Wave transmission lines and networks – Coupling networks – Frequency domain filters utilizing only lumped parameters
Reexamination Certificate
2002-07-10
2003-12-09
Tokar, Michael (Department: 2819)
Wave transmission lines and networks
Coupling networks
Frequency domain filters utilizing only lumped parameters
C333S172000, C333S133000, C333S134000, C333S132000, C333S177000, C333S204000
Reexamination Certificate
active
06661312
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multilayer filter array, which is compact and has capability of considerable noise minimization, and is used in noise elimination for electrical equipment and the like.
2. Description of the Related Art
Demands for miniaturization and weight reduction of equipment whereto electronic components are integrated have been recently increasing; thus, demands for small-sized multilayer electronic components have been rapidly increasing. By integrating a plurality of coils and capacitors respectively, a filter array, which is an arrayed noise filter, has come into use as a type of multilayer electronic component for high-frequency noise countermeasures of circuit boards.
The internal configuration of this conventional filter array, which is an arrayed noise filter, is illustrated in FIG.
9
.
In other words, this filter array has a configuration of layered insulator layers
1
through
16
, wherein conductive patterns
101
A through
109
A and conductive patterns
111
A through
115
A, which respectively configure each signal line of this filter array, are arranged within each respective layer as illustrated in FIG.
9
.
In addition, it has a configuration wherein coils
141
through
144
and capacitors
131
through
138
are connected therebetween by input/output terminals
171
A through
174
B (shown in
FIG. 10
) of the respective lines, which are provided at both side surfaces of this filter array. Furthermore, it is also a configuration wherein ground terminals
175
,
176
(shown in
FIG. 10
) are arranged at both end surfaces of the filter array.
However, in the configuration of the conventional filter array shown in
FIG. 9
, the ground conductive pattern
101
A, which is shown typified in
FIG. 11A
, has three narrow portions
121
such as to have a form corresponding to each conductive pattern
102
A shown typified in FIG.
11
B.
Consequently, inductance has inevitably increased due to making the configuration of each ground conductive patterns
101
A,
103
A,
105
A,
107
A and
109
A respectively having a plurality of narrow portions
121
. In other words, other than coils
160
and
164
actually existing at both end lead-out portions
122
as with the equivalent circuit shown in
FIG. 10
of this conventional filter array, coils
161
,
162
,
163
actually exist so as to correspond to the inner side of these narrow portions
121
.
As a result, in consequence of the inductance due to the coil
161
, the damping characteristic of the noise filter between the input/output terminals
172
A and
172
B is degraded. Consequently, there is a drawback of vastly differing characteristics between the damping characteristic of the noise filter positioned between the input/output terminals
171
A and
171
B (indicated by the dotted line in
FIG. 12
) and the damping characteristic of this noise filter positioned between the input/output terminals
172
A and
172
B (indicated by the solid line in FIG.
12
), as shown in FIG.
12
. Furthermore, it can be similarly said that the damping characteristics of the noise filter between the input/output terminals
172
A and
172
B and the noise filter between the input/output terminals
173
A and
173
B differ; and it can be similarly said that the damping characteristics of the noise filter between the input/output terminals
173
A and
173
B and of the noise filter between the input/output terminals
174
A and
174
B differ.
On the other hand, a filter array with a distributed-constant construction, whereby signal side coils and ground side coils are opposingly arranged via the insulator layers such that the inductance of each ground side coil mutually correspond, is disclosed in the Japanese Patent Application Laid-open No. 2001-60840. However, with the structure of the filter array disclosed in this publication, since the coil inductance values and the capacitor capacitance values cannot respectively be independently changed, there is the drawback whereby control of damping characteristics is difficult.
SUMMARY OF THE INVENTION
The present invention aims to provide a multilayer filter array, which is able to independently adjust inductance and capacitance, as well as make disparity of damping characteristics between signal lines small.
According to a first aspect of the present invention, a multilayer filter array, which is formed by layering a plurality of insulator layers in a state where a plurality of conductive patterns are internally arranged, comprising coils corresponding to respective plurality of lines, which are formed by arranging the plurality of conductive patterns respectively to a single insulator layer; and capacitors corresponding to respective plurality of lines, which are formed by facing the conductive patterns to each other with insulator layers therebetween on insulator layers differing from the insulator layers the coils exist thereupon, wherein only a single conductive pattern, which configures a capacitor corresponding to a respective line, of the capacitors corresponding to respective plurality of lines, is deployed on each respective insulator layer forming each of the capacitors, is provided.
According to such multilayer filter array, operations as in the following take effect.
The multilayer filter array according to this aspect is formed by layering a plurality of insulator layers in a state where a plurality of conductive patterns are internally arranged. Then, coils corresponding to respective plurality of lines are formed by arranging the plurality of conductive patterns respectively to a single insulator layer. In addition, capacitors corresponding to respective plurality of lines are formed by facing the conductive patterns to each other with insulator layers therebetween on insulator layers differing from the insulator layers the coils exist thereupon.
Moreover, it is a configuration wherein only a single conductive pattern, which configures a capacitor corresponding to a respective line, of the capacitors corresponding to respective plurality of lines, is arranged on each respective insulator layer forming each of the capacitors. Thus, the arrangements and configurations of the conductive patterns forming the capacitors are made to differ from those of conventional techniques.
As a result, in this aspect, it has a configuration wherein not only are the coils and capacitors arranged on different insulator layers from each other, but only a single conductive pattern, which configures a capacitor corresponding to a respective line, of the capacitors corresponding to respective plurality of lines, is arranged on each respective insulator layer. Thus, for example, by merely changing the width of the conductive patterns or the number of insulator layers, not only may the inductance of coils be adjusted, but the capacitance of capacitors may be independently and easily adjusted.
Furthermore, signal conductive patterns and ground conductive patterns exist among the conductive patterns forming the capacitors of this aspect. However, by arranging on each insulator layer only a single conductive pattern, which configures a capacitor corresponding to a respective line, of the capacitors corresponding to respective plurality of lines, the narrow portion that existed in the conventional technique multilayer filter array disappears, and the inductance of the ground conductive patterns forming the capacitors becomes small.
Accordingly, since the degradation of the damping characteristics is reduced, the originally designed strong damping characteristics are obtained; moreover since no difference of inductance between each signal line made from the respective ground conductive patterns occurs, difference in damping characteristics between each signal line may be reduced.
Moreover, as the conductive patterns or internal electrodes, which determine the capacity of the capacitors corresponding to respective lines, are not adjacent to each other within the same layer, the capacitor capacity that existed between each line with the c
Mai Lam T.
TDK Corporation
Tokar Michael
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