf is also given by the Equation (84).
4PR − Q
∆f =
P Calculation of effective gyromagnetic ratio γ
The value of γ could be derived through the next procedure.
1) By changing an applied magnetic field from H to H , the resonant frequency f and f
1 2 r1 r2
can be measured correspondingly.
2) The effective gyromagnetic ratio γ is derived by Equation (85).
2π( f − f )
r1 r2 −1 −1
γ = (T s ) (85)
μ (H1 − H 2)
the frequency difference (f − f ) should be larger than 600 MHz.
r1 r2 Calculations of fixture constant L and C
o o
The equivalent circuit seeing a specimen with µ = 1 from the reference plane is assumed to
be a parallel circuit with L and C as shown in Figure 32.
o o
S ←
Reference plane Shorted end

Figure 32 – Assumed equivalent circuit of the test fixture
If the test fixture impedance is designed to be 50 Ω except the short end and the effect of the
loading sample with µ = 1 is negligible, the fixture constants of L and C are calculated as
o o
L = L L (H) (86)
o 2

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SIST EN 60556:2007/A1:2017
– 10 – IEC 60556:2006/AMD1:2016
 © IEC 2016
C = 0,38 C L (F) (87)
o 2
L is the length of the sample, and L = 166,9 nH/m and C = 66,67 pF/m [24] are the
inductance and the capacitance per unit length of the 50 Ω transmission line. The factor of
0,38 in Equation (87) was determined to minimize the lumped element model error in the
wide measurement frequency range up to 10 GHz.
Table 3 shows the calculated fixture constants for 5 mm long specimens.
Table 3 – The fixture constants for 5 mm long specimens
Length of specimen L C
o o
mm nH pF
5 0,834 0,127

12.3.3 Transmission method Theory
A method recommended for the evaluation of ΔH and γ at an arbitrary frequency is based
on the measurement of the off-diagonal element of relative tensor permeability, κ, through a
signal transmission [25]. A test fixture model used in this measurement is shown in Figure 33.
The test fixture is constructed by two tri-plate lines stacked at right angle and a common
ground plane between them with a coupling hole at the cross point of the two lines. One line
used to apply an r.f. magnetic field to a specimen is terminated by a matched load to generate
a uniform r. f. magnetic field. The other line used to detect a signal from the specimen is
grounded at the edge of the coupling hole to avoid an error caused by leakage of an electric
field from the coupling hole. A grid parallel to the driving r. f. magnetic field is provided in the
coupling hole for further suppression of the electric field leakage.
Ferrite Coupling hole
Upper ground plane
Common ground plane
Detecting line
Driving line
Lower ground plane
Electric field leakage suppressing grid

(A part of the ground plane is cut away to show the bottom part of the test fixture.)
Figure 33 – Structure of test fixture to measure resonance linewidth by transmission
A ferrite specimen is positioned on the electric field leakage suppressor grid, facing the
detecting line. A magneto-static field orthogonal to the driving r. f. magnetic field is applied to
generate a precession of the electron spin in the ferrite and a gyromagnetic resonance. The
spin precession induces a signal in the detecting line. These relationships are shown in
Figure 34.

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SIST EN 60556:2007/A1:2017
IEC 60556:2006/AMD1:2016 – 11 –
© IEC 2016
Magneto-static field
Spin precession
Induced magnetic flux (m )
r.f. magnetic field (h )
Induced signal (b)
Driving line
Electron spin
Detecting line

Driving power (a)
(A part of the ground plane is cut away to show the bottom part of test the fixture.)
Figure 34 – Model to measure resonance linewidth by transmission
Through the precession of the electron spin, the application of the magneto-static field to the
test fixture results in a coupling between the driving and the detecting lines as shown in
Equation (88) [25].
C = C + 20log(κ ) (88)
C is the coupling coefficient in dB defined by the diameter wavelength ratio of the hole;
κ is the off-diagonal element of relative tensor permeability of the ferrite specimen in the
coupling hole.
Equation (88) shows that the signal intensity obtained from the test fixture is proportional to
the absolute value of the off-diagonal element in the relative tensor permeability, κ , of the
magnetized ferrite. The resonance is defined by the magneto-static field strength and the
frequency to maximize the transmitted power, and the relationship between the resonance
frequency and the internal magnetic field of the specimen is written as shown in Equation (89).
γ H
eff i
f =

f is the resonance frequency;
γ is the effective gyromagnetic ratio;
H is the internal magnetic field of the specimen.
The linewidth in the frequency, ∆f, is defined as the difference between the two frequencies f
and f at which the transmitted power by the ferrite material is one-half the maximum
transmission as shown below.
∆f = f − f
1 2
The line broadening by the external load is included in the linewidth. The broadening is
adjusted from the maximum value of the transmission as described in The linewidth

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SIST EN 60556:2007/A1:2017
– 12 – IEC 60556:2006/AMD1:2016
 © IEC 2016
described in the frequency is converted to the conventional linewidth in the magnetic field
strength by using the gyromagnetic ratio, γ . γ is a constant to define the resonance
eff eff
frequency from the internal magnetic field as shown in Equations (26) and (27) in Clause 6.
Considering that γ is independent from the shape of the specimen, it is calculated by two
resonance conditions as shown in Equation (91).
2π( f − f )
r1 r2
γ =
H − H
r1 r2
and f are the first and the second resonance frequencies, respectively;
r1 r2
H and H are the magnetic field strengths corresponding to the resonance, respectively.
r1 r2
The obtained linewidth in the frequency, ∆f, is converted to the conventional linewidth in the
magnetic field strength, ∆H, using γ . The details of the conversion are shown in as
well. Test specimens and test fixtures
The test specimens for this method may be either spherical or disc-shaped. The specimen
dimension shall be small compared with the wavelength in the specimen. The spherical
specimen resonates at a lower magnetic field than the disc-shaped specimen. However, the
linewidth broadening due to the insufficient saturation magnetization of the specimen and spin
wave loss as referred to in Clause 6 will be observed in the spherical specimen. For disc
specimens, the quotient of the diameter and the thickness shall exceed 15. Although the
magnetic field should be increased, the ambiguities of the linewidth appearing in the spherical
specimen become less so in the disc-shaped specimen shaped as described above. For
specimens with a relatively narrow linewidth, the measurement result depends strongly on the
surface state of the specimen. It is recommended to finish the surface of the specimen by
referring to 6.4.
By way of an example, Figure 35 illustrates the whole structure of a test fixture to evaluate the
resonance linewidth for 1 GHz to 10 GHz by transmission.
Detecting port Specimen
Specimen mount
Detecting conductor
Driving conductor
Driving port
Clamping screw
Driving chamber
Detecting chamber
Common ground plane

Figure 35 – Test fixture for measurement of resonance linewidth by transmission
The test fixture is constructed with a driving chamber, a detecting chamber, a ground plane
with a coupling hole and a mount to maintain the transmission between them at a minimum
when the magnetic field is not applied. The transmission with no magnetic field is called the
isolation of the test fixture. A specimen is glued on a sample mount put in the detecting line to
be positioned at the centre of the coupling hole.

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SIST EN 60556:2007/A1:2017
IEC 60556:2006/AMD1:2016 – 13 –
© IEC 2016
The characteristic impedance of the test fixture should be the same as the impedance of the
network analyzer, 50 Ω. It is favourable to adjust to 50 Ω ± 2,5 Ω for the transmission line of
the test fixture. The characteristic impedance of a transition from a connector to a
transmission line should favourably be adjusted to 50 Ω ± 5 Ω. The error c

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