Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2003-01-06
2004-03-02
Martin, David (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S794000, C361S795000, C361S780000, C361S750000, C361S751000, C361S760000, C174S255000, C174S256000
Reexamination Certificate
active
06700789
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a high-frequency wiring board for connecting and mounting a high-frequency integrated circuit or a high-frequency circuit device such as an IC and an LSI used in a high-frequency region of a millimeter waveband of 30 GHz or more, and more specifically, relates to a high-frequency wiring board which has a through conductor for signal transmission with an improved high-frequency signal transmission characteristic.
2. Description of the Related Art
As a conventional high-frequency wiring board which transmits a high-frequency signal, there is one which is shown in a section view of
FIG. 7 and a
plan view of
FIG. 8
, for example.
In
FIGS. 7 and 8
, reference numeral
21
denotes a high-frequency wiring board, reference numerals
22
a
to
22
d
denote dielectric layers, a first line conductor
23
and a second line conductor
24
are disposed to main faces
29
a
,
29
b
of the high-frequency wiring board
21
, and one ends of the first and second line conductors
23
,
24
are electrically connected to each other by a through conductor
25
. Moreover, ground conductors
26
and same plane ground conductors
28
are disposed to main faces of the dielectric layers
22
a
to
22
d
, and the ground conductors
26
and the same plane ground conductors
28
are electrically connected by a plurality of ground through conductors
27
.
More specifically, the high-frequency wiring board
21
comprises a dielectric board
22
, the first line conductor
23
, the second line conductor
24
, the through conductor
25
, the ground conductors
26
, the ground through conductors
27
and the same plane ground conductors
28
. The dielectric board
22
is formed by laminating the dielectric layers
22
a
,
22
b
,
22
c
,
22
d
. The first line conductor
23
is disposed onto the main face
29
a
of the dielectric layer
22
a
, which is a top face of the high-frequency wiring board
21
, and the second line conductor
24
is disposed onto the main face
29
b
of the dielectric layer
22
d
, which is a bottom face of the high-frequency wiring board
21
. One end
23
a
of the first line conductor
23
and one end
24
a
of the second line conductor
24
overlap each other when viewed from a thickness direction of the dielectric layers
22
a
to
22
d
, and the one ends
23
a
,
24
a
are electrically connected to each other by the through conductor
25
piercing the dielectric layers
22
a
to
22
d
. On the respective main faces defining interlayer border planes of the dielectric layers
22
a
to
22
d
, ground conductors
26
formed so as to surround the through conductor
25
are disposed with specified spaces to the through conductor
25
. The same plane ground conductors
28
which are formed with a specified space from the first line conductor
23
on the main face
29
a
of the dielectric layer
22
a
with the first line conductor
23
formed and formed with a specified space from the second line conductor
24
on the main face
29
b
of the dielectric layer
22
d
with the second line conductor
24
formed are disposed. The ground conductors
26
and the same plane ground conductors
28
are electrically connected by the ground through conductors
27
.
This high-frequency wiring board has a problem that because a frequency of a high-frequency signal becomes higher in recent years, unnecessary radiation of a high-frequency signal occurs from between the ground through conductors
27
, with the result that radiation loss of a high-frequency signal increases and a transmission characteristic deteriorates.
Hence, as a technique of inhibiting unnecessary radiation of a high-frequency signal from between the ground through conductors
27
, such a technique that, by setting the number of the ground through conductors
27
formed so as to surround the through conductor
25
to five or more, enables decrease of radiation loss of a high-frequency signal and improvement of a high-frequency signal transmission characteristic is proposed, for example (refer to Japanese Unexamined Patent Publication JP-A 5-206678 (1993)).
However, the above conventional high-frequency wiring board has a problem that although unnecessary radiation of a high-frequency signal from between the ground through conductors is inhibited as a result of increasing the number of the ground through conductors, a wavelength is short in a high-frequency region of a millimeter waveband, and therefore, a mode (a high-order mode) different from a basic propagation mode occurs at a point of the through conductor in a case where the length of the through conductor is &lgr;/4 or more, with the result that a transmission characteristic deteriorates greatly as a frequency becomes higher.
SUMMARY OF THE INVENTION
The invention was made in view of the above problems, and an object of the invention is to provide a high-frequency wiring board which is capable of inhibiting a high-order mode occurring at a point of a through conductor and enables obtaining a good transmission characteristic in a high-frequency signal of a millimeter waveband of 30 GHz or more.
The invention provides a high-frequency wiring board comprising:
a dielectric board formed by laminating a plurality of dielectric layers;
a first line conductor formed on a main face of one dielectric layer of the dielectric board;
a second line conductor formed on a main face of another dielectric layer of the dielectric board;
a through conductor for electrically connecting one end of the first line conductor to one end of the second line conductor by piercing the dielectric layers between the first line conductor and the second line conductor;
same plane ground conductors which are formed with a specified space from the first line conductor on the main face of the dielectric layer on which main face the first line conductor is formed and are formed with a specified space from the second line conductor on the main face of the dielectric layer on which main face the second line conductor is formed;
ground conductors formed on the main faces of the dielectric layers between the first line conductor and the second line conductor so as to surround the through conductor; and
a plurality of ground through conductors which are formed on the dielectric layers so as to surround the through conductor and which electrically connect the same plane ground conductors and the ground conductors,
wherein L>&lgr;/4 and &pgr;(A+B)≦&lgr; are satisfied in which
L is a length of the through conductor, A is a diameter of the through conductor, B is shortest distances between the through conductor and the ground through conductors, &pgr; is a circle ratio and &lgr; is an effective wavelength of a high-frequency signal transmitted by the through conductor.
According to the invention, as described above, a diameter A and length L of the through conductor and shortest distances B between the through conductor and the ground through conductors are set within specified ranges with respect to an effective wavelength &lgr; of a high-frequency signal, so that even in the case of a long through conductor with a length of &lgr;/4 or more, distances between the through conductor and the ground through conductors are short enough with respect to an effective wavelength of a high-frequency signal, a standing wave and the like between the through conductor and the ground through conductors is hard to occur, it is possible to inhibit occurrence of a high-order mode at a point of the through conductor also in a high-frequency region of a millimeter waveband, and consequently, it is possible to realize a good transmission characteristic in a high-frequency signal of a millimeter waveband.
Further, in the invention it is preferable that in the above construction, a distance H between the ground conductor and the same plane ground conductor is equal to or less than &lgr;/2.
According to the invention, as a result that distances between the ground conductors and the same plane ground conductors, that is, connection lengths of the gr
Hogan & Hartson
Kyocera Corporation
Martin David
Tran Thanh Yen
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