U.S. patent application number 09/818268 was filed with the patent office on 2001-11-29 for dielectric porcelain composition, and dielectric resonator and nonradiative dielectric strip using same.
Invention is credited to Okamura, Takeshi.
Application Number | 20010046935 09/818268 |
Document ID | / |
Family ID | 18604094 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010046935 |
Kind Code |
A1 |
Okamura, Takeshi |
November 29, 2001 |
Dielectric porcelain composition, and dielectric resonator and
nonradiative dielectric strip using same
Abstract
An object of the invention is to provide a dielectric porcelain
composition with low rate of phase change of a cordierite phase as
a primary crystal phase, in which as a result of the low rate of
phase change the dielectric constant is from 4.5 to 6 and Q value
is 1,000 or more at 60 GHz, and to provide a dielectric resonator
and nonradiative dielectric strip using the same. The dielectric
porcelain composition comprises, as a principal component, a
complex oxide having a molar composition
xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein 10.ltoreq.x.ltoreq.40,
10.ltoreq.y.ltoreq.40, 20.ltoreq.z.ltoreq.80 , and x+y+z=100), and
a ratio of a (241) peak intensity .beta.p(241) and a (222) peak
intensity .beta.p(222) of X-ray diffraction of a .beta. phase of a
2MgO.2Al.sub.2O.sub.3.5SiO.sub.2 phase, which is a primary
crystalline phase of the complex oxide, is
0.8.ltoreq..beta.p(241)/.beta.- p(222).ltoreq.1.3.
Inventors: |
Okamura, Takeshi;
(Soraku-gun, JP) |
Correspondence
Address: |
HOGAN & HARTSON L.L.P.
500 S. GRAND AVENUE
SUITE 1900
LOS ANGELES
CA
90071-2611
US
|
Family ID: |
18604094 |
Appl. No.: |
09/818268 |
Filed: |
March 26, 2001 |
Current U.S.
Class: |
501/152 ;
501/153 |
Current CPC
Class: |
C04B 35/50 20130101;
C04B 35/10 20130101; H01P 3/165 20130101; H01P 7/10 20130101; C04B
35/18 20130101; C04B 35/20 20130101; H05K 1/0306 20130101 |
Class at
Publication: |
501/152 ;
501/153 |
International
Class: |
C04B 035/10; C04B
035/18; C04B 035/50 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2000 |
JP |
P2000-88183 |
Claims
What is claimed is:
1. A dielectric porcelain composition comprising: as a principal
component, a complex oxide having a molar composition
xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein 10.ltoreq.x.ltoreq.40,
10.ltoreq.y.ltoreq.40, 20.ltoreq.z.ltoreq.80, and x+y+z=100), a
primary crystalline phase of the complex oxide being a
2MgO.2Al.sub.2O.sub.3.5SiO- .sub.2 phase, and a ratio of a (241)
peak intensity .beta.p(241) and a (222) peak intensity .beta.p(222)
of X-ray diffraction of a .beta. phase of the primary crystalline
phase being 0.8.ltoreq..beta.p(241)/.beta.p(22- 2).ltoreq.1.3.
2. The dielectric porcelain composition of claim 1, containing 0.1
part by weight or less of an alkali metal element in terms of an
oxide per 100 parts by weight of the complex oxide.
3. The dielectric porcelain composition of claim 2, wherein the
alkali metal element is potassium.
4. The dielectric porcelain composition of claim 1, containing 0.1
to 15 parts by weight of a rare earth element in terms of an oxide
per 100 parts by weight of the complex oxide.
5. The dielectric porcelain composition of claim 4, wherein the
rare earth element is at least one selected from the group
consisting of Tb, Dy, Ho, Er, Yb and Lu.
6. A dielectric resonator comprising: a dielectric board; a
dielectric supporting member; and a dielectric porcelain for
resonance having a higher dielectric constant than that of the
supporting member, the dielectric porcelain provided on the
dielectric board via the dielectric supporting member, the
dielectric board and/or the dielectric supporting member comprising
a dielectric porcelain composition which comprises, as a principal
component, a complex oxide having a molar composition
xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein 10.ltoreq.x.ltoreq.40,
10.ltoreq.y.ltoreq.40, 20.ltoreq.z.ltoreq.80, and x+y+z=100), a
primary crystalline phase of the complex oxide being a
2MgO.2Al.sub.2O.sub.3.5SiO- .sub.2 phase, and a ratio of a (241)
peak intensity .beta.p(241) and a (222) peak intensity .beta.p(222)
of X-ray diffraction of a .beta. phase of the primary crystalline
phase being 0.8.ltoreq..beta.p(241)/.beta.p(22- 2).ltoreq.1.3.
7. The dielectric resonator of claim 6, wherein the dielectric
porcelain composition contains 0.1 part by weight or less of an
alkali metal element in terms of an oxide per 100 parts by weight
of the complex oxide.
8. The dielectric resonator of claim 7, wherein the alkali metal
element is potassium.
9. The dielectric resonator of claim 6, wherein the dielectric
porcelain composition contains 0.1 to 15 parts by weight of a rare
earth element in terms of an oxide per 100 parts by weight of the
complex oxide.
10. The dielectric resonator of claim 9, wherein the rare earth
element is at least one selected from the group consisting of Tb,
Dy, Ho, Er, Yb and Lu.
11. A nonradiative dielectric strip comprising: a pair of parallel
flat conductive bodies arranged with a distance of 1/2 or less of a
wavelength of a high frequency signal; and a dielectric strip
disposed between the parallel flat conductive bodies, for
transmitting the high frequency signal, the dielectric strip
comprising a dielectric porcelain composition which comprises, as a
principal component, a complex oxide having a molar composition
xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein 10.ltoreq.x.ltoreq.40,
10.ltoreq.y.ltoreq.40, 20.ltoreq.z.ltoreq.80, and x+y+z=100), a
primary crystalline phase of the complex oxide being a
2MgO.2Al.sub.2O.sub.3.5SiO.sub.2 phase, and a ratio of a (241) peak
intensity .beta.p(241) and a (222) peak intensity .beta.p(222) of
X-ray diffraction of a .beta. phase of the primary crystalline
phase being 0.8.ltoreq..beta.p(241)/.beta.p(222).ltoreq.1.3.
12. The nonradiative dielectric strip of claim 11, where the
dielectric porcelain composition contains 0.1 part by weight or
less of an alkali metal element in terms of an oxide per 100 parts
by weight of the complex oxide.
13. The nonradiative dielectric strip of claim 2, wherein the
alkali metal element is potassium.
14. The nonradiative dielectric strip of claim 11, wherein the
dielectric porcelain composition contains 0.1 to 15 parts by weight
of a rare earth element in terms of an oxide per 100 parts by
weight of the complex oxide.
15. The nonradiative dielectric strip of claim 14, wherein the rare
earth element is at least one selected from the group consisting of
Tb, Dy, Ho, Er, Yb and Lu.
16. The nonradiative dielectric strip of claim 11, wherein a
dielectric constant of the dielectric porcelain composition is from
4.5 to 6.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a dielectric porcelain
composition for high frequency waves, used in a high frequency band
of e. g., microwaves or millimeter waves, particularly, to a
dielectric porcelain composition useful as a material for circuit
boards of microwave integrated circuits, millimeter waves
integrated circuits and the like, dielectric strips and dielectric
antennas used in a microwave band and a millimeter wave band, and
to a dielectric resonator and nonradiative dielectric strip using
the same.
[0003] 2. Description of the Related Art
[0004] There have been cases in high frequency circuits such as
microwave integrated circuits and millimeter wave integrated
circuits that such a structure is employed that a dielectric
porcelain for resonance is fixed on a dielectric board through a
dielectric supporting member.
[0005] FIG. 1 is a cross sectional view showing a constitutional
example of a dielectric resonator. That is an example of a
dielectric resonator applied to a dielectric resonator control type
microwave oscillator, constituted such that a dielectric porcelain
1 is attached to a dielectric board 3 through a dielectric
supporting member 2 and is electromagnetically coupled to a strip
line 4 formed on the dielectric board 3 by utilizing an
electromagnetic field H which leaks outside the dielectric
porcelain 1, which are housed in a metallic container 5.
[0006] Since a resonance system of high unloaded Q level can be
constituted in the high frequency circuit by controlling the
leakage of electric field of the dielectric porcelain 1 through the
dielectric supporting member 2, it is necessary to use, for the
dielectric supporting member 2, a material having a low dielectric
constant and a small dielectric loss (tan.delta.), i.e., a large Q
value. Therefore, forsterite (2MgO.SiO.sub.2) ceramics having a
dielectric constant of about 7 and a Q value at a measuring
frequency of 10 GHz of about 15,000 has been used as the material
for the dielectric supporting member 2, and alumina ceramics having
a dielectric constant of about 10 and a Q value at a measuring
frequency of 10 GHz of about 20,000 or more has been mainly used as
the material for the dielectric board 3.
[0007] Cordierite (2MgO.2Al.sub.2O.sub.3.5SiO.sub.2) ceramics has
been known as a dielectric material having a low dielectric
constant. Since a dense sintered body of the cordierite ceramics is
difficult to obtain owing to its remarkably narrow sintering
temperature range, glass ceramics has been known that is obtained
by adding a glass material to result a dielectric constant of from
4 to 6 and a Q value at a measuring frequency of 10 GHz of about
1,000.
[0008] Furthermore, there has been known a nonradiative dielectric
guide (hereinafter referred to as an NRD guide) having a guide for
transmitting a high frequency signal comprising a dielectric
material.
[0009] FIG. 2 is a partially cutaway perspective view showing a
basic constitution of an NRD guide of the invention and the
conventional art. An NRD guide S1 comprises a dielectric strip 12
intervening between a pair of parallel flat conductive bodies 11
and 13 having a distance of .lambda./2 or less, in which .lambda.
is the wavelength of a high frequency signal (electromagnetic
wave), such as a millimeter wave, propagating in the dielectric
strip 12. In the NRD guide S1, the electromagnetic wave is shielded
and cannot enter from the outside when the distance of the parallel
flat conductive bodies 11 and 13 is 1/2 or less of the wavelength
.lambda. of the high frequency signal, but when the dielectric
strip 12 is made intervene between the parallel flat conductive
bodies 11 and 13, the electromagnetic wave can propagate along the
dielectric strip 12 inside the same, and a radiation wave is
suppressed by the shielding effect of the parallel flat conductive
bodies 11 and 13. In FIG. 2, a part of the upper parallel flat
conductive body 13 is cut for viewing the interior. The wavelength
.lambda. of the high frequency signal is that at the use frequency
in the air.
[0010] The electromagnetic wave propagation mode of the NRD guide
S1 includes two modes, i.e., the LSM (longitudinal section
magnetic) mode and the LSE (longitudinal section electric) mode,
and the LSM mode that exhibits a small loss is generally
employed.
[0011] A curved dielectric strip 12 can also be used, and in this
case, since an electromagnetic wave can easily be propagated in a
curvilinear form, an advantage can be obtained in that a millimeter
wave integrated circuit can be downsized, and high flexibility in
circuit design can be obtained.
[0012] As the material of the dielectric strip 12 of the NRD guide
S1, a resin material having a dielectric constant of from 2 to 4,
such as Teflon and polystyrene, has been conventionally used owing
to its easiness in processing.
[0013] However, the dielectric constants of alumina ceramics and
forsterite ceramics used in the conventional resonator are about 10
and about 7, respectively, and therefore, a material having a lower
dielectric constant is being demanded associated with spreading of
a dielectric resonator for a high frequency band in recent
years.
[0014] On the other hand, porcelain, such as glass ceramics, which
is generally used as a low dielectric constant material, has a
small dielectric constant of about from 4 to 6 but has a Q value of
about 1,000 at 10 GHz, and therefore, a low dielectric constant
material having a higher Q value is being demanded associated with
spreading of a dielectric resonator for a high frequency band in
recent years.
[0015] Furthermore, since alumina ceramics, which is mainly used as
the dielectric board 3 of the dielectric resonator, has a
relatively high dielectric constant of about 10, it involves such a
problem that when a strip line of a high impedance is to be formed,
the line width is too decreased to about 1 .mu.m or less to cause
breakage, and fluctuation in the relative line width is increased,
whereby the defective fraction is increased when a microwave
integrated circuit is fabricated by using the dielectric
resonator.
[0016] This is because the impedance of the strip line in the
dielectric board 3 is inversely proportional to the dielectric
constant thereof and the width of the strip line, respectively,
assuming that the thickness of the dielectric board 3 is constant.
Therefore, the impedance can be increased by using a material
having a lower dielectric constant instead of reduction in the
width of the strip line. Thus, a material having a low dielectric
constant is being demanded.
[0017] In order to solve the problems, the inventors have proposed
a dielectric porcelain composition for a high frequency and a
dielectric resonator, which comprise a complex oxide containing Mg,
Al and Si as metallic elements, in which the molar composition of
the respective metallic elements in the oxide
xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 satisfies 10.ltoreq.x.ltoreq.40,
10.ltoreq.y.ltoreq.40, 20.ltoreq.z.ltoreq.80, and x+y+z=100, the
dielectric constant is 6 or less, and the Q value of 2,000 or more
at a measuring frequency of 10 GHz (Japanese Unexamined Patent
Publication JP-A 9-48661 (1997)).
[0018] The dielectric porcelain composition for high frequencies is
of excellent properties as having a dielectric constant lower than
those of alumina ceramics and forsterite ceramics, and a Q value
higher than that of glass ceramics. However, a dielectric porcelain
composition exhibiting a high Q value at a higher frequency is
still demanded.
[0019] When the conventional NRD guide is constituted by a
dielectric strip using a dielectric material comprising a resin
material, such as Teflon and polystyrene, there is a problem that
the curvature loss at a curved part of the dielectric strip and the
loss at a junction of the dielectric strips are large. Therefore, a
sharp curved part cannot be formed in the dielectric strip, which
brings about, as a result, such a problem that the NRD guide has a
large size. In the case where a loose curved part is formed in the
dielectric strip, it is necessary that the curvature of the curved
part be precisely determined to suppress the high frequency signal
loss.
[0020] Furthermore, the frequency range that can be used under the
condition that the curvature loss is small is 1 to 2 GHz in the
vicinity of 60 GHz, which is insufficient. This is because in the
case where the NRD guide is constituted with a dielectric material
having a dielectric constant of from 2 to 4, the distance between
the LSM mode and the LSE mode is too close as about 3 GHz, and thus
a part of the electromagnetic wave in the LSM mode is converted to
the LSE mode. That is, with respect to the diffusion
characteristics of the LSM mode and the LSE mode, the diffusion
curves of the two modes is separated from each other by only about
3 GHz at B/B0=0 (B represents a propagation constant of a high
frequency signal in a dielectric strip, and B0 represents a
propagation constant of a high frequency signal in vacuum), which
causes the conversion of a part of the electromagnetic wave in the
LSM mode to the LSE mode. There has been a product using ceramics
having a dielectric constant of about 10, such as alumina, as the
material of the dielectric strip, but in order to use it at a high
frequency of 50 GHz of higher, it is necessary that the width of
the dielectric strip is extremely narrow, and it is not practical
on processability and workability of fabrication, i.e., on
productivity.
[0021] Furthermore, the cross section of the dielectric strip
becomes smaller when the frequency becomes higher. For example, in
the case where a dielectric strip having a cross sectional size of
about 1 mm.times.2 mm and a length of about 10 mm is formed with
porcelain and arranged, a problem occurs in that the dielectric
strip is extremely liable to broken on handling upon production.
Moreover, it is necessary to retain the dielectric strip by a pair
of parallel flat conductive bodies, but a problem occurs in that
the dielectric strip is broken upon fastening with the parallel
flat conductive bodies.
SUMMARY OF THE INVENTION
[0022] An object of the invention is to provide a dielectric
porcelain composition in which phase conversion of .alpha. phase to
.beta. phase of a cordierite phase as a primary crystalline phase
is not large, i.e., the phase conversion to .beta. phase does not
sufficiently proceed, so as to have a dielectric constant of from
4.5 to 6 and a Q value of 1,000 or more at 60 GHz. Another object
of the invention is to increase impedance in a dielectric resonator
by using a dielectric board material of low dielectric constant
comprising the dielectric porcelain composition, instead of by
reducing the width of a strip line on a dielectric board. Still
another object of the invention is to provide an NRD guide using a
dielectric strip with small conversion from LSM mode to LSE mode of
electromagnetic waves, comprising the dielectric porcelain
composition and having a curved part, so as to broaden the usable
frequency range even when the sharp curved part is used, whereby a
millimeter wave integrated circuit can be downsized with high
workability and high freedom on design.
[0023] The invention provides a dielectric porcelain composition
comprising, as a principal component, a complex oxide having a
molar composition xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein
10.ltoreq.x.ltoreq.40, 10.ltoreq.y.ltoreq.40,
20.ltoreq.z.ltoreq.80, and x+y+z=100), a primary crystalline phase
of the complex oxide being a 2MgO.2Al.sub.2O.sub.3.5SiO.sub.2
phase, and a ratio of a (241) peak intensity .beta.p(241) and a
(222) peak intensity .beta.p(222) of X-ray diffraction of a .beta.
phase of the primary crystalline phase being
0.8.ltoreq..beta.p(241)/.beta.p(222).ltoreq.1.3.
[0024] According to the invention, the principal component of the
dielectric porcelain composition is the complex oxide having a
molar composition of the specific range, and the primary
crystalline phase thereof is the cordierite
(2MgO.2Al.sub.2O.sub.3.5SiO.sub.2) phase of the specific phase
conversion state, whereby such characteristics can be obtained that
the dielectric constant is from 4.5 to 6.0, and the Q value is
1,000 or more at 60 GHz.
[0025] In the invention it is possible that the dielectric
porcelain composition contains 0.1 part by weight or less of an
alkali metal element in terms of an oxide per 100 parts by weight
of the complex oxide.
[0026] According to the invention, the rate of phase conversion of
the .alpha. phase to the .beta. phase of the cordierite
(2MgO.2Al.sub.2O.sub.3.5SiO.sub.2) phase as the primary crystalline
phase is made slow by decreasing the content of an alkali metal
element, so as to put the cordierite phase to the .beta. phase
which is in a state closer to the .alpha. phase, whereby a
dielectric porcelain composition exhibiting high Q value can be
stably obtained.
[0027] In the invention it is preferable that the alkali metal
element is potassium.
[0028] According to the invention, by making small the content of
potassium, which particularly makes faster the rate of phase
conversion of the .alpha. phase to the .beta. phase of the
cordierite (2MgO.2Al.sub.2O.sub.3.5SiO.sub.2) phase, the cordierite
phase can be easily put to the .beta. phase which is in a state
closer to the .alpha. phase, whereby a dielectric porcelain
composition exhibiting high Q value can be stably obtained.
[0029] In the invention it is preferable that the dielectric
porcelain composition contains 0.1 to 15 parts by weight of a rare
earth element in terms of an oxide per 100 parts by weight of the
complex oxide.
[0030] According to the invention, since the dielectric porcelain
composition contains a certain amount of a rare earth element, the
sintering conditions of the dielectric porcelain composition can be
improved without largely deteriorating the characteristics such as
Q value. That is, in order to obtain such characteristics that the
dielectric constant is from 4.5 to 6.0, and the Q value is 1,000 or
more at a measuring frequency of 60 GHz, the sintering temperature
range can be broadened to about 100.degree. C., which has been
conventionally controlled with a width of about 10.degree. C.,
whereby the production thereof becomes easy to remarkably improve
the mass productivity.
[0031] In the invention it is preferable that the rare earth
element is at least one selected from the group consisting of Tb,
Dy, Ho, Er, Yb and Lu.
[0032] According to the invention, sintering can be conducted at a
low temperature particularly without deterioration of Q value,
whereby the production of the dielectric porcelain composition
becomes easy to remarkably improve the mass productivity.
[0033] The invention provides a dielectric resonator
comprising:
[0034] a dielectric board;
[0035] a dielectric supporting member; and
[0036] a dielectric porcelain for resonance having a higher
dielectric constant than that of the supporting member, the
dielectric porcelain provided on the dielectric board via the
dielectric supporting member,
[0037] the dielectric board and/or the dielectric supporting member
comprising a dielectric porcelain composition which comprises, as a
principal component, a complex oxide having a molar composition
xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein 10.ltoreq.x.ltoreq.40,
10.ltoreq.y.ltoreq.40, 20.ltoreq.z.ltoreq.80, and x+y+z=100), a
primary crystalline phase of the complex oxide being a
2MgO.2Al.sub.2O.sub.3.5SiO- .sub.2 phase, and a ratio of a (241)
peak intensity .beta.p(241) and a (222) peak intensity .beta.p(222)
of X-ray diffraction of a .beta. phase of the primary crystalline
phase being 0.8.ltoreq..beta.p(241)/.beta.p(22- 2).ltoreq.1.3.
[0038] According to the invention, since the dielectric supporting
member is of low dielectric constant and of large Q value, leakage
of the electric field of the dielectric porcelain through the
dielectric supporting member can be controlled, whereby a resonance
system of high unloaded Q can be constituted. Furthermore, since
the dielectric board is of low dielectric constant, the impedance
can be increased without reduction in the line width of the strip
line. According to the constitution, a high frequency circuit such
as a microwave integrated circuit, can be produced with high
reliability.
[0039] In the invention it is preferable that the dielectric
porcelain composition contains 0.1 part by weight or less of an
alkali metal element in terms of an oxide per 100 parts by weight
of the complex oxide.
[0040] According to the invention, the dielectric board and/or the
dielectric supporting member exhibiting high Q value can be stably
obtained by decreasing the content of an alkali metal element in
the dielectric porcelain composition, whereby a high frequency
circuit such as a microwave integrated circuit can be produced with
high reliability.
[0041] In the invention it is preferable that the alkali metal
element is potassium.
[0042] According to the invention, the dielectric porcelain
composition exhibiting high Q value can be stably obtained by
decreasing the content of potassium in the dielectric porcelain
composition, whereby a high frequency circuit such as a microwave
integrated circuit can be produced with high reliability.
[0043] In the invention it is preferable that the dielectric
porcelain composition contains 0.1 to 15 parts by weight of a rare
earth element in terms of an oxide per 100 parts by weight of the
complex oxide.
[0044] According to the invention, the sintering conditions of the
dielectric porcelain composition can be improved without largely
deteriorating the characteristics thereof, such as the Q value, by
containing a certain amount of a rare earth element, whereby the
production thereof becomes easy to remarkably improve the mass
productivity.
[0045] In the invention it is preferable that the rare earth
element is at least one selected from the group consisting of Tb,
Dy, Ho, Er, Yb and Lu.
[0046] According to the invention, sintering can conducted at a low
temperature particularly without deterioration of the Q value, by
containing the certain rare earth element, whereby the production
of the dielectric porcelain composition becomes easy to remarkably
improve the mass productivity.
[0047] The invention also provides a nonradiative dielectric strip
comprising:
[0048] a pair of parallel flat conductive bodies arranged with a
distance of 1/2 or less of a wavelength of a high frequency signal;
and
[0049] a dielectric strip disposed between the parallel flat
conductive bodies, for transmitting the high frequency signal,
[0050] the dielectric strip comprising a dielectric porcelain
composition which comprises, as a principal component, a complex
oxide having a molar composition xMgO.yAl.sub.2O.sub.3.zSiO.sub.2
(wherein 10.ltoreq.x.ltoreq.40, 10.ltoreq.y.ltoreq.40,
20.ltoreq.z.ltoreq.80, and x+y+z=100), a primary crystalline phase
of the complex oxide being a 2MgO.2Al.sub.2O.sub.3.5SiO.sub.2
phase, and a ratio of a (241) peak intensity .beta.p(241) and a
(222) peak intensity .beta.p(222) of X-ray diffraction of a .beta.
phase of the primary crystalline phase being
0.8.ltoreq..beta.p(241)/.beta.p(222).ltoreq.1.3.
[0051] In the invention it is preferable that the dielectric
porcelain composition contains 0.1 part by weight or less of an
alkali metal element in terms of an oxide per 100 parts by weight
of the complex oxide.
[0052] In the invention it is preferable that the alkali metal
element is potassium.
[0053] In the invention it is preferable that the dielectric
porcelain composition contains 0.1 to 15 parts by weight of a rare
earth element in terms of an oxide per 100 parts by weight of the
complex oxide.
[0054] In the invention it is preferable that the rare earth
element is at least one selected from the group consisting of Tb,
Dy, Ho, Er, Yb and Lu.
[0055] In the invention it is preferable that a dielectric constant
of the dielectric porcelain composition is from 4.5 to 6.
[0056] According to the invention, the dielectric strip for
transmitting a high frequency signal comprising the dielectric
porcelain composition having the specified characteristics is
provided between the pair of parallel flat conductive bodies
arranged with a distance of 1/2 or less of a wavelength of a high
frequency signal, and thus the dielectric constant of the
dielectric strip becomes about from 4.5 to 6.0, which is higher
than the conventional resin material, such as Teflon, but lower
than alumina ceramics, whereby the loss caused by conversion of the
electromagnetic wave in the LSM mode to the LSE mode can be
decreased. When a dielectric porcelain having a Q value of 1,000 or
more at a using frequency of 60 GHz is used, the transmission loss
can be small, and the width of the dielectric strip is not
necessarily extremely narrow to easily form the dielectric strip,
whereby the dielectric strip can be produce at a low cost with high
accuracy. Furthermore, since the dielectric constant of the
dielectric strip is higher than the resin material, such as Teflon,
the influence of the resin material can be suppressed even when a
supporting jig and a circuit board of the dielectric strip are
formed with the resin material. Accordingly, an NRD guide of a
small size and a low cost with a high degree of freedom on
production can be constituted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] Other and further objects, features, and advantages of the
invention will be more explicit from the following detailed
description taken with reference to the drawings wherein:
[0058] FIG. 1 is a cross sectional view showing a constitutional
example of a dielectric resonator of the invention and the
conventional art; and
[0059] FIG. 2 is a partially cutaway perspective view showing a
basic constitutional example of an NRD guide of the invention and
the conventional art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0060] The dielectric porcelain composition for high frequency, the
dielectric resonator and the NRD guide according to the invention
will be sequentially described below.
[0061] The dielectric porcelain composition of the invention
comprises, as a principal component, a complex oxide having a molar
composition xMgO.yAl.sub.2O.sub.3.zSiO.sub.2 (wherein
10.ltoreq.x.ltoreq.40 , 10.ltoreq.y.ltoreq.40,
20.ltoreq.z.ltoreq.80, and x+y+z=100), in which the primary
crystalline phase of the complex oxide is a
2MgO.2Al.sub.2O.sub.3.5SiO.sub.2 phase, and the ratio of a (241)
peak intensity .beta.p(241) and a (222) peak intensity .beta.p(222)
of X-ray diffraction of the .beta. phase of the primary crystalline
phase is 0.8.ltoreq..beta.p(241)/.beta.p(222).ltoreq.1.3.
[0062] The numeral (241) referred to herein means the azimuth of a
(241) crystal plane defined by JCPDS-ICDD (Joint Committee on
Powder Diffraction Standards International Center for Diffraction
Data), and the azimuths of the other crystal planes are the
same.
[0063] The reasons of the limitation on the compositional ratio of
the principal component of the dielectric porcelain composition to
the specified ranges are as follows. The molar ratio x (mol %) of
MgO is from 10 to 40 because a good sintered body is difficult to
obtain, and the Q value is liable to be low when x<10, whereas
the dielectric constant exceeds 6.0 when x>40. It is preferred
that x is from 15 to 35, and in this case, the Q value is
remarkably improved to 2,000 or more at 60 GHz.
[0064] The molar ratio y (mol %) of Al.sub.2O.sub.3 is from 10 to
40 because a good sintered body is difficult to obtain, and the Q
value becomes low when y<10, whereas the dielectric constant
exceeds 6 when y>40. It is preferred that y is from 17 to 35,
and in this case, the Q value is remarkably improved to 2,000 or
more at 60 GHz.
[0065] The molar ratio z (mol %) of SiO.sub.2 is from 20 to 80
because the dielectric constant exceeds 6 when z<20, whereas a
good sintered body is difficult to obtain, and the Q value becomes
low when z>80. It is preferred that z is from 30 to 65, and in
this case, the Q value is remarkably improved to 2,000 or more at
60 GHz.
[0066] Therefore, in order to obtain a Q value of 2,000 or more at
a measuring frequency of 60 GHz, it is preferred that x is from 15
to 35, y is from 17 to 35, and z is from 30 to 65, and it is the
most preferred that the composition is the cordierite composition,
i.e., x=22.2, y=22.2 and z=55.6.
[0067] The molar percentages x, y and z of MgO, Al.sub.2O.sub.3 and
SiO.sub.2 in the complex oxide can be determined by an analysis
method, such as an EPMA (electron probe microanalysis) method and
an XRD (X-ray diffraction) method.
[0068] As described in the foregoing, the dielectric porcelain
composition exhibiting a Q value of 1,000 or more at a measuring
frequency of 60 GHz can be sufficiently adapted to a dielectric
resonator for a high frequency band in recent years. While the
better, the higher the Q value is, it is preferred that the Q value
is 1,500 or more at a measuring frequency of 60 GHz.
[0069] In the dielectric porcelain composition according to the
invention, the ratio of the (241) peak intensity .beta.p(241) and
the (222) peak intensity .beta.p(222) of X-ray diffraction of the
.beta. phase of the cordierite phase as the primary crystalline
phase is defined as
0.8.ltoreq..beta.p(241)/.beta.p(222).ltoreq.1.3. The reasons of the
limitation are that the dielectric loss becomes too large due to
excessive progress of phase change from the a phase to the .beta.
phase when .beta.p(241)/.beta.p(222)<0.8, and the state where
.beta.p(241)/.beta.p(222)=1.3 means the .alpha. phase, i.e., the
most preferred crystal state, but .beta.p(241)/.beta.p(222) does
not exceed 1.3.
[0070] The reasons described in the foregoing will be specifically
described below. It has been known that the crystal phase of
cordierite includes the .alpha. phase and the .beta. phase, which
reversibly cause phase change (phase conversion) by a heat
treatment. While the phase conversion is a slight change of the
crystal lattice, the state of the phase change can be specified by
measuring the change of the X-ray diffraction patterns caused by
the change of the symmetry of the crystal, i.e., the change of the
peak intensity of X-ray diffracted at various angles caused by the
state of the crystal.
[0071] The .alpha. phase, which is the most preferred from the
standpoint that the dielectric constant is small and the dielectric
loss is small, changes into the .beta. phase upon sintering to
produce the dielectric porcelain composition. The peak intensity
caused by an X-ray (wavelength: 1.5406 .ANG.) at the specific
crystal plane changes associated with the phase conversion from the
a phase to the .beta. phase. The peak of (211) of the .alpha. phase
changes into the three peaks of (151), (241) and (311) of the
.beta. phase associated with the phase conversion from the .alpha.
phase to the .beta. phase. That is, the one peak of (211) of the
.alpha. phase is decreased in height and is separated into the
three peaks associated with the change in the crystal structure of
the .beta. phase (change in ratio of the length in the x axis
direction to the length in the y axis direction of the
crystal).
[0072] With respect to the (202) peak of the .alpha. phase, the
peak has no relationship to the phase conversion, and the peak
intensity cause no change. However, since the unit lattice changes
into the .beta. phase associated with the phase change, it
corresponds to the (222) peak in the .beta. phase.
[0073] Consequently, the state of phase conversion of cordierite
can be specified by the ratio of the (222) peak intensity of the
.beta. phase that causes no change in peak intensity by the phase
change to the peak intensity of (151), (241) and (311) that cause
change in peak intensity by the phase change. Following to the
progress of the phase conversion, the (241) peak, which is of the
largest peak intensity among the peaks of (151), (241) and (311) of
the .beta. phase, becomes small, and the (151) peak and the (311)
peak are formed on the both sides thereof. Therefore, the state of
the phase conversion can be specified by the ratio in intensity of
the (222) peak to the (241) peak in the .beta. phase, i.e.,
.beta.p(241)/.beta.p(222).
[0074] In the complex oxide as the principal component of the
dielectric porcelain composition, which is a sintered body
(ceramics), cordierite (2MgO.2Al.sub.2O.sub.3.5SiO.sub.2) in the
foregoing phase state is the primary crystal phase, and the complex
oxide may contain other crystal phases or may contain only the
crystal phase of cordierite. There are cases that mullite
(3Al.sub.2O.sub.3.2SiO.sub.2), spinel (MgO.Al.sub.2O.sub.3),
protoenstatite (a kind of steatite having magnesium metasilicate
(MgO.SiO.sub.2) as a principal component), clinoenstatite (a kind
of steatite having magnesium metasilicate (MgO.SiO.sub.2) as a
principal component), forsterite (2MgO.SiO.sub.2), cristobalite (a
kind of silicate (SiO.sub.2)), tridymite (a kind of silicate
(SiO.sub.2)) and sapphirine (a kind of silicate of Mg and Al) are
deposited on sintering. The deposited phase is changed depending on
the compositional ratio of MgO, Al.sub.2O.sub.3 and SiO.sub.2.
[0075] The dielectric porcelain composition of the invention
comprises the complex oxide as the main component and further
contains an alkali metal element, such as Li, Na, K and Rb, and a
rare earth element, such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd,
Tb, Dy, Ho, Er, Tm, Yb and Lu.
[0076] In the dielectric porcelain composition of the invention,
the content of an alkali metal element is preferably 0.1 part by
weight or less in terms of an oxide per 100 parts by weight of the
complex oxide. When it exceeds 0.1 part by weight, the cordierite
phase as the primary crystal phase is liable to change from the
.alpha. phase to the .beta. phase to decrease the Q value. The
better, the smaller the content of an alkali metal element, and it
is more preferably 0.03 part by weight or less. While an alkali
metal element may not be mixed, the element or an oxide thereof is
mixed as an impurity of a pulverization bowl or raw material powder
or as an object of improving the sintering property.
[0077] The rate of phase change from the a phase to the .beta.
phase is increased to lower the Q value particularly by
incorporating potassium among the alkali metal elements, and it is
therefore preferred that the content of potassium is 0.1 part by
weight or less.
[0078] In the dielectric porcelain composition of the invention,
the content of a rare earth element is preferably from 0.1 to 15
parts by weight in terms of an oxide per 100 parts by weight of the
complex oxide as the principal component. When the content is less
than 0.1 part by weight, the range of the sintering temperature, in
which the characteristics of a dielectric constant of from 4.5 to 6
and a Q value of 1,000 or more at a measuring frequency of 60 GHz
are obtained, is not broadened, whereby the dielectric porcelain
composition having such characteristics is difficult to be obtained
to deteriorate mass productivity. When it exceeds 15 parts by
weight, the dielectric constant becomes large, and the Q value
becomes small.
[0079] Among the rare earth elements, Tb, Dy, Ho, Er, Yb and Lu are
preferred from the standpoint that low temperature sintering can be
conducted without decreasing the Q value, and Yb is the most
preferred.
[0080] The content of an oxide of an alkali metal element can be
specified by atomic absorption spectrophotometry, and the content
of an oxide of a rare earth element can be specified by the EPMA
method or the XRD method.
[0081] The dielectric porcelain composition of the invention can be
produced in the following manner. For example, MgCO.sub.3 powder,
Al.sub.2O.sub.3 powder, SiO.sub.2 powder and Yb.sub.2O.sub.3 powder
as raw material powder are weighed at a prescribed proportion and
mixed in a wet state, followed by drying. The resulting mixture is
calcined in the air at a temperature of from 1,100 to 1,300.degree.
C., followed by pulverization. Prescribed amounts of powder of an
oxide of an alkali metal and powder of an oxide of a rare earth
element are added to the resulting raw material powder depending on
necessity, and an appropriate amount of an organic resin binder is
added thereto, followed by forming into a shape of a guide. The
resulting molded article is sintered at a temperature of from 1,250
to 1,450.degree. C. in the air to obtain the dielectric porcelain
composition.
[0082] In the dielectric porcelain composition of the invention,
one having no progress of phase conversion to the .beta. phase can
be produced by controlling the sintering temperature and the
sintering time. That is, a product of
0.8.ltoreq..beta.p(241)/.beta.p(222).ltoreq.1.3 can be produced.
The preferred temperature range where sintering can be conducted is
from 1,250 to 1,450.degree. C. When the temperature is less than
1,250.degree. C., sintering is difficult to be conducted, whereas
when it exceeds 1,450.degree. C., the cordierite phase is liable to
be decomposed and melted. The sintering time where the phase
conversion is hard to proceed is preferably less than 2 hours, and
the phase conversion proceeds when it is 2 hours or more.
Therefore, the phase conversion to the .beta. phase can be
suppressed to the range of the invention by a sintering temperature
range of from 1,250 to 1,450.degree. C. and a sintering time of
less than 2 hours. The sintering time is more preferably 90 minutes
or less. In the case where the sintering temperature is from 1,400
to 1,450.degree. C. where the phase change of the .beta. phase of
the cordierite phase actively proceed, the sintering time is
preferably 1 hour or less. Sintering becomes difficult when the
sintering time is less than 5 minutes even in the case of a small
size part, such as a dielectric board and a dielectric supporting
member of a dielectric resonator or a dielectric strip of an NRD
guide, and therefore the sintering time is preferably 5 minutes or
more.
[0083] The respective elements of Mg, Al and Si contained in the
dielectric porcelain composition are not limited to the oxide raw
material powder used in the foregoing production process of the
dielectric porcelain composition, and any substance that can form
an oxide upon baking, for example, an inorganic compound, such as a
carbonate and an acetate, and an organic compound, such as an
organic metal, may be used as a raw material.
[0084] The dielectric porcelain composition of the invention
contains Mg, Al and Si as the principal component elements and also
contains an alkali metal element or a rare earth element depending
on necessity, and there are some cases where other elements, such
as Ca, Ba, Fe, Cr, P, Sr, Ni, Co, In, Ga, Zr, Ti, Nb, Ta, Mo, W,
Mn, Cu, Zn, B, Ge and Sm, are contained as an impurity of a
pulverization bowl or raw material powder or as an object of
improving the sintering property. In this case, a dielectric
porcelain composition having a low dielectric constant and a high Q
value can also be obtained as far as the principal component
elements constitute the complex oxide satisfying the specific
composition range, and the complex oxide is contained as the
principal component.
[0085] The dielectric porcelain composition of the invention can
provide a dielectric constant of from 4.5 to 6.0 and a Q value of
1,000 or more at 60 GHz, which are optimum for a high frequency
circuit. Furthermore, the sintering conditions can be improved
without greatly deteriorating the characteristics of the dielectric
porcelain composition, whereby the production thereof becomes easy
to remarkably improve the mass productivity. Moreover, a high
frequency circuit, such as a microwave integrated circuit, can be
produced with high reliability by using the dielectric porcelain
composition of the invention.
[0086] The dielectric porcelain composition of the invention can be
applied to various electronic parts requiring a low dielectric
constant and a high Q value, for example, to an electronic circuit
board, a dielectric porcelain of a dielectric resonator, a
dielectric strip, a dielectric waveguide and a dielectric
antenna.
[0087] A dielectric resonator using the dielectric porcelain
composition of the invention will be described below. As shown in
FIG. 1, the dielectric resonator is constituted in such a manner
that a dielectric porcelain 1 for resonance is attached on a
dielectric board 3 through a dielectric supporting member 2 and is
electromagnetically coupled to a strip line 4 formed on the
dielectric board 3 by utilizing an electromagnetic field H leaking
outside the dielectric porcelain 1, which are housed in a metallic
container 5. The dielectric supporting member 2 and/or the
dielectric board 3 are formed with the dielectric porcelain
composition. The dielectric porcelain 1 has a higher dielectric
constant than the dielectric supporting member 2 and is formed
with, for example, alumina ceramics having a dielectric constant of
about 10.
[0088] In the dielectric resonator of the invention, the dielectric
supporting member has a low dielectric constant and a large Q
value, and thus leakage of the electric field of the dielectric
porcelain through the dielectric supporting member can be
controlled, whereby a resonance system of high unloaded Q can be
constituted. Furthermore, the dielectric board has a low dielectric
constant, and thus the impedance can be increased without reduction
in the line width of the strip line. According to the constitution,
a high frequency circuit, such as a microwave integrated circuit,
can be produced with high reliability.
[0089] The NRD guide of the invention will be described below. As
shown in FIG. 2, the NRD guide has such a basic constitution that a
dielectric strip 12 comprising the dielectric porcelain composition
intervenes between a pair of parallel flat conductive bodies 11 and
13 arranged at a distance of .lambda./2 or less, in which .lambda.
is the wavelength of the high frequency signal. The dielectric
porcelain composition is used as the material of the dielectric
strip 12, and the dielectric porcelain composition has a dielectric
constant of from 4.5 to 6. When the dielectric constant is less
than 4.5, conversion of an electromagnetic wave in the LSM mode to
the LSE mode becomes large to increase the loss, whereas when the
dielectric constant exceeds 6, it is necessary that the width of
the dielectric strip 12 becomes extremely small upon using at a
frequency of 50 GHz or more, whereby such a problem occurs that
processing becomes difficult, and the strength is deteriorated. The
dielectric strip 12 exhibits such characteristics that the Q value
is 1,000 or more at a frequency of 60 GHz, which are sufficient
characteristics as a transmission guide used for a microwave band
and a millimeter wave band in recent years.
[0090] According to the characteristics of the dielectric strip 12
described in the foregoing, the NRD guide of the invention can be
applied to a high frequency circuit utilizing a high frequency
signal of a several tens to several hundreds GHz band, and is
particularly preferably applied to a high frequency band of 50 GHz
or higher, and especially 70 GHz or higher. Specifically, the NRD
guide of the invention can be used in a wireless LAN system and a
millimeter wave radar for automobiles. For example, a millimeter
wave is guided by the dielectric strip 12 to irradiate barriers
around an automobile and other automobiles, then the reflected wave
is received by another dielectric guide and combined with the
original high frequency signal in the other dielectric strip to
obtain an intermediate frequency signal, which is then analyzed to
obtain distances to the barriers and the other automobiles and
movement speeds thereof.
[0091] The parallel flat conductive bodies 11 and 13 may preferably
be formed with a conductor plate of, for example, Cu, Al, Fe, Ag,
Au, Pt or SUS (stainless steel), from the standpoint of high
electric conductivity and workability, and an insulating plate
having a layer of these conductors formed on the surface thereof
may also be used.
[0092] The dielectric strip can also be applied to various kinds of
electronic parts, electronic circuits and photoelectronic circuits
utilizing a dielectric strip for transmitting a high frequency
signal, as well as an NRD guide.
[0093] The nonradiative dielectric strip of the invention has a
dielectric constant of the dielectric strip of about from 4.5 to 6,
which is higher than the conventional resin material, such as
Teflon, but lower than alumina ceramics, whereby the loss caused by
conversion of the electromagnetic wave in the LSM mode to the LSE
mode can be decreased. When a dielectric porcelain having a Q value
of 1,000 or more at a using frequency of 60 GHz is used, the
transmission loss can be small, and the width of the dielectric
strip is not necessarily extremely narrow to easily form the
dielectric strip, whereby the dielectric strip can be produce at a
low cost with high accuracy. Furthermore, since the dielectric
constant of the dielectric strip is higher than that of the resin
material, such as Teflon, the influence of the resin material can
be suppressed even when a supporting jig and a circuit board of
dielectric strip are formed with the resin material and placed in
the vicinity of the dielectric guide. Accordingly, an NRD guide of
a small size and a low cost with a high degree of freedom on
production can be constituted.
[0094] The invention is not construed as being limited to the
foregoing embodiments, but various changes can be conducted without
deviation from the substance of the invention.
[0095] The invention will be further described with reference to
the following example.
EXAMPLES
[0096] A dielectric porcelain composition was produced by the
following steps (1) to (3).
[0097] (1) MgCO.sub.3 powder having a purity of 99.0% by weight,
Al.sub.2O.sub.3 powder having a purity of 99.7% by weight,
SiO.sub.2 powder having a purity of 99.4% by weight and
K.sub.2O.sub.3 powder having a purity of 99.0% by weight as raw
material powder were respectively weighed to make the compositions
of Nos. 1 to 35 shown in Table 1 below. The compositions of the
respective examples each was mixed in a wet state for 15 hours,
followed by drying. The mixtures each was calcined at 1,200.degree.
C. for 2 hours and then pulverized to obtain powder.
[0098] (2) An appropriate amount of an organic resin binder and the
amounts shown in Table 1 of an oxide of an alkali metal and an
oxide of a rare earth element were added to the resulting powder,
followed by granulation. The resulting granules were molded under a
pressure of 1,000 kg/cm.sup.2 to obtain cylindrical molded articles
each having a diameter of 8 mm and a thickness (height) of 5
mm.
[0099] (3) The molded articles were sintered in the air at the
temperatures shown in Table 1 for 90 minutes and then ground to be
a cylindrical shape having a diameter of 5 mm and a thickness of
2.25 mm, so as to obtain various kinds of samples of dielectric
porcelain composition having different compositions.
[0100] The samples were measured for the dielectric constant and
the Q value at a frequency of about 60 GHz by a dielectric cylinder
resonance method. The value of .beta.p(241)/.beta.p(222) was
measured by diffraction of an X-ray (wavelength: 1.5406 .ANG.). The
results obtained are shown in Table 1 below. The samples attached
with asterisks in Table 1 are samples outside the scope of the
invention.
1TABLE 1 Alkali metal Q oxide Additive value Sintering MgO
Al.sub.2O.sub.3 SiO.sub.2 (part by (part by Dielectric (60 .beta.p
(241)/ tempera- No. (mol %) (mol %) (mol %) weight) weight)
constant GHz) .beta.p (222) ture 1* 5 55 40 K.sub.2O -- 6.8 520 1.3
1,500 0.006 -- 2 10 10 80 K.sub.2O -- 4.8 1,400 1.1 1,400 0.02 -- 3
10 30 60 K.sub.2O -- 5.8 1,810 1.0 1,300 0.03 -- 4 10 40 50
K.sub.2O -- 5.8 1,850 1.3 1,420 0.006 -- 5 15 35 50 K.sub.2O -- 5.6
2,121 1.1 1,400 0.02 -- 6 17.5 17.5 65 K.sub.2O -- 4.8 2,040 1.0
1,350 0.03 -- 7 20 40 40 K.sub.2O -- 5.6 1,010 1.3 1,350 0.006 -- 8
22.2 22.2 55.6 K.sub.2O -- 4.8 2,880 1.3 1,440 0.006 -- 9 22.2 22.2
55.6 K.sub.2O -- 4.8 2,870 1.1 1,440 0.02 -- 10 22.2 22.2 55.6
K.sub.2O -- 4.8 2,810 1.0 1,440 0.03 -- 11 22.2 22.2 55.6 K.sub.2O
-- 4.8 1,500 0.9 1,440 0.05 -- 12 22.2 22.2 55.6 K.sub.2O -- 4.8
1,120 0.9 1,440 0.08 -- 13 22.2 22.2 55.6 K.sub.2O -- 4.8 1,060 0.8
1,440 0.1 -- 14* 22.2 22.2 55.6 K.sub.2O -- 4.9 630 0.7 1,440 0.15
-- 15* 22.2 22.2 55.6 K.sub.2O -- 4.9 490 0.7 1,440 0.3 -- 16 22.2
22.2 55.6 Na.sub.2O -- 4.8 2,300 1.0 1,440 0.03 -- 17* 22.2 22.2
55.6 Na.sub.2O -- 4.9 500 0.7 1,440 0.3 -- 18 25 17 58 K.sub.2O --
5.1 2,490 1.3 1,300 0.006 -- 19 25 27 48 K.sub.2O -- 5.6 2,770 1.1
1,300 0.02 -- 20 25.5 30 44.5 K.sub.2O -- 5.8 2,120 1.0 1,300 0.03
-- 21 30 10 60 K.sub.2O -- 5.2 1,500 1.3 1,300 0.006 -- 22 30 30 40
K.sub.2O -- 5.6 2,500 1.1 1,350 0.02 -- 23 35 20 45 K.sub.2O -- 6.0
2,060 1.0 1,300 0.03 -- 24 35 35 30 K.sub.2O -- 5.8 2,080 1.3 1,400
0.006 -- 25 40 10 50 K.sub.2O -- 5.8 1,980 1.1 1,300 0.02 -- 26 40
20 40 K.sub.2O -- 5.5 1,020 1.0 1,250 0.03 -- 27 40 40 20 K.sub.2O
-- 6.0 1,470 1.3 1,300 0.006 -- 28* 40 50 10 K.sub.2O -- 7.9 520
1.3 1,400 0.006 -- 29* 58 10 32 K.sub.2O -- 7.5 1,250 1.3 1,220
0.006 -- 30 22.2 22.2 55.6 K.sub.2O Yb.sub.2O.sub.3 4.8 2,910 1.3
1,430 0.006 0.1 31 22.2 22.2 55.6 K.sub.2O Yb.sub.2O.sub.3 4.8
2,670 1.3 1,400 0.006 1.0 32 22.2 22.2 55.6 K.sub.2O
Yb.sub.2O.sub.3 4.8 2,750 1.3 1,380 0.006 5.0 33 22.2 22.2 55.6
K.sub.2O Yb.sub.2O.sub.3 4.9 3,010 1.3 1,380 0.006 7.0 34 22.2 22.2
55.6 K.sub.2O Yb.sub.2O.sub.3 5.0 3,010 1.3 1,380 0.006 10.0 35
22.2 22.2 55.6 K.sub.2O Yb.sub.2O.sub.3 5.4 2,100 1.3 1,380 0.006
15.0 Note: Samples with asterisks (Nos. 1, 14, 15, 17, 28 and 29)
are outside the scope of the invention.
[0101] As shown in Table 1, the dielectric porcelain composition
according to the invention had a dielectric constant of from 4.5 to
6 and a high Q value of 1,000 or more at a measuring frequency of
60 GHz.
[0102] The invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof. The present embodiments are therefore to be considered in
all respects as illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than by the
foregoing description and all changes which come within the meaning
and the range of equivalency of the claims are therefore intended
to be embraced therein.
* * * * *