Wave transmission lines and networks – Coupling networks – Frequency domain filters utilizing only lumped parameters
Reexamination Certificate
2003-01-10
2004-11-23
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Coupling networks
Frequency domain filters utilizing only lumped parameters
C333S175000, C333S204000
Reexamination Certificate
active
06822534
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laminated electronic component, a laminated duplexer and a communication device mainly mounted on a high frequency radio device such as a cellular phone.
BACKGROUND ART
With miniaturization of communication devices, laminated electronic components are being used as high frequency devices in recent years. With reference to the attached drawings, an example of the above-described conventional laminated electronic component will be explained below.
FIG. 3
shows an exploded perspective view of a conventional electronic part. As shown in
FIG. 3
, the laminated electronic component comprises dielectric layer
301
to dielectric layer
308
placed one atop another. A grounding electrode
309
is placed on the dielectric layer
301
and capacitor electrode
310
is placed on the dielectric layer
302
. Furthermore, strip lines
311
and
312
are placed on the dielectric layer
303
and connected at a connection point
313
.
A capacitor electrode
314
, a grounding electrode
315
, a capacitor electrode
316
and a grounding electrode
317
are placed on dielectric layers
304
,
305
,
306
and
307
, respectively. Furthermore, the capacitor electrode
310
is connected to a connection point
318
of the strip line
311
via a via hole
322
and the capacitor electrode
314
is connected to the connection point
313
via a via hole
323
. Furthermore, the capacitor electrode
316
is connected to a connection point
319
of the strip line
312
via a via hole
324
.
The grounding electrodes
315
and
317
are connected to the grounding electrode
309
via an external electrode
320
formed on one side of the laminated electronic component, and the external electrode terminals of the circuit form an input electrode and output electrode by extending one end of the strip lines
311
and
312
to the end face of the laminated electronic component and connecting them to the external electrode
321
formed on the sides of the laminated electronic component. However, for simplicity of explanations, the positions of the via holes in the figure are schematically shown with dotted line on the exploded perspective view in principle.
Then,
FIG. 23
shows another example of a perspective view of a conventional laminated electronic component.
In
FIG. 23
, the laminated electronic component
3901
is constructed of a laminated body
3902
formed of a plurality of laminated dielectric sheets and external electrodes
3903
. The inner layer of the laminated body
3902
contains at least one inner circuit (not shown) provided with input/output terminals and at least one inner grounding electrode (not shown).
On at least one side of the laminated body
3902
, the external electrodes
3903
are formed and these external electrodes
3903
are electrically connected to the input/output terminals of the inner circuit and the inner grounding electrode respectively. Here, suppose the one electrode connected to the input/output terminals of the inner circuit is an external electrode
3903
a
and the other electrode connected to the inner grounding electrode is an external electrode
3903
b.
The external electrodes
3903
a
and
3903
b
are formed by applying a metal film to specific locations of the sides of the laminated body
3902
and all external electrodes are formed extending from the top surface to the bottom surface occupying a wide range of area.
However, in the case of the conventional configuration shown in
FIG. 3
, an input electrode, output electrode and grounding electrode exist as external electrodes on the sides of the laminated electronic component including a plurality of circuits, and therefore there is a plurality of external electrodes formed on the sides of the laminated electronic component, which reduces the area occupied by the grounding electrode. Therefore, it is not possible to secure a sufficient area for the grounding electrode with these external electrodes alone, causing a problem that electric grounding strength is weakened. The electric grounding strength means an electric grounding state and is also simply called grounding strength. Further, The ideal electric grounding state is the state where the electric potential is zero. Accordingly, “grounding strength is weak” means the state apart from the ideal grounding state, and “grounding strength is strong” means the state close to the ideal grounding state.
Here, the grounding electrode refers to an electrode to be connected to a predetermined grounding surface on a motherboard (not shown) on which the laminated electronic component is to be mounted by means of soldering, etc.
On the other hand, in the case of the conventional laminated electronic component shown in
FIG. 23
, the external electrode
3903
a
electrically connected to the input/output terminals of the inner circuit and the external electrode
3903
b
electrically connected to the inner grounding electrode have almost the same shape and are formed extending from the top surface to the bottom surface of the laminated body
3902
occupying a wide range of area.
For this reason, especially when the area of the external electrode
3903
a
electrically connected to the input/output terminals of the inner circuit is large, parasitic components such as a conductance component or inductance component are generated especially in the external electrode
3903
a
of these external electrodes
3903
, leading to deterioration of characteristics when the device is used for a high frequency area.
Especially, when used as a laminated filter, etc. that handles an input signal of 1 GHz or greater, the above-described conventional laminated electronic component shown in FIG.
3
and
FIG. 23
has the problem that the high frequency characteristic of the filter circuit, etc., that is, the characteristic of selecting frequencies in a high frequency area deteriorates.
DISCLOSURE OF THE INVENTION
The present invention has been achieved in view of these problems of the above-described conventional laminated electronic component and it is an object of the present invention to provide a laminated electronic component capable of sufficiently securing a grounding electrode and increasing the grounding strength.
Further, in view of these problems of the above-described conventional laminated electronic component, it is another object of the present invention to provide a laminated electronic component with an excellent characteristic of selecting frequencies in a high frequency area.
One aspect of the present invention is a laminated electronic component comprising:
a dielectric layer A provided with a first shield electrode on one principal plane;
a dielectric layer C which is a dielectric layer indirectly placed above said dielectric layer A, provided with a second shield electrode on one principal plane;
a dielectric layer D whose at least one principal plane is exposed outside;
a dielectric layer B which is placed between said dielectric layer A and said dielectric layer C, and includes an inner circuit; and
a first grounding electrode provided on the other principal plane of said dielectric layer A or said one principal plane of said dielectric layer D,
wherein a via hole is provided in at least one of said dielectric layer A or said dielectric layer D,
said first shield electrode and said second shield electrode are electrically connected, and
said first grounding electrode and said first shield electrode are electrically connected through via holes provided on said dielectric layer A or said first grounding electrode and said second shield electrode are electrically connected through via holes provided on said dielectric layer D.
Another aspect of the present invention is the laminated electronic component, comprising an end face electrode provided on one side of said laminated electronic component to electrically connect said first shield electrode and said second shield electrode.
Still another aspect of the present invention is the laminated electronic component, wherein said dielectric layer B includes a resonator electrode
Ishizaki Toshio
Kagata Hiroshi
Kawakita Kouji
Matsumura Tsutomu
Nakamura Hiroyuki
Matsushita Electric - Industrial Co., Ltd.
Pascal Robert
RatnerPrestia
Takaoka Dean
LandOfFree
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